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HDevelop User's Guide
This is your comprehensive guide to HDevelop. It describes the graphical user interface, the language used in HDevelop programs, and explains how to export programs to other programming languages like C++, C#, or Visual Basic (.NET).
HDevelop User's Guide
www.mvtec.com
MVTec Software GmbH
Machine Vision Technologies
München, Germany
MVTec Software GmbH Building Vision for Business
HDevelop, the interactive development environment of HALCON, Version 9.0.4
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher.
Edition 1
Edition 2
Edition 3
Edition 4
Edition 5
Edition 6
Edition 6a
Edition 7
Edition 7a
Edition 8
Edition 8a
Edition 8b
Edition 9
Edition 9a
Edition 9b
Edition 10
Edition 10a
Edition 10b
July 1997
November 1997
March 1998
April 1999
October 2000
June 2002
December 2002
December 2003
July 2004
July 2005
April 2006
December 2006
June 2007
October 2007
April 2008
December 2008
June 2009
March 2010
(HALCON 5.1)
(HALCON 5.2)
(HALCON 6.0)
(HALCON 6.1)
(HALCON 6.1.1)
(HALCON 7.0)
(HALCON 7.0.1)
(HALCON 7.1)
(HALCON 7.1.1)
(HALCON 7.1.2)
(HALCON 8.0)
(HALCON 8.0.1)
(HALCON 8.0.2)
(HALCON 9.0)
(HALCON 9.0.1)
(HALCON 9.0.2)
Copyright © 1997-2011 by MVTec Software GmbH, München, Germany
MVTec Software GmbH
Protected by the following patents: US 7,062,093, US 7,239,929, US 7,751,625, US 7,953,290, US
7,953,291. Further patents pending.
Microsoft, Windows, Windows NT, Windows 2000, Windows XP, Windows Server 2003, Windows
Vista, Windows Server 2008, Windows 7, Microsoft .NET, Visual C++, Visual Basic, and ActiveX are either trademarks or registered trademarks of Microsoft Corporation.
Silicon Graphics, SGI, IRIX, and OpenGL are either trademarks or registered trademarks of Silicon
Graphics, Inc.
All other nationally and internationally recognized trademarks and tradenames are hereby recognized.
More information about HALCON can be found at: http://www.halcon.com/
About This Manual
This manual is a guide to HDevelop, the interactive development environment for the HALCON machine vision library. It provides all the necessary information to understand HDevelop’s philosophy and to use
HDevelop.
This manual is intended for users who want to use HDevelop as a convenient gateway to the HALCON library or who want to deploy and test machine vision applications with it. However, it is not an introduction to the HALCON machine vision library. A working knowledge of the concepts of HALCON is assumed. Please refer to the Quick Guide to become acquainted with HALCON.
This manual does not assume that you are an expert in image processing. Regardless of your skills, it is quite easy to work with HDevelop. Nevertheless, it is helpful to have an idea about the functionality of
graphical user interfaces (GUI)
, and about some basic image processing aspects.
The manual is divided into the following chapters:
• Introducing HDevelop
This chapter explains the basic concepts of HDevelop.
• Getting Started
This chapter explains how to start HDevelop. It provides a quick overview of the graphical user interface, and shows you how to run the supplied example programs.
• Acquiring Images with HDevelop
This chapter explains the fundamental part of machine vision applications – how to acquire images.
• Programming HDevelop
This chapter explains how to develop applications in HDevelop.
• Graphical User Interface
This chapter explains the graphical user interface of HDevelop and how to interact with it.
• HDevelop Assistants
This chapter describes how to use the machine vision assistants of HDevelop.
• HDevelop Language
This chapter explains the syntax and semantics of the language used in HDevelop expressions.
• Code Export
This chapter explains the export of a HDevelop program to C, C++, Visual Basic, Visual Basic
.NET, or C#.
1 consult your operating system’s documentation for general information.
• Tips & Tricks
This chapter describes keycodes, warning and error windows, and provides miscellaneous information.
Contents
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3 Acquiring Images with HDevelop
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Acquiring Images From Files or Directories
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Acquiring Images Through Image Acquisition Interfaces
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Understanding the Image Display
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Improving the Threshold Using the Gray Histogram
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4.12 Selecting Regions Based on Features
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Program Counter, Insert Cursor, and Break Points
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Creating and Editing Procedures
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5.10.1 Interactive Visual Operations
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5.12 Feature Inspection Window
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Introducing the Calibration Assistant of HDevelop
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How to Calibrate with the Calibration Assistant
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Calibration Assistant Reference
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Introducing the Matching Assistant of HDevelop
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How to Use the Matching Assistant of HDevelop
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Expressions for Input Control Parameters
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General Features of Tuple Operations
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7.5.10 Trigonometric Functions
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7.5.13 Miscellaneous Functions
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Tracking the Return Value of Operator Calls
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Summary of HDevelop operations
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Limitations and Troubleshooting
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Code Generation for C# (HALCON/.NET)
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Limitations and Troubleshooting
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Code Generation for C# (HALCON/COM)
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Limitations and Troubleshooting
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Code Generation for Visual Basic .NET (HALCON/.NET)
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Limitations and Troubleshooting
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Code Generation for Visual Basic .NET (HALCON/COM)
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Limitations and Troubleshooting
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Code Generation for Visual Basic 6 (HALCON/COM)
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Limitations and Troubleshooting
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General Aspects of Code Generation
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Introducing HDevelop 9
Chapter 1
Introducing HDevelop
HDevelop is a tool box for building machine vision applications. It facilitates rapid prototyping by offering a highly interactive programming environment for developing and testing machine vision applications. Based on the HALCON library, it is a sophisticated machine vision package suitable for product development, research, and education.
There are four basic ways to develop image analysis applications using HDevelop:
• Rapid prototyping in the interactive environment HDevelop.
You can use HDevelop to find the optimal operators or parameters to solve your image analysis task, and then build the application using various programming languages, e.g., C, C++, C#, Visual
Basic .NET, or Delphi.
• Development of an application that runs within HDevelop.
Using HDevelop, you can also develop a complete image analysis application and run it within the
HDevelop environment. The example programs supplied with HDevelop can be used as building blocks for your own applications.
• Execution of HDevelop programs or procedures using HDevEngine.
You can directly execute HDevelop programs or procedures from an application written in C++ or any language that can integrate .NET or COM objects using HDevEngine. This is described in detail in the Programmer’s Guide, part VI on page 169 .
• Export of an application as C, C++, Visual Basic, Visual Basic .NET, or C# source code.
Finally, you can export an application developed in HDevelop as C, C++ , Visual Basic, Visual
Basic .NET, or C# source code. This program can then be compiled and linked with the HALCON library so that it runs as a stand-alone (console) application. Of course, you can also extend the generated code or integrate it into existing software.
Let’s start with some facts describing the main characteristics of HDevelop.
10 Introducing HDevelop
1.1
Facts about HDevelop
HDevelop actively supports your application development in many ways:
2 With the graphical user interface of HDevelop, operators and iconic objects can be directly selected, analyzed, and changed within a single environment.
2 HDevelop suggests operators for specific tasks. In addition, a thematically structured operator list helps you to find an appropriate operator quickly.
2 An integrated online help contains information about each HALCON operator, such as a detailed description of the functionality, typical successor and predecessor operators, complexity of the operator, error handling, and examples of application. In addition, the online help provides a search facility that allows to search the complete documentation of HALCON.
2 HDevelop comprises a program interpreter with edit and debug functions. It supports standard programming features, such as procedures, loops, or conditional statements. Parameters can be changed even while the program is running.
2 HDevelop immediately displays the results of operations. You can try different operators and/or parameters, and immediately see the effect on the screen. Moreover, you can preview the results of an operator without changing the program.
2 Several graphical tools allow to examine iconic and control data online. For example, you can extract shape and gray value features by simply clicking onto the objects in the graphics window, or inspect the histogram of an image interactively and apply real-time segmentation to select parameters.
2 Built-in graphical assistants provide interactive interfaces to more complex machine vision tasks.
The assistants can also generate HDevelop code in the current program.
2 Variables with an automatic garbage collection are used to manage iconic objects or control values.
1.2
HDevelop Procedures
HDevelop offers a mechanism for the creation and execution of procedures. Procedures are meant to increase the readability and modularity of HDevelop programs by encapsulating functionality of multiple operator calls in one or more procedure calls. It also makes it easier to reuse program code in other
HDevelop programs by storing repeatedly used functionality in external procedures.
An HDevelop procedure consists of an interface and a program body. Procedure interfaces resemble the interfaces of HALCON operators, i.e., they contain parameter lists for iconic and control input and output parameters. The procedure body contains a list of operator and procedure calls. Furthermore,
HDevelop provides extensive support to supplement procedures with structured documentation. The documentation is automatically integrated into the online help system.
Every HDevelop program is made up of one or more procedures. It always contains the main procedure, which has a special status inside the program, because it is always the top-most procedure in the calling hierarchy and cannot be deleted from the program.
1.3 HDevelop XL
HDevelop offers all necessary mechanisms for creating, loading, deleting, copying, modifying, saving, and exporting procedures. Once a procedure is created, it can basically be used like an operator: Calls to the procedure can be added to any program body and be executed with the appropriate calling parameters.
Generally, the concept of using procedures inside HDevelop is an extension to the concept of calling
HALCON operators since procedure and operator interfaces have the same parameter categories, and the same rules apply for passing calling parameters.
Local and external procedures are differentiated in HDevelop. Local procedures are stored inside the
HDevelop program while external procedures are stored separately and therefore can be shared between different HDevelop programs and, what is most advantageous, the modification of an external procedure immediately affects all HDevelop programs using it. In order to manage a large collection of procedures, the procedures can be ordered in a hierarchical way, i.e., procedures can be ordered by chapters and sections just like operators. Furthermore, external procedures can be protected by passwords, so that they can be applied but not viewed or modified by unauthorized users.
1.3
HDevelop XL
In addition to the standard HDevelop, there is also a variant called HDevelop XL, which is based on
HALCON XL. The user interface is identical, but underneath HALCON XL is optimized for large images. In the remainder of this document, when we refer to HDevelop you can substitute HDevelop XL if that is the variant you will be using.
1.4
Terminology & Usage
HDevelop adheres to well-established conventions and usage patterns regarding its graphical user interface. Most of the terminology explained here will have become second nature to most users and may most likely be skimmed over.
Mouse Usage
click A single click with the left mouse button, e.g., to mark and select items or to activate buttons. To select multiple items, hold down the <Ctrl> key and click the desired items. To select many items from a list, click the first item, hold down the <Shift> key and click the last item. All intermediate items are then also selected.
double-click Two quick successive clicks with the left mouse button, e.g., to open dialogs of selected items. Double-clicks are mostly shortcuts for single clicks followed by an additional action.
right-click A single click with the right mouse button to access additional functionality of the user interface, e.g., context-sensitive menus. Clicking the right mouse button also ends interactive drawing functions in HDevelop.
drag Keeping the left mouse button pressed while moving the mouse and finally releasing the mouse button. Typically used to move items, resize windows, select multiple items at once, e.g., program lines, or to draw shapes.
11
12 Introducing HDevelop
drag-and-drop HDevelop supports drag-and-drop of image files and HDevelop programs from other applications. You can, e.g., drag an HDevelop program icon from a file browser and drop it on the
HDevelop window to load it.
middle mouse button With three-button mice, the middle mouse button is used under UNIX to paste text from the clipboard into text fields.
mouse wheel Most recent three-button mice combine the middle mouse button with a scrolling wheel.
HDevelop supports the mouse wheel in many places. The mouse wheel operates the GUI element under the mouse cursor. Using the mouse wheel you can, for instance, quickly scroll large program listings, select values from lists or perform continuous zooming of displayed images. In general, windows that provide a scroll bar can be quickly scrolled with the mouse wheel. Furthermore, the values of spinner boxes (text fields that expect numerical data) can be decremented and incremented with the mouse wheel.
Keyboard Usage
HDevelop is very keyboard-friendly. Most functions of the graphical user interface that can be operated using the mouse can be accessed from the keyboard as well. Many of the most important functions are available through keyboard shortcuts, which are worthwhile memorizing. When programming with
HDevelop, keeping both hands on the keyboard can increase the productivity. Therefore, many navigational tasks like selecting parameter fields or selecting values from lists can be easily done using just the keyboard. The most common keyboard functions are listed in the appendix.
Windows and Window Managers
In the default window mode of HDevelop, windows can be freely moved inside the main window by dragging the title bar. They can be resized by dragging the window border. Windows can be focused by clicking inside the window area. This also raises the corresponding window to the front. Windows that are completely covered by other windows can be brought to the front by selecting them from the Window menu.
The window title provides some buttons with additional functionality. Clicking the icon in the left edge of the window title opens a menu from which all window management functions (move, resize, minimize...) can be selected. The buttons on the right edge of the window allow to 1) minimize/restore, 2) maximize/restore, and 3) close the corresponding window (from left to right).
maximize menu minimize close
Figure 1.1: Window title.
There is an alternative window mode called SDI (see also
on page
functionality of the window title to the window manager.
Abbreviations
BP break point
IC insert cursor
GUI graphical user interface
MDI multi-document interface
PC program counter
SDI single-document interface
XLD extended line description (see also
on page
1.4 Terminology & Usage 13
14 Introducing HDevelop
Getting Started 15
Chapter 2
Getting Started
In this chapter the following topics are covered:
• running HDevelop
• specifying command line switches
• short introduction to the windows of HDevelop
• running example programs in HDevelop
2.1
Running HDevelop
In the following it is assumed that HALCON has already been installed as described in the Installation
Guide.
Windows
Under Windows, HDevelop is usually started from the Windows “Start” menu:
Start . Programs . MVTec HALCON . HDevelop
You can also start HDevelop from the Windows Command Prompt or from the Start . Run... menu, making it easy to pass optional command line switches: hdevelop
UNIX
Under UNIX, HDevelop is started from the shell: hdevelop &
16 Getting Started
window title
1
graphics window menu bar tool bar
2
operator window
4
variable window
3
program window status bar
Figure 2.1: User interface.
Command Line Switches
Under both Windows and UNIX, HDevelop supports several command line switches to modify its startup behavior. You can add the name of an HDevelop program on the command line to load it directly. This is identical to an invocation of HDevelop without any parameters and a subsequent loading of the program.
Or, you can convert HDevelop programs to other programming languages without opening the graphical user interface at all. A full list of the supported command line switches is available with the following command: hdevelop --help
See
on page
for a listing of the available switches.
2.1 Running HDevelop
User Interface
When HDevelop is started for the first time it looks similar to
. The main window offers a menu
and a tool bar for quick access to frequently used functions. The status bar at the bottom of the window displays messages and image properties. In addition, the following windows are available by default:
1. Graphics window
This window displays iconic data: images, regions, and XLDs. It provides its own tool bar to quickly zoom and pan the displayed image, and a context menu to adapt the visualization settings.
The context menu is available by right-clicking inside the window
It contains the most frequently used entries from the menu Visualization. You can open multiple graphics windows. The one marked with a lit bulb in the upper right corner is the active graphics window, i.e., it is the target for subsequent display operations. The graphics window works like an image stack: Images can be overlayed with regions or XLDs, or with images that have a reduced domain.
2. Operator window
You can select HALCON operators (and HDevelop procedures) in this window. The parameters of the selected operator can be specified, and the operator can be executed, entered in the current program, or both. You can also get online help for the selected operator from this window.
3. Program window
This window displays the current program. It provides syntax highlighting with user-definable colors. The left column displays the program line numbers. The small black triangle is the insert cursor, which is where new program lines will be added. In the following, it is referred to as
IC. The green arrow is the program counter which marks the next line to be executed. In the following, the program counter is referred to as PC. You can also add or remove break points in the current program in this column. These will halt the program execution at user-defined places so that intermediate results may be examined.
The program source can be edited directly in this window provided that the full text editor is enabled (see
on page
105 ). When adding new lines or modifying existing lines, advanced
autocompletion features speed up typing and help keeping the program consistent. Program lines can also be modified by double-clicking them and editing them in the operator window. This is the classical way to edit HDevelop programs. It is a more form-based approach to program editing.
Furthermore, different parameters can be easily tested in the operator window without changing the program. Both the full text editor and the operator window can be used interchangeably for program editing.
4. Variable window
Program variables can be watched in this window. It displays all variables of the current procedure and their current values. Iconic variables are displayed as thumbnails, whereas control variables are displayed as text. The layout of this window can be switched between horizontal and vertical splitting by double-clicking the separator. You can double-click iconic variables to display them in the active graphics window. Double-clicking control variables opens an inspection window with a nicely formatted list of the current values and statistical data.
There are many other windows which will be covered later in this manual.
1
Unless the context menu has been disabled in the preferences to prevent any interference with interactive drawing functions.
See
on page
17
18 Getting Started
2.2
Running Example Programs
HALCON comes with a large number of HDevelop example programs from a variety of application areas. These range from simple programs that demonstrate a single aspect of HALCON or HDevelop to complete machine vision solutions. As an introduction to HDevelop we recommend to try some of these programs to quickly get accustomed to the way HDevelop works.
One of the examples demonstrates many different capabilities of HALCON in one program. It is the only
HDevelop example program that can be started from the “Start” menu under Windows. The UNIX path to this program is $HALCONROOT/examples/hdevelop/explore_halcon.dev. Running this program is highly recommended to get a good overview of the many application areas of HALCON.
Figure 2.2: Explore the power of HALCON.
The example programs have been categorized by application area, industry, method, and operator usage.
A special category “New in version” groups examples by their appearance in specific HALCON releases.
Browsing these categories, you can quickly find example programs that cover image processing problems that you may wish to solve with HALCON. These programs may serve as a foundation for your own development projects.
2.2 Running Example Programs 19
Figure 2.3: Browse Examples dialog.
Browse and Load Example Programs
• Click File . Browse Examples....
This will open the example program browser (see
). Similar to a file browser, it shows
a tree of categories on the left and a list of example programs from the selected categories on the right. Categories that contain hidden subtopics are marked with a + . Double-click on a category label to open the subtopics (or click + ). Double-click again to close the subtopics (or click − ).
Browse the categories: Click on a category to select it and display its example programs. You can select multiple categories at once by holding the <Ctrl> key while clicking on the categories.
Filter the example programs: To reduce the amount of listed example programs, enter a word or substring into the Filter text field. Subsequently, only example programs matching this substring in the file name or short description will be displayed.
We pretend that you are looking for a measuring example from the semiconductor industry:
• Click on + next to Industry.
• Click on the subtopic Semiconductors. The examples belonging to the semiconductor industry are listed on the right.
• Enter the word measure into the Filter text field.
Note how the list is updated as you type. Now, you have a short list of example programs to select from. You may need to resize the example browser to fully read the short descriptions of the listed programs.
• Select measure_ic_leads.dev by clicking on it.
• Click Open. The selected example program is then loaded. Alternatively, you can load an example program by double-clicking on it. The example browser is closed unless Keep dialog open is checked.
The program lines of the loaded example program are now displayed in the program window. The PC is set to the first executable line of the program (leading comments are ignored). The variable window is also updated: It lists the variables that are used in the main procedure, which is initially the current procedure. The variables are currently uninstantiated, i.e., their current value is undefined. This is indicated by the question mark (?). Both windows are displayed in
20 Getting Started
iconic variables control variables PC (program counter) current procedure
Figure 2.4: The variable and program window after loading the example program.
Run Example Program
• Click Execute . Run or click the corresponding button from the tool bar (see
The program line next to the PC is executed, the PC is moved to the following line and so forth until the execution stops. There are four reasons for the program execution to stop: 1) the last program line has been executed, 2) a breakpoint has been reached, 3) the HDevelop instruction stop has been encountered as in this example, or 4) an error has occurred.
During execution, the graphics window is used for visualization. Changes to the variables are reflected in the variable window. When the program execution stops, the status bar displays the number of executed lines and the processing time.
To continue with the program execution, click Execute . Run again until the end of the program is reached.
• Click Reset Program Execution to reset the program to its initial state. (see
• Using the button Step Over you can execute the program line by line and inspect the immediate effect of each instruction.
Run Step Over Stop Reset Program Execution
Figure 2.5: The basic execution buttons.
Acquiring Images with HDevelop 21
Chapter 3
Acquiring Images with HDevelop
Image acquisition is crucial for machine vision applications. It will usually be an early if not the first step in your programming projects. This chapter explores the different ways of image acquisition in
HDevelop.
3.1
Reading Images From Files
Especially in the prototyping phase you often have a set of sample image files to work from. HDevelop
(or rather the underlying HALCON library) supports a wealth of image formats that can be loaded directly (see read_image in the Reference Manual).
Drag-and-Drop
The easiest way to read an image is to simply drag it from a file browser to the HDevelop window and drop it there. When the file is dropped, HDevelop opens the dialog Read Image (see
This dialog displays the full path of the image and automatically proposes a variable name derived from the file name. This name can be edited, or another iconic variable name from the current program may be selected from the drop-down list.
Furthermore, a preview of the image and basic image properties are displayed in the dialog (width, height, color type, and number of channels). If you picked the wrong image, you can select another one from the same directory by pressing the button next to the file name. This will open a file browser native to the operating system, i.e., on Windows you may be able to switch to thumbnail view in this dialog.
When another image is selected, the dialog is updated accordingly.
When you click the button OK, the instruction read_image is added to the current program. With the setting of Insert Position you determine where the instruction will be put: At the IC or the PC. If you changed your mind about reading the selected image at all, click Cancel.
22 Acquiring Images with HDevelop
Figure 3.1: After dragging an image file onto the HDevelop window.
Images from Selected Directories
Apart from dragging and dropping images, there is an equivalent method from within HDevelop: Select
File . Read Image to get a list of image directories to choose images from. Again, this will open a native file selection dialog. Browse to and select the desired image from there, and click OK to open up the dialog Read Image described above.
3.2
Viewing Images
When images are read as described above, they are automatically displayed in the active graphics window. This is the default behavior in HDevelop, but the automatic display of images can be suppressed if desired, e.g., to speed up computationally intensive programs.
Initially, the loaded image fills the graphics window entirely. The window itself is not resized so the aspect ratio of the image might be skewed. Using the tool box of the graphics window you can easily zoom the image, or change the window size with regard to the image.
We recommend to adapt the window size to the size of the image because otherwise the display is slowed down. The image size, the window size and the displayed part of the image are set with the tool bar icons of the graphics window (see
An iconic view of the loaded image is also displayed in the variable window. When the image is cleared in the graphics window, it can always be restored by double-clicking this icon.
3.3 Image Acquisition Assistant 23
clear select magnify image size pan image zoom in/out window size
Figure 3.2: Tools in the graphics window.
3.3
Image Acquisition Assistant
The image acquisition assistant is a powerful tool to acquire images from files (including AVI files), directories or image acquisition devices supported by HALCON through image acquisition interfaces.
To use this assistant, select Assistants . Open New Image Acquisition. The window is displayed in
. It features several tab cards that can be stepped through one after another. Ultimately, the
assistant generates HDevelop code that can be inserted into the current program. Select the entry Help in the menu of the image acquisition assistant to open its online help.
Figure 3.3: Image acquisition assistant.
The tab card Source determines the acquisition method and the image source. In the default setting images are acquired from files. This is described in the following section. Alternatively, images are acquired from an image acquisition device, e.g., a camera. This is described in
on page
3.3.1
Acquiring Images From Files or Directories
You can specify a selection of image files or a directory to load images from. Make sure the radio button
Image File(s) is selected in the tab card Source. You can directly enter image names or the name of a directory into the text field. Multiple image names are separated by a semicolon. Usually, it is more convenient to use one of the following buttons:
24 Acquiring Images with HDevelop
Select File(s) ...
HDevelop opens a file selection dialog in the current working directory, displaying the image files supported by HALCON. Multiple image files can be selected by holding down the <Ctrl> key while clicking additional image files. Click Open to confirm the selection. The first selected image is displayed in the active graphics window.
Select Directory ...
HDevelop opens a directory browser. It is not possible to select multiple directories. Confirm your selection by clicking Open or OK. The first image from the selected directory is displayed in the active graphics window. If the check box Recursive is ticked, all subdirectories of the specified directory are scanned for images as well.
View Images
You can single-step through the selected images by clicking the Snap button (see
you click the button, the next image is displayed in the active graphics window. You can also loop through the images by clicking the button Live. This is especially useful for animations. Both functions are also available from the menu Acquisition.
Snap (single−step images)
Connect Live (continuous display)
Figure 3.4: Browsing the selected images.
Generate Code
Switch to the tab card Code Generation, and specify a variable name in the text field Image Object.
You can later access the image in the program by this name. If multiple images or a directory were selected in the tab card Source, the image acquisition assistant will read the images in a loop. In this case the following additional variable names need to be specified:
Loop Counter: The name of the loop index variable. While looping over the images in the program, this variable will contain the object number of the current image.
Image Files: The name of the variable that will contain the names of the selected images.
Click Code Preview to inspect the code that would be generated from the currently specified parameters.
Click Insert Code to generate the code and insert it at the position of the IC in the current program.
The following piece of code is an example generated from three selected images. It is a self-contained
HDevelop program that runs without alteration.
3.3.2 Acquiring Images Through Image Acquisition Interfaces 25
Figure 3.5: Specifying variable names and previewing the code.
* Code generated by Image Acquisition 01
ImageFiles := []
ImageFiles[0] :=
'C:/Program Files/MVTec/HALCON/images/fin1.png'
ImageFiles[1] :=
'C:/Program Files/MVTec/HALCON/images/fin2.png'
ImageFiles[2] :=
'C:/Program Files/MVTec/HALCON/images/fin3.png' for Index := 0 to |ImageFiles| - 1 by 1 read_image (Image, ImageFiles[Index])
* endfor
Do something
3.3.2
Acquiring Images Through Image Acquisition Interfaces
Select Image Acquisition Interface in the Source tab. The drop-down list below the radio button becomes active. Initially, it lists all image acquisition interfaces supported by HALCON. You can tidy this list by clicking the button Detect. HDevelop will then probe all the image acquisition interfaces and remove those that do not respond. Probing the interfaces might cause the system to hang due to erroneously installed drivers or hardware failures. If there are unsaved changes in the current program,
HDevelop will display a warning dialog. You are advised to save the changes before you proceed. You can also ignore the warning and proceed, or abort the operation. After the interfaces have been probed, you can select the desired image acquisition interface from the list.
Selecting the entry Help from the menu of the image acquisition assistant will open the online help for the selected image acquisition interface.
26 Acquiring Images with HDevelop
detect image acquisition interfaces...
... and select from the list
Figure 3.6: Source selection (example).
Connect to the Device
Once an image acquisition interface is selected, its connection parameters are detected and updated in the tab card Connection (see
). Here you can specify the device that is connected to the selected
image acquisition interface. If, for example, the interface of a frame grabber board with multiple cameras has been selected as the source, the actual device can be selected here. The parameters of this tab card are described in general in the reference section of the operator open_framegrabber
; please refer to the HTML page of the selected interface for detailed information (menu Help).
Figure 3.7: Connection parameters (example).
If the acquisition interface File is selected, two buttons become available to select an image file or an image directory, respectively. The File interface also supports AVI files, or sequence files (.seq). The latter are special to HALCON; they contain a list of image file names that will be loaded in succession.
Specify the desired connection parameters and click Connect to establish or update the connection to the actual device. The connection status can also be toggled in the tool bar (see
on page
3.3.2 Acquiring Images Through Image Acquisition Interfaces
You can grab single images with the button Snap, or switch to continuous grabbing mode using the button Live. Live mode can be stopped by clicking the same button again which is now labeled Stop.
Clicking the button Detect attempts to re-detect valid parameters for the currently selected image acquisition interface. Usually, this is done automatically, when the interface is selected from the list on the tab card Source.
The button Reset All sets all connection parameters back to their default values.
Set Device Parameters
The tab card Parameters contains a list of parameters specific to the selected device. It becomes available once the connection to the device has been activated. See
for an example parameter list. Please refer to the HTML page of the selected interface for detailed information. You can click the help button of the assistant to get to the corresponding page automatically.
Depending on the parameter type, different selection methods are enabled. As an example, parameters with a defined range of values can be specified by dragging a slider or entering the value parametrically.
If a value is changed, a reset button to the right is activated. Some parameters provide a check box which attempts to set the parameter automatically if clicked.
If Update Image is checked, parameter changes are immediately reflected in the graphics window by acquiring a new image. The button Refresh updates the list of parameters, which is useful if parameters have side effects. You can reset all parameters to their default values at once by clicking Reset All.
27
acquire new image at parameter change selection of parameters (optional) and sorting reset parameter set parameter automatically
Figure 3.8: Device-specific parameters (example).
28 Acquiring Images with HDevelop
Generate Code
On the tab card Code Generation the settings made in the other tab cards are turned into executable code. The basic structure of the code and the corresponding variable names can be specified.
Control Flow
Initialization Only: Generate only code to initialize the image acquisition interface with the parameters specified in the other tab cards and to close it down properly. Additional code for image acquisition and processing can be added later.
Acquire Single Image: Also generate code to acquire an image.
Acquire Images in Loop: Also add a loop around the image acquisition code. Further image processing can be added inside this loop.
The image acquisition interface is addressed by a so-called handle. The variable name of this handle can be specified in the text field Connection Handle. The variable name of the acquired image(s) can be set in Image Object.
Click Code Preview to inspect the code. Click Insert Code to generate the code in the program window at the IC.
Figure 3.9: Code generation.
3.3.3 Modifying the Generated Code
Here is a code example:
* Code generated by Image Acquisition 01 open_framegrabber (
'uEye', 1, 1, 0, 0, 0, 0, 'interlaced', 8, 'default', -1,
'false', 'UI154x-M', '1', 0, -1, AcqHandle) set_framegrabber_param (AcqHandle,
'exposure', 99.9248) grab_image_start (AcqHandle, -1) while (true) grab_image_async (Image, AcqHandle, -1)
* Do something endwhile close_framegrabber (AcqHandle)
3.3.3
Modifying the Generated Code
After the generated code has been inserted into the program window, HDevelop internally keeps the code linked to the corresponding assistant. This link is kept until the assistant is quit using the menu entry
File . Exit Assistant. If you close the assistant using the menu entry File . Close Dialog or using the close icon of the window, the assistant can be restored from the top of the menu Assistants.
You can change the settings inside the assistant and update the generated code accordingly. The code preview will show you exactly how the generated code lines will be updated. Furthermore, you can delete the generated code lines, or release them. When code lines are released, the internal links between the assistant and those lines is cut off. Afterwards, the same assistant can generate additional code at a different place in the current program.
29
30 Acquiring Images with HDevelop
Programming HDevelop 31
Chapter 4
Programming HDevelop
This chapter explains how to use HDevelop to develop your own machine vision applications. It is meant to be actively followed in a running instance of HDevelop. In the following, it is assumed that the preferences of HDevelop are set to the default values. This is always the case after a fresh installation of HALCON. If you are uncertain about the current settings, you can always start HDevelop with the default settings by invoking it from the command line in the following way (see also
on page
hdevelop -reset_preferences
This chapter deals with a simple example. Given is the image displayed in
count the clips and determine their orientation.
Figure 4.1: Paper clips.
4.1
Start a New Program
Start HDevelop or, if it is still running, click File . New Program to start a new program. HDevelop will notify you if there are unsaved changes in the current program. If it does, click Discard to throw away the changes and start anew. In case you rearranged the windows, click Window . Organize Windows to restore the default layout displayed in
on page
32 Programming HDevelop
The first thing to do is read the image and store it in an iconic variable. From the last chapter we know that we can simply drag an image to the HDevelop window. We also know that this inserts the operator read_image into the program. Therefore, we can just as well insert the operator directly.
4.2
Enter an Operator
Click into the text box of the operator window, type read_image and press <Return>. You can also type any partial operator name and press <Return>. HDevelop will then open a list of operators matching that partial name. This way, you can easily select operators without having to type or even know the exact name. Selection is done with the mouse or using the arrow keys to highlight the desired operator and pressing <Return>. If you selected the wrong operator by accident, you can reopen the list by clicking on the drop-down arrow next to the operator name. When entering a partial name, operators commencing with that name appear at the top of the list.
Figure 4.2: Matching operators after typing read_ and pressing <Return>.
4.3
Specify Parameters
After selecting an operator, its parameters are displayed in the operator window. They are grouped by iconic and control parameters. The icons next to the parameter names denote the parameter type: Input vs. output (see
). The semantic type is displayed to the right of the parameters. Parameters are
specified in the text fields. The first parameter gets the input focus.
Enter Clip into the text field Image. The image will be stored in this variable. Next, enter ’clip’ into the text field FileName. You can press <Tab> to go to the next input field. Pressing <Shift> <Tab> takes you back to the previous field. This way you can enter all parameters without using the mouse.
Click OK or press <Return> to submit the operator to the current program. This will do the following:
iconic output control input
4.4 Getting Help 33
semantic type data type file selection dialog
Figure 4.3: Specifying parameters.
• An operator call is added as the first line of the current program.
• The IC is advanced, so that additional lines will be added after the inserted line.
• The program line is executed and the PC is advanced. To be more precise: All the lines from the
PC to the IC are executed which makes a difference when adding program lines in larger programs.
• The character * is added to the window title to indicate unsaved changes in the current program.
• The image is displayed in the graphics window.
• The status bar is updated, i.e., the execution time of the operator read_image is displayed and the format of the loaded image is reported.
• The output variable Clip is created and displayed in the variable window.
• The operator window is cleared and ready for the insertion of the next operator.
4.4
Getting Help
You may be wondering where the clip image was loaded from since we did not specify any path or even a file extension. This is a detail that is related to the way the HALCON operator read_image works.
HDevelop does not know anything about it. It just executes the operator with the parameters you supply.
Nonetheless, it is easy to access the documentation of the operators from within HDevelop.
Double-click the first program line in the program window. The operator is displayed in the operator window for editing. Now click Help to open the HDevelop online help window. It will automatically jump to the documentation of the displayed operator (see
). The reference manual is completely
cross-linked. The navigation at the left part of the window provides quick access to the documentation.
The tab card Contents presents the hierarchical structure of the reference manual (plus access to other
HALCON manuals). The tab card Operators lists all operators for direct access. Enter any desired substring into Filter to quickly find an operator.
In the remainder of this chapter, try to use the online help as much as possible to get information about the used operators. The online help window is described in
on page
34 Programming HDevelop
Figure 4.4: The online help window showing the documentation of the operator read_image
.
4.5
Add Additional Program Lines
Select the clips by thresholding
Now, we want to separate the clips from the background, i.e., select them. They clearly stand out from the background, thus a selection based on the gray value is appropriate. This operation is known as thresholding.
Enter threshold into the operator window. This is both the full name of an operator and part of other operator names. Thus, you get a list of matching operators with threshold pre-selected when you press
<Return>. Press <Return> once more to confirm the selected operator and show its parameters.
In
you can see that the input parameter
Image is set to Clip automatically. For input variables with no default value, reasonable suggestions are inferred automatically by collecting previous output variables of the same type. Therefore, the name of the most recent matching output parameter will be suggested (most recent being the closest predecessor of the current program line). In this example, only
Clip is available.
Set
MinGray and
MaxGray to 0 and 30, respectively. This will select the dark pixels in the image.
Click Apply. This button executes the operator without adding it to the program. Additionally, it keeps the current parameters open for editing. This way, you can easily try different settings and immediately see the result. The selected pixels (the so-called region) are stored in the output variable Region, which
4.5 Add Additional Program Lines 35
Figure 4.5: Parameter suggestions.
is displayed in the variable window. The region is an image mask: White pixels are selected while black pixels are not.
The region is also displayed as an overlay in the graphics window. The selected pixels are displayed in red (unless you changed the default settings).
The selected threshold values are not perfect, but we will correct this later. For now, click Enter to add the operator to the program window. Contrary to clicking OK, this does not execute the operator. Note that the variable Region keeps its value but is no longer displayed in the graphics window. Also, the PC is not advanced, indicating that the second line of the program is yet to be executed.
Adding program lines with Enter is especially useful if some of the input parameters use variable names that will be added to the program at a later time.
Successor
Click on the just inserted program line to select it. You can let HDevelop suggest operators based on the selected line. Open the menu Suggestions . Successors. This menu is filled dynamically to show typical successors of the currently selected operator. We want to split the selected pixels into contiguous regions. Move the mouse pointer over the menu entries. The status bar displays a short description of the highlighted operator. Looking through the menu entries, the operator connection looks promising, so we click on it. Any operator selected through this menu is transferred to the operator window.
Again, the variable names suggested by HDevelop look reasonable, so press <Return>. This is equivalent to clicking the OK button (though this can be changed in the preferences of HDevelop). This time, two program lines are executed: The threshold operation and the connection operation. As noted above: Clicking OK executes from the PC to the IC.
In the graphics window, the contiguous regions calculated by the operator connection are now displayed in alternating colors.
36 Programming HDevelop
4.6
Understanding the Image Display
After having executed the three lines of our program, the graphics window actually displays three layers of iconic variables: the image Clip, the region Region, and the tuple of regions ConnectedRegions
(from bottom to top). Place the mouse pointer over the icons in the variable window to obtain basic information about the variables.
The display properties of images and the topmost region can be adjusted from the context menu of the graphics window. For images, the look-up table (henceforth called LUT) and the display mode (referred to as “paint”) can be set. The LUT specifies gray value mappings. Experiment with different settings:
Right-click in the graphics window and select some values from the menus Lut and Paint. Make sure, the menu entry Update Window is checked. Notice how the display of the image changes while the regions remain unchanged.
The menu entries Colored, Color, Draw, Line Width, and Shape change the display properties of the topmost region. Set Draw to ‘margin’, Color to ‘cyan’, and Shape to ‘ellipse’. The display of
ConnectedRegions (which is the topmost layer) changes accordingly. The region Region is still displayed in filled red.
A more convenient way to set many display properties at once is available through the menu entry Set
Parameters.... It opens the settings window displayed in
After trying some settings, click the button Reset to restore the default visualization settings.
Figure 4.6: Changing the display parameters.
You cannot change the display properties of regions (or XLDs) other than the topmost. What you can do is rebuild the image stack in the graphics window manually by double-clicking iconic variables in the variable window and changing the properties each time another layer is added. The stack is cleared
4.7 Inspecting Variables 37
Figure 4.7: Interactive inspection of an iconic variable containing regions.
whenever an image is added that uses the full domain. To clear the stack (and thus the graphics window) manually, click the clear icon (see
on page
4.7
Inspecting Variables
When you move the mouse cursor over the variable ConnectedRegions you see that it contains 98 regions.
Right-click on the icon ConnectedRegions and select Clear / Display to display only the connected regions in the graphics window. Right-click again and select Display Content . Select....
This menu entry opens a variable inspection window which lists the contents of the variable
ConnectedRegions. The selected region of this inspection window is displayed in the graphics window using the current visualization settings. Set Draw to ‘margin’ and Shape to ‘ellipse’ and select some regions from the list. An example is illustrated in
For now, close the variable inspection window. The large number of regions is due to the coarse setting of the bounds of the threshold operator. In the following we will use one of HDevelop’s visual tools to find more appropriate settings interactively.
4.8
Improving the Threshold Using the Gray Histogram
Click Visualization . Gray Histogram to open a tool for the inspection of gray value histograms.
One of its uses is to determine threshold bounds visually. Because the graphics window currently displays only regions, the gray histogram is initially empty. Double-click the Clip icon in the variable window to re-display the original image and watch its gray histogram appear.
38 Programming HDevelop
visualize threshold operation
Figure 4.8: Determining threshold bounds interactively using the gray histogram.
Select Threshold in the column Operation of the gray histogram window, and click the icon next to Threshold to visualize the operation. Now, you can try different threshold bounds by altering the values in Min and Max or by dragging the lines in the histogram area (see
these values are immediately visualized in the active graphics window. The values 0 and 56 seem suitable for the lower and upper bounds, respectively.
4.9
Edit Lines
As previously noted, the default editing mode in HDevelop is dialog-based. All parameter modifications in the program are done through the operator window. To edit a line, double-click it in the program window. Then, the parameters are displayed in the operator window for editing. If you click OK or
Enter, the original line in the program is updated. There is also a full text editor which is explained in
on page
Double-click the second line of the program to adjust the threshold operation. Replace the value 30 with
56 and click Enter. The program line is updated in the program window.
4.10
Re-Execute the Program
The last editing step was just a tiny modification of the program. Often, after editing many lines in your program with perhaps many changes to the variables you want to reset your program to its initial state and run it again to see the changes.
4.11 Save the Program
Click Execute . Reset Program Execution to reset the program. Now, you can select Execute .
Run to run the complete program, or click Execute . Step Over repeatedly to execute the program line by line.
4.11
Save the Program
Perhaps now is a good time to save your program. Select File . Save and specify a target directory and a file name for your program.
4.12
Selecting Regions Based on Features
Inspecting the variable ConnectedRegions after the changed threshold operation yields a much better result. Still, a contiguous area at the left edge of the image is returned. To obtain only the regions that coincide with the clips, we need to further reduce the found regions based on a common criterion.
Analogous to the gray histogram tool, which helps to select regions based on common gray values,
HDevelop provides a feature histogram tool, which helps to select regions based on common properties or features.
Click Visualization . Feature Histogram to open the tool. The column Feature allows to select the feature that the region selection will be based on. The default feature is “area”, which is adequate in
39
get rid of this region visualize feature selection
Figure 4.9: Selecting regions with a similar area in the feature histogram.
40 Programming HDevelop
this case: The actual clips are all the same size, thus the area of the regions is a common feature. In the feature histogram the horizontal axis corresponds to the values of the selected feature. The vertical axis corresponds to the frequency of certain feature values.
Similar to the gray histogram window, you can visualize the selected regions, i.e., the regions whose area falls between the values Min and Max, which are represented by the green and red vertical lines, respectively. Click the icon next to the selected feature (area) to enable the visualization.
Specify the parameters in the Output section of the feature histogram window as shown in
on page
see that in order to cover all the clips, we can safely select regions whose area is between, say, 4100 and the maximum value in the histogram. When you are satisfied with the selection, click the button Insert
Code. The following line (with similar numeric values) will be added to your program at the position of the IC: select_shape (ConnectedRegions, SelectedRegions,
'area', 'and', 4100, 5964)
Run the program, and inspect the output variable SelectedRegions. The regions corresponding to the clips are now determined correctly. To obtain the orientation and the center of gravity of the clips, add the following operator calls to the program: orientation_region (SelectedRegions, Phi) area_center (SelectedRegions, Area, Row, Column)
The operator orientation_region returns a tuple of values: For each region in SelectedRegions a corresponding orientation value in Phi is returned. The operator area_center in the same way returns the area, row and column of each input region as tuples. Again, run the program and inspect the calculated control variables. You can inspect multiple control variables in one inspection window. This is especially useful if the control variables all relate to each other as in this example. In the variable window select all control variables (hold down the <Ctrl> key), and right-click Inspect (see
Figure 4.10: Inspecting control variables.
4.13 Looping Over the Results
4.13
Looping Over the Results
Being an integrated development environment, HDevelop provides features found in other programming languages as well: Variable assignment, expressions, and control flow. Variable assignment and control flow are implemented in terms of specific HDevelop operators. These operators can be selected from the menu Operators . Control. Expressions are implemented in terms of a specific HDevelop language which can be used in input control parameters of operator calls.
To iterate over the elements in Phi, we use a for loop which counts from zero (the index of the first element of a tuple) to the number of elements minus one. The for loop is entered just like a common
HALCON operator: Enter for into the operator window and specify the parameters as in
The notation |Phi| - 1 is part of the HDevelop language. This operation calculates the number of elements in Phi minus one. When inserted in the program window, the operator for is displayed in a different format to make it more readable. Note that the closing endfor is entered automatically if the corresponding check box is ticked. Also note that the IC is placed between the added lines so that the body of the loop can be entered.
41
Figure 4.11: Entering a loop in HDevelop.
42 Programming HDevelop
Add the following lines to the program. They are automatically indented in the program window to highlight the nesting inside the for loop.
set_tposition (3600, Row[Index], Column[Index]) write_string (3600, deg(Phi[Index]) +
' degrees')
The instruction set_tposition places the text cursor in the active graphics window at the center of the region corresponding to the loop index variable Index. The value 3600 is the so-called window handle of the target graphics window. This number is displayed in the title of the graphics window and can be different in your environment. The notation Row[Index] is another operation of the HDevelop language. It provides access to a single value of a tuple.
The instruction write_string outputs a given string at the current text cursor position in the graphics window. The function deg is part of the HDevelop language. It converts its argument from radians to degrees. In this example the operation + performs a string concatenation because the argument
’ degrees’ is a string value. Before the two operands of + are concatenated, an automatic type conversion (double to string) of the numeric argument takes place. The details of the HDevelop language are explained in
on page
4.14
Summary
This is basically the way to create programs in HDevelop. Select an operator, specify its parameters, try different settings using the button Apply, add a new program line using Enter or OK, and edit it later by double-clicking it in the program window. Use the interactive tools provided by HDevelop to assist you, e.g., to find appropriate values for the operators.
Graphical User Interface 43
Chapter 5
Graphical User Interface
This chapter is the reference to the graphical user interface of HDevelop.
5.1
Main Window
The main window handles HDevelop programs. It comprises the following components:
Window Title
The main window of HDevelop is identified by the title HDevelop followed by the name of the current program (or unnamed if no file name has been specified yet). Unsaved changes in the current program are indicated with a trailing asterisk (*) in the window title.
Menu Bar
The menu bar at the top provides access to the functionality of HDevelop. The menus and their entries are described in the section “Menu Bar” on page
Tool Bar
The tool bar icons provide convenient shortcuts for frequently used functions. It is described in the section “Tool Bar” on page
44 Graphical User Interface
Window Area
The main part of the window is reserved for the windows and dialogs of HDevelop. The most important windows are the following:
• Program window (see page
• Operator window (see page
• Variable window (see page
• Graphics window (see page
• Online help window (see page
Status Bar
The status bar at the bottom of the main window displays status information, e.g., context-sensitive information about a specific user action or the runtime of operator or procedure calls (unless time measurement has been deactivated in the preferences, see section “Runtime Settings -> Runtime Settings” on page
The status bar is divided into the following five areas (from left to right, see
1. Status icon: Shows the current run status of the program.
2. Messages and runtime information. For example, if you select an operator from the menu, the corresponding short description is displayed here.
The runtime information depends on the run mode: When single-stepping through the program, the runtime of the last operator or procedure call is displayed. In continuous run mode, a runtime summary of the executed program lines is displayed when the program stops. A history of the most recent messages is also kept, see below.
3. Information about the image in the active graphics window. The display format is
[index] variable name (#=number of objects: height x width x channels x type)
4. Gray value of the image in the active graphics window at the mouse cursor position. For multichannel images, the gray values of all channels are displayed separated by commas.
5. Image coordinates in the graphics window (row, column).
run status messages / runtime information image details
Figure 5.1: The status bar.
gray value coordinates
5.1 Main Window
The status bar has its own context menu:
You can toggle whether execution messages are displayed in the status bar by clicking the entry Show
Processing Time in the context menu of the status bar. To open the context menu, right-click in the message area of the status bar.
A history of the latest execution messages is displayed as a tool tip when placing the mouse pointer over the message area of the status bar. The history can be copied to the clipboard by selecting the entry Copy
History to Clipboard in the context menu of the status bar.
Window Modes
There are two different window modes in HDevelop, which can be toggled in the menu Window:
MDI (multiple-document interface): In this mode the main window contains all other windows and dialogs (with the exception of the online help window and modal dialogs which block other windows temporarily). You are free to move the windows according to your needs and preferences inside the main window. You may iconify and/or deiconify them. HDevelop provides basic window management functions in this mode.
SDI (single-document interface): In this mode the main window contains only the menu bar, the tool bar, the status bar, and the program window. All other windows are independent. You may find this mode beneficial if you want to take advantage of special window manager capabilities under
UNIX.
45
46 Graphical User Interface
5.2
Menu Bar
The menu bar of the main window provides access to the complete functionality of HDevelop. Here, you may choose HALCON or HDevelop operators or procedures, or manipulate the graphical output. Every menu item opens a pull-down menu (henceforth abbreviated as menu) with optional submenus. You open a menu by clicking a menu item or via the keyboard (by pressing the <Alt> key in combination with the underlined letter of the menu item). In the following sections the menu entries are described in the order in which they appear.
5.2.1
Menu File
This menu provides functions to load images and existing programs and to save recently created or modified programs and procedures, respectively. Furthermore, you may export HDevelop programs to
C++, C, Visual Basic, Visual Basic .NET, or C#, and also print them.
5.2.1.1
New Program
Synopsis: Initialize a new HDevelop program.
Checks for:
(page
Shortcut: <Ctrl+N>
This menu item deletes the current program including all local procedures. The contents of variables are deleted before removing them. In addition, all graphics windows except one are closed. The last graphics window is cleared. The display parameters for the remaining graphics window are reset to the default values stored in the preferences (see section “Visualization Settings -> Pen / LUT / Paint” on page
Settings -> Runtime Settings” on page
5.2.1.2
Open Program...
Synopsis: Load an existing HDevelop program.
Checks for:
(page
Shortcut: <Ctrl+O>
A
(page
155 ) pops up to select an HDevelop program. Please note that only native
HDevelop programs can be loaded. Thus, text, C, C++, Visual Basic, Visual Basic .NET, and C# versions of a file are rejected.
After you have loaded a program, the corresponding file name is added to the top of the menu Recent
Programs. This allows you to quickly switch between recently loaded programs.
5.2.1 Menu File
5.2.1.3
Browse Examples...
Synopsis: Load HDevelop example program by selecting it from a categorized list.
Checks for:
(page
Shortcut: <Ctrl+E>
Selecting this menu item opens a dialog that allows you to load HDevelop example programs grouped by categories. The dialog is displayed in
Browsing the Categories
The tree on the left contains a structured list of categories. Clicking the icon in front of a category toggles the display of its children. Alternatively, double-clicking any category label shows and hides the subcategories while also selecting the node of the tree. There can be multiple levels of categories. If you select a category, all its matching example programs are listed in the area on the right. You can select multiple categories by holding down the <Ctrl> key while clicking additional categories. An HDevelop example program may appear multiple times under different topics and categories.
Filtering the Matched Example Programs
Both the file name and the short description of the matched example programs are displayed. You can reduce the number of listed programs by entering a search string into the Filter text box. As you type, the list is updated to contain only example programs matching the string in either the file name or the short description field. The filtering is case-insensitive.
47
Figure 5.2: Browse Examples....
48 Graphical User Interface
Loading an Example Program
Double-click an example program in the list, or select it and click the button Open. Clicking Open in new HDevelop opens the program in a new instance of HDevelop, which is useful if there are unsaved changes in the current program.
Either way, you can keep the dialog open by checking the corresponding box beforehand. This can be useful if you wish to scan through several example programs quickly.
5.2.1.4
Recent Programs
Synopsis: Load recently used HDevelop programs.
Checks for:
(page
This submenu contains a list of the most recently used HDevelop programs. Simply click on a program name to load it. This menu may be customized in the preferences (see General Options -> General
Options).
5.2.1.5
Insert Program
Synopsis: Insert (parts of) another HDevelop program into the current program.
Selecting an entry in this submenu opens a
(page
155 ) for the selection of an HDe-
velop program.
2 Insert All...
Synopsis: Insert a complete HDevelop program into the current program.
The main procedure of the selected program is inserted at the IC. All local procedures of the selected program are copied to the current program under their original name. If a local procedure of that name already exists, the suffix _COPY_1 (or _COPY_2, _COPY_3... for subsequent imports) is added to the imported local procedure. All invocations of the renamed procedure are updated automatically.
If the current program already contains an external procedure with the same name, the imported local procedure overrides the external procedure.
2 Insert Procedures...
Synopsis: Insert local procedures of the selected program into the current program.
Via this menu item you can add local procedures from an HDevelop program to the current program.
All local procedures except the main procedure are loaded from the selected file. If the current program already contains a local procedure with the same name, the newly added procedure will be renamed by appending the suffix _COPY_1 to its name. If the current program already contains an external procedure with the same name, the newly added local procedure overrides the external procedure.
5.2.1 Menu File
2 Insert Mainbody...
Synopsis: Insert only the main procedure of the selected program into the current program.
Insert the main body of the selected program at the IC. No local procedures are imported. If the current program does not provide the procedures used in the imported program, the corresponding program lines are marked as invalid code and will not be executed. Invalid code is turned into valid code by providing the missing procedures.
5.2.1.6
Save
Synopsis: Save changes of the current HDevelop program or the currently selected external procedure.
Shortcut: <Ctrl+S>
The actual functionality of this menu entry depends on the selected procedure in the program window:
• Main or local procedure selected in program window:
Save changes of the current HDevelop program. If no file name has been specified yet, a
(page
155 ) will be opened. Local procedures are saved within the HDevelop
program.
The file name of the program you save is added to the menu Recent Programs.
Please note that modified external procedures are not saved automatically. To save them as well, select the menu entry Menu File . Save All, or select the corresponding external procedure in the program window and click Menu File . Save again (see below).
• External procedure selected in program window:
Save changes to the currently selected external procedure back to the originating file. The operation is done quietly. A modified external procedure is marked with an asterisk (*) in the program window.
If you try to save a file that has been modified outside of your running instance of HDevelop (possibly by another user), a warning message is displayed asking whether you want to overwrite the file. If you are uncertain about the external changes to the file, it is recommended to click No, and save your program under a different name using Save Program As....
5.2.1.7
Save Program As...
Synopsis: Save changes of the current HDevelop program to a new file.
Shortcut: <Ctrl+Shift+S>
A
(page
155 ) is opened. You can specify a new file name and save the current
program under that name. The new file name becomes the default name of the current program so that subsequent Save operations will use that name instead of the old.
The file name of the program you save is added to the menu Recent Programs.
49
50 Graphical User Interface
5.2.1.8
Save Procedure As...
Synopsis: Save current procedure as an external procedure or as a stand-alone HDevelop program.
Using this menu entry you can save the currently selected procedure as an external procedure or an
HDevelop program. A
(page
155 ) is opened where you can select the file type:
• HDevelop procedures (*.dvp)
The procedure is saved as an external procedure. If the target directory is not already configured in the external procedure directories (see Menu Edit . Preferences...,
(page
66 )), HDevelop will suggest adding the directory to the list. An example dialog is displayed in
. If you click No, HDevelop will not be able to access the saved procedure unless the
directory is later added to the external procedure locations manually.
This is one method to make an internal procedure external. If you do not change the name of the procedure, the internal procedure will conceal the external procedure.
Figure 5.3: Adding a new directory to the list of external procedure directories.
• HDevelop local procedure (*.dev)
If this file type is selected, an empty main procedure is added to the target file, and the procedure is added to the program as a local procedure.
This menu item is disabled if the main procedure is selected in the program window.
5.2.1.9
Save All
Synopsis: Save the current program and all modified external procedures.
Shortcut: <Ctrl+Alt+S>
If no name has been specified for the current program yet, the behavior is similar to that of Save
Program As.... In addition, all modified external procedures marked with an asterisk (*) in the program window’s combo box are saved.
5.2.1 Menu File
5.2.1.10
Export
Synopsis: Export program code to a programming language or as a text file.
See also: hdevelop -convert (command line switch)
Using this dialog, you can select an export format and write (parts of) the current program to a file in that format. The dialog is displayed in
The button next to the export file name opens a
(page
155 ) to select a file name and
an export format. The following formats are supported (file extensions in parentheses):
• Text file (.txt)
• C (.c) . see also
on page
• C++ (.cpp) . see also
on page
• C# HALCON/.COM (.cs) . see also
on page
• C# HALCON/.NET (.cs) . see also
on page
• Visual Basic 6.0 HALCON/COM (.bas) . see also
on page
• Visual Basic .NET HALCON/COM (.vb) . see also
on page
• Visual Basic .NET HALCON/.NET (.vb) . see also
on page
The file name extension corresponding to the selected export format is appended to the specified file name.
51
Figure 5.4: Export.
52 Graphical User Interface
Print Range: The export range specifies which parts of the current program are exported. The following options are available:
• Program: The entire program is exported (main procedure and all local procedures). All used external procedures are exported depending on the setting of the external procedure options (see below).
• Current Procedure: The current procedure and all used local procedures are exported.
All used external procedures are exported depending on the setting of the external procedure options (see below).
• External Procedures: All external procedures are exported depending on the setting of the external procedure options (see below).
The short description and chapter information of procedures are exported as comments. Arbitrary code can be embedded with special comment lines (see
on page
Procedure Options: Defines the export behavior for external procedures.
• Export Procedure Body: Determines whether only the procedure declaration or both the declaration and the procedure body is exported.
Window Export: Specifies the export behavior of HALCON windows:
• Use HALCON Windows: Export as a stand-alone project.
• Use Export Template (HALCON/.NET and HALCON/COM only): Export as a project using the supplied project template.
Encoding: Specifies the encoding of exported programs. The following options are available:
• Native: Export in the encoding defined by the operating system.
• UTF-8: Force export in UTF-8 encoding (Unicode).
Keep dialog open: Checking this box keeps the dialog open for subsequent exports.
5.2.1.11
Read Image
Synopsis: Read an image from a selected directory.
See also: read_image
This submenu contains several directories from which images can be loaded. The directory denoted by . (a single dot) is the current working directory of HDevelop, i.e., the directory HDevelop was started from. Below that entry, the directories specified by the environment variables HALCONROOT and
HALCONIMAGES are displayed.
Directories below the separator line are user-defined directories. Each time an image is loaded from a directory which is not already listed, that directory name is appended to the menu. This is convenient when several images from a non-standard directory must be read.
When clicking on an entry in this menu, a
(page
155 ) of the given directory is opened.
Depending on the operating system you may be able to switch to a thumbnail view in this dialog. See
for an example.
5.2.1 Menu File
53
Figure 5.5: Read Image.
After selecting a file name, the dialog Read Image is opened. It displays a thumbnail of the selected image and some image properties. This is also displayed in
. HDevelop suggests a variable
name derived from the selected file name. You may adopt or edit this name. If you want to use a name of an already created iconic variable, a combo box offers you all known iconic variable names. Simply click the arrow on the right side of the combo box to select a variable name. Note that the reuse of a variable deletes the old content and replaces it with the new image.
Click OK to load the image into HDevelop. The operator read_image is inserted at the specified insert position (IC or PC). The specified iconic variable is updated in the variable window and the image is displayed in the active graphics window. Clicking Cancel aborts the operation.
5.2.1.12
Cleanup
Synopsis: Clean up allocated resources that are no longer being used.
See also:
variable window . context menu
(page
This menu item deletes all unused variables (iconic and control data) from the current procedure. These are variables in the variable window that are no longer used in any operator or procedure call in the current procedure body. This can happen after the deletion of program lines or after editing variable names, because the corresponding variables are not deleted automatically. You may use this menu item during a longer editing session to reorganize your
(page
54 Graphical User Interface
5.2.1.13
Properties...
Synopsis: Display various properties of the current program.
The tab card General displays file properties of the current program, such as file name, path, creation and modification date, and write permission. It also shows the file size, the number of lines of code, used and unused local procedures, used external procedures and used protected procedures. This is displayed in
Figure 5.6: Properties: General (left), Used Modules (right).
The tab card Used Modules lists the HALCON modules used by the current program. Modules marked with a lit bulb are used. This window allows you to get an estimate of how many modules your application will need in a runtime license. Please refer to the Installation Guide for more information about modules and runtime licenses. See
for the corresponding dialog of an OCR example.
Check only used procedures If checked, only used procedures are considered for the evaluation of the used modules. Otherwise, all procedures are considered.
Copy to Clipboard Copy the names of the used modules to the system clipboard. This way the list can be easily pasted into other applications.
5.2.1.14
Synopsis: Print the current program or selected procedures.
Shortcut: <Ctrl+P>
The print dialog is displayed in
Print Range
5.2.1 Menu File
55
Figure 5.7: Print.
Program: Complete program including all procedures.
Current Procedure: Current procedure and its used procedures.
Selection: Highlighted program lines and their used procedures.
External Procedures: All external procedures.
Procedure Options
Print Procedures: Define whether procedures are printed or not.
• Used Local Procedures: print only used local procedures.
• All Local Procedures: print all local procedures.
• Used External Procedures: also print used external procedures.
Only Procedure Interface: If this box is checked, the procedure body is not printed. Instead, only the interface of the procedure is printed.
The bodies of external procedures that are locked by a password (see section “Protected External Procedures” on page
5.2.1.15
Quit
Synopsis: Quit HDevelop.
Checks for:
(page
Shortcut: <Ctrl+Q>
See also: exit
This menu item terminates HDevelop.
56 Graphical User Interface
5.2.2
Menu Edit
In this menu you find all necessary functions to modify the current HDevelop procedure body displayed in the program window. Furthermore, a comprehensive find and replace functionality is offered. You can also access the preferences of HDevelop from this menu.
5.2.2.1
Undo
Synopsis: Undo your previous editing activities.
Shortcut: <Ctrl+Z>
You may undo your previous editing activities via this menu item. For example, by selecting it three times you cancel the last three editing actions. The menu entry always states the last editing action that will be undone, e.g.,
Undo Insert Program line at 23 (read_image)
The undo functionality purely applies to editing activities. No file operations will be undone. Thus, if you create an external procedure from some selected lines and undo the operation, the external procedure will not be removed from the file system.
The undo item does not work for the password assignment for external procedures (see section “Protected
External Procedures” on page
123 ). To undo the password assignment you either have to remove the
password as long as you can edit the procedure, or you quit HDevelop without saving the corresponding procedure.
5.2.2.2
Redo
Synopsis: Revoke undo activities.
Shortcut: <Ctrl+Y>
This is a quick way to restore the state before the last undo operation. The menu action explicitly states the last Undo action that will be revoked.
5.2.2.3
Cut
Synopsis: Cut the highlighted program lines in the program window to an internal buffer.
Shortcut: <Ctrl+X>
The highlighted program lines are removed from the selected procedure and placed in an internal buffer for later use. Additionally, for every procedure call the corresponding procedure and all procedures that can be reached from it are copied to the buffer. This is necessary in order to obtain a consistent program when pasting procedure call lines to a program in which the corresponding procedures might not exist.
The highlighted program lines are also copied to the system clipboard.
5.2.2 Menu Edit
5.2.2.4
Copy
Synopsis: Copy the highlighted program lines from the program window to an internal buffer.
Shortcut: <Ctrl+C>
The highlighted program lines are copied to an internal buffer without affecting the program. Additionally, for every procedure call the corresponding procedure and all procedures that can be reached from it are copied to the buffer. This is necessary in order to obtain a consistent program when pasting procedure call lines to a program in which the corresponding procedures might not exist. The highlighted program lines are also copied to the system clipboard.
5.2.2.5
Paste
Synopsis: Insert text into the currently selected procedure at the IC.
Shortcut: <Ctrl+V>
You can insert code lines from previous Cut or Copy operations or text placed in the system clipboard into the current procedure. The insert position depends on the editing mode: In the dialog-based editor, valid code lines from the paste buffer are inserted at the IC. In the full text editor, the text from the paste buffer is inserted at the text cursor position.
The following functionality is only available in the dialog-based editor: If the paste buffer contains local procedures that do not exist, they are added to the current program. If the paste buffer contains calls to external procedures, the paths to those procedures are copied, too. However, before an external procedure path is added during a paste action, you are asked whether or not you want to add that particular path to the external procedure paths. The mechanism of copying and pasting procedure calls together with the corresponding procedures is an easy way to transfer procedures between different HDevelop programs. It also works between multiple instances of HDevelop. The contents of the internal buffer are kept, allowing this command to be repeated.
5.2.2.6
Delete
Synopsis: Delete the highlighted program lines from the program window.
Shortcut: <Del>
This menu item deletes all highlighted program lines without storing them in an internal buffer. The only way to get the deleted lines back into your program body is to use the menu item Undo.
5.2.2.7
Activate
Synopsis: Uncomment the highlighted program lines.
Shortcut: <F3>
All of the highlighted program lines that were previously commented using the Deactivate command are converted back to executable code. Comment lines created with the operator comment are unaffected by this command.
57
58 Graphical User Interface
5.2.2.8
Deactivate
Synopsis: Comment out the highlighted program lines.
Shortcut: <F4>
The highlighted program lines are converted into comments. This is a quick way to suppress the execution of portions of the program for testing purposes. Comment lines created with the operator comment are unaffected by this command.
During testing, it is often useful to prevent some lines of the program from being executed. This can be achieved by selecting the appropriate lines in the program window and then selecting Deactivate. An asterisk is placed at the beginning of the selected lines, i.e., the lines appear as comments in the program window and have no influence on the program during runtime.
The deactivated lines are still part of the program, i.e., they are stored like all other lines and their variables are still needed like all other variables. To reverse this action, select Activate.
Note that you can insert a real comment into your program by using the operator comment
.
5.2.2.9
Find/Replace...
Synopsis: Find and replace text in the current program.
Shortcut: <Ctrl+F>
This dialog provides comprehensive facilities for searching the program code. You can perform a full text search or search for variable names as well as operator (or procedure) calls. In addition, you can replace variable names and substitute operator or procedure calls. The dialog is displayed in
Figure 5.8: Find/Replace.
5.2.2 Menu Edit
The search context can be set to one of the following entities:
Variables: Find program lines with variable names that match the search text.
Operators: Find program lines with operator or procedure calls that match the search text.
Texts: Full text search. Find program lines that match the search text anywhere. If the full text editor is disabled, no replacing is allowed in this mode to ensure the consistency of the program code.
The search scope can be specified as follows:
All: Search the main procedure, all local and all external procedures.
Program: Search the main procedure and all used procedures.
Current Procedure: Search the current procedure only.
Please note that locked procedures are not searched (see section “Protected External Procedures” on page
The following parameters specify how the search is performed:
Case Sensitive: By default, the case of the search text is ignored, thus searching for image will find
Image or IMAGE as well. Check this box to make the search case-sensitive.
Whole Words: By default, program lines are matched even if the search text is only part of a word, thus an operator search for threshold also matches operator calls to bin_threshold. Check this box to find only exact matches.
Backward: Check this box to reverse the search direction.
Finding Single Occurrences of the Search Text
Enter the search text and click Find. If there is no match, the text field will blink shortly. Otherwise, the first matching program line in the current procedure is highlighted. Each subsequent click of Find highlights the next matching program line. If the last matching line of the current scope has been reached, the text field blinks shortly. The next click on Find starts over at the beginning.
Finding All Occurrences of the Search Text
Enter the search text and click Find All. All matched lines are listed at the bottom of the dialog along with the corresponding procedure name and line number. Click on a search result to jump to the corresponding procedure and highlight the matching program line. This function is recommended before doing a global replace to preview which program lines will be affected. An example is displayed in
You can even select multiple lines from the search result by holding the <Ctrl> key. The following actions may be performed for all selected lines (either from the context menu of the search result or the corresponding menu entries or tool bar icons):
(page
(page
(page
(page
(page
59
60 Graphical User Interface
Figure 5.9: Finding all occurrences of the search text.
Replacing Variable Names
Click Variables to specify the search context. Enter the search text and the replace text. You can replace parts of variable names by keeping Whole Words unchecked.
Click Find until the desired line is found. Afterwards, click Replace to replace all occurrences of the search text in the matched line. The next matching line is highlighted automatically.
Click Replace All to replace all occurrences of the search text in the specified scope. It is recommended to do a Find All beforehand, to estimate the extent of this operation.
Replacing Operator Calls
You can replace one operator or procedure call with another. Because different operators very likely have different parameters, the source parameters have to be mapped to the target parameters beforehand. See
for an example.
Click Operators to specify the search context. Enter the source operator or procedure name and the target operator or procedure name. When both names are specified, the parameters of the target operator/procedure are listed at the bottom of the dialog. For every target parameter you have to select or enter a corresponding source parameter.
Figure 5.10: Replacing operator calls.
5.2.2.10
Find Again
Synopsis: Find the next match of the last entered search string.
Shortcut: <Ctrl+G>
This menu item repeats the search specified via the menu item Find/Replace....
5.2.2 Menu Edit
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62 Graphical User Interface
5.2.2.11
Preferences...
Synopsis: Set global preferences of HDevelop.
HDevelop maintains a set of preferences that are persistent between sessions. You can customize the appearance of HDevelop’s user interface (syntax highlighting, fonts, and language) as well as its behavior, configure the settings of external procedures, and change the default visualization settings of the graphics windows.
Changes to the settings in this dialog are saved automatically without any user intervention. The location of the generated file depends on the operating system:
Windows: %APPDATA%\MVTec\HDevelop.ini
UNIX: $HOME/.hdevelop/MVTec/HDevelop.ini
The dialog provides its own menu with the following entries:
Import Using this menu entry you can import a selection of preferences which were previously saved using the menu entry Export (see below). The dialog is displayed in
In the import dialog you can select a file with saved HDevelop preferences (default file extension:
.hdp). The check boxes allow to import groups of settings selectively. They correspond to the categories of the dialog. The runtime settings are not persistent and can neither be exported nor imported.
Export The export dialog is identical to the import dialog. Using the check boxes you can specify which settings will be saved to the selected file.
Reset Selecting this menu entry resets all preferences (except the window geometry and layout) to the default settings. If you want to reset the window geometry as well you can start HDevelop with the following command line switch:
Figure 5.11: Import.
5.2.2 Menu Edit hdevelop -reset_preferences
The preferences dialog contains a list of categories on the left and several related tab cards on the right.
The size and orientation of these elements are controlled by a splitter. The available categories of preferences are described in the following sections.
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64 Graphical User Interface
2 User Interface . Program Listing
Font: Specifies the font that is used in the program window.
Indent Size: Specifies the number of spaces an indenting level in the program window accounts for.
In HDevelop the bodies of loops and conditionals are indented automatically.
Colors: Specifies the colors used for syntax highlighting in the program window. You can choose one of the predefined color schemes, or set up your own by clicking on the colored buttons. Changing any color automatically switches to the color scheme User defined.
Editor Settings: HDevelop supports two methods for editing programs:
• Dialog-based Editor
Specifies the classical dialog-based editing mode. In this mode, program lines are edited in the operator window by double-clicking them in the program window. This editing mode is described in the section “Dialog-based Editor” on page
• Full Text Editor
Selects the full text editor. In this mode, text can be freely edited in the program window.
Double-clicking in the program window still sends the corresponding program line to the operator window (unless the operator window has been closed). This way, the full text editor can be used in conjunction with the classical dialog-based editing mode. This editing mode is described in the section “Full Text Editor” on page
If the full text editor is selected, the following option tweaks its operation:
• Advanced Autocompletion
Enables advanced autocompletion in the full text editor. This feature is described in the section “Full Text Editor” on page
These options can also be set in the program window (see section “Program Window Tool Bar” on page
2 User Interface . Fonts
In this tab card, the font settings of HDevelop may be modified.
• General: The font used throughout the user interface (menu entries, labels etc.)
• Help Window: The body font used in the help window (menu
(page
• Program Listing: The font used in the program window. This is the same font setting as on the tab card Program Listing (see above).
• Advanced Autocompletion: The font used in the advanced autocompletion overlays.
• Values and Parameters: The font used for displaying values in the variable window and associated inspection windows as well as parameters in the operator window.
• Printing: The font used when printing program listings.
5.2.2 Menu Edit
65
Figure 5.12: User Interface . Program Listing.
2 User Interface . Language
In this tab card you can change the language of the user interface. Please note that HDevelop needs to be restarted if a different language is selected. By default, HDevelop uses the language that is specified in the operating system locale (specifically, the environment variable LC_COLLATE). Once the language is changed in this dialog, the operating system locale is disregarded.
2 User Interface . Layout
Show full path in main window title: This check box determines whether the full path of the current program or only the file name is displayed in the title bar of the HDevelop window.
Default for Organize Windows: These combo boxes define the tiled layout of the four main windows of HDevelop when using the menu entry Menu Window .
(page
66 Graphical User Interface
2 External Procedures . Directories
Use this tab card to manage the list of directories that contain external procedures. The directories are scanned for external procedures in their listing order. For each directory, the total number of procedures is displayed. The number of loaded procedures is usually equal to the total number. However, external procedures are not loaded if a directory contains procedures with the same name as a preceding directory.
The tab card is displayed in
Please note that HALCON comes supplied with a set of standard procedures. These are general-purpose procedures used by many of the supplied example programs. The path to these external procedures is set to %HALCONROOT%\procedures under Windows and $HALCONROOT/procedures under UNIX, and cannot be altered or deleted in this dialog. It is, however, possible to override the supplied external procedures by placing external procedures with the same name in one of the user-defined directories.
The documentation of the supplied procedures is available in the online help of HDevelop under Procedure Reference Manual.
Figure 5.13: External Procedures . Directories.
Add: Select an additional directory from the
(page
added to the list. All subdirectories of the selected directory will be scanned as well.
Delete: Delete the selected directory from the list. Programs using any external procedure from that directory will no longer run.
Rescan: Rescan all listed directories to reflect any changes in the file system.
5.2.2 Menu Edit
2 External Procedures . External Procedures
This tab card lists all external procedures in the order they are loaded from the
(page
66 ). For each procedure, the following information is displayed:
Field
#
Procedure Name
State
Meaning
Number of the external procedure.
Name of the external procedure.
Loaded : The external procedure has been loaded successfully. It can be used in any HDevelop program.
Unloaded : An error occurred while trying to load the external procedure, e.g., the file permissions are wrong or the external procedure file is corrupted.
Relative Path
Used by
Hidden : An external procedure with the same name has already been loaded from a different directory.
Search Directory
Directory name from the tab card Directories where this procedure is found.
Path name of the external procedure relative to the search directory.
Usage counter and the names of the callers of this procedure.
Modifications
The number of modifications to the external procedure after it has been loaded.
67
Figure 5.14: External Procedures . External Procedures.
68 Graphical User Interface
2 External Procedures . Manage Passwords
Using this tab card, you can conveniently manage the editing status and passwords of all external procedures. The external procedures are divided into three categories (from left to right): External procedures without a password (unprotected), external procedures for which the password has already been entered in this session (unlocked), and external procedures that are locked with a password. For an explanation of the different states, see section “Protected External Procedures” on page
Using the arrow buttons between the columns or the left and right cursor key, you can move the selected external procedures to a different status. If you move procedures from the first to the second column, a password dialog is displayed which is described in section “Protecting a Procedure” on page
same password is applied to all selected procedures.
If you move procedures from the second to the third column, the bodies of the corresponding external procedures will be locked. They can only be accessed if the correct password is supplied. This can either be done from this dialog by simply moving the corresponding procedures back to the middle column and entering the password. Or, you can unlock procedures individually from the program window as described in section “Creating and Editing Procedures” on page
If you select multiple procedures in the third column and move them to the left, a password dialog appears to unlock the procedures. Only those procedures are moved (and thus unlocked) that match the supplied password. This way, you can conveniently edit a group of external procedures that share the same password.
The button Change Password is available if one or more procedures are selected in the middle column.
It assigns a new password to the selected procedures, regardless if the previous passwords were different.
Please note, that password changes or moving procedures from or to the first column require the corresponding procedures to be saved. See
(page
(page
Figure 5.15: External Procedures . Manage Passwords.
5.2.2 Menu Edit
69
Figure 5.16: External Procedures . Procedure Use.
2 External Procedures . Procedure Use
This tab card lists the usage of procedures grouped by their calling procedures. You can select a procedure and the type of used procedures (either local or external). For the main procedure you can also list the unused procedures. The tab card is displayed in
2 External Procedures . Unresolved Procedure Calls
This tab card helps you to find unresolved procedures in your current program. If the current program or the loaded procedures contain unresolved procedure calls, they are listed here along with the calling procedure name.
70 Graphical User Interface
2 General Options . General Options
• Select the behavior of pressing the [Return] key in the operator window or full text editor:
This option can also be set in the program window (see section “Program Window Tool Bar” on page
• OK (Enter and execute): Enter the operator in the program window and execute it (the default behavior).
• Enter: Enter the operator without executing it.
• Save program and external procedures automatically before execution:
If this option is enabled and you click any of the execution buttons (like Run or Step Over) and there are unsaved changes in the current program, the program will be saved before being executed.
Use this option with care: You usually do not want to select this option if you are experimenting with a program, e.g., when trying out different parameter settings.
• Number of recent program files:
The number of recent program files that are displayed in the menu Menu File . Recent
Programs can be adjusted by altering this value.
• Show recent program files:
If you select the option Only available, the list of recent programs contains only programs that are currently available. This option is useful, if the list is likely to contain files from network drives that might be disconnected at times.
• Encoding for saving HDevelop programs and procedures:
HDevelop can save programs and procedures in two different encodings. Upon loading, HDevelop detects the used encoding automatically. It is recommended to use UTF-8 encoding (Unicode) if the program contains international characters that exceed the ASCII standard. However, in order to load programs in older versions of HDevelop, you have to set the encoding to Native.
• Precision for displaying real values:
This option sets the number of significant digits that are displayed in the
(page
129 ) and variable inspection windows, see “Inspecting and Editing Variables” on page
• Display string values with special characters quoted:
Special characters (like \n for a newline character) in string values are usually interpreted in the variable window and the variable inspect window. If this option is ticked, special characters are displayed verbatim, i.e., as they are entered. See
on page
for a list of special characters.
• Precision for displaying mouse position values:
If set to a value greater than 0, subpixel mouse positions are enabled. See
(page
5.2.2 Menu Edit
2 General Options . Experienced User
• Show HALCON Low Level Error Messages:
Low-level errors are normally invisible for the user because they are transformed into more comprehensive error messages or simply ignored. Activating this item generates a message box each time a low-level error occurs.
• Suppress error messages (throw directly an HDevelop exception):
HDevelop normally displays a dialog when a run-time error occurs (unless this has been changed in the tab Runtime Settings -> Runtime Settings). If an error occurs in a watched block of program lines (surrounded by try
...
catch
), the user may choose to cancel the program execution, or to throw an exception, i.e., continue the execution at the corresponding catch
...
endtry block.
Activate this option, if you always want exceptions to be thrown without any user intervention.
• Ignore semantic type:
By default, the parameter suggestions in the operator window and the full text editor (with advanced autocompletion enabled) include only variable names that match the semantic type of the corresponding parameter. If Ignore semantic type is checked, these suggestions are extended so that they also include suggestions of variables with a different semantic type.
• Show memory usage:
If this option is activated, the internal temporary memory usage of the last operator or procedure call is displayed in the status bar.
• Suppress warnings for HALCON operators that are replaced by dev-operators:
Some operators are deprecated in HDevelop, and issue a warning message when selected in the operator window. Activating this option suppresses the warning message.
• Disable parameter detection for acquisition operators:
In the operator window, the parameter suggestions for the operators open_framegrabber
, set_framegrabber_param
, and get_framegrabber_param depend on the selected image acquisition interface. This behavior can be disabled by ticking the check box. See also Parameter
Display on page
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72 Graphical User Interface
2 Visualization Settings . Pen / LUT / Paint
The tab cards in this category define the default visualization settings for graphics windows when HDevelop is started. See the description of “Set Parameters...” on page
84 . The dialog is displayed in
Figure 5.17: Visualization Settings . Visualization Parameters.
2 Runtime Settings . Runtime Settings
The settings in this category affect the runtime behavior of HDevelop. Please note that the runtime settings are not persistent between sessions. The runtime settings are reset to their default values, when a new HDevelop program is started with Menu File . New Program. The dialog is displayed in
Figure 5.18: Runtime Settings.
5.2.2 Menu Edit
Give Error See also: dev_set_check
This check box specifies the behavior of HDevelop if an error occurs. If it is checked, HDevelop stops the program execution and displays an error message. Otherwise the error is ignored.
Show Processing Time See also: dev_update_time
This check box indicates whether the required runtime of the last operator or procedure call should be displayed after the execution has stopped. It is a measurement of the needed time for the current operator or procedure call (without output and other management tasks of HDevelop). Along with the required runtime, the name of the operator or procedure is displayed in the status bar at the bottom of the main window. Please note that the displayed runtime can vary considerably. This is caused by the inaccuracy of the operating system’s time measurement procedure.
This option can also be toggled from the context menu of the status bar (see page
Update Program Counter See also: dev_update_pc
This option concerns the display of the current position while running the program. The PC always indicates the line of the currently executing operator or procedure call or the line before the next operator or procedure call to execute. Using the PC in this way is time consuming. Therefore, you may suppress this option after your test phase or while running a program with a lot of “small” operators inside a loop.
Update Variables See also: dev_update_var
This check box concerns the execution of a program: Every variable (iconic and control) is updated by default in the variable window. This is very useful in the test phase, primarily to examine the values of control data, since iconic data is also displayed in the graphics window. If you want to save time while executing a program with many operator calls, you may suppress this output.
Independent of the selected mode, the display of all variables will be updated after the program has stopped.
Update Graphics Window See also: dev_update_window
This item concerns the output of iconic data in the graphics window after the execution of a HAL-
CON operator. With the default settings, all iconic data computed in the run mode is displayed in the current graphics window. You may want to suppress this automatic output, e.g., because it slows down the performance or because the program handles the visualization itself. If the output is suppressed, you have the same behavior as exported C, C++, Visual Basic, Visual Basic .NET, or C# code, where automatic output of data is not supported.
Enable the Context Menu in the Graphics Window See also: dev_set_preferences
If this option is activated, the context menu is available when clicking in a graphics window with the right mouse button. This behavior may be undesirable if a program provides user interaction with the mouse.
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5.2.3
Menu Execute
In this menu item you find all necessary functions to execute an HDevelop program. In HDevelop, program execution is always continued at the top-most procedure call, which in most cases corresponds to the current procedure call. The procedure body displayed in the program window belongs to the current procedure.
5.2.3.1
Run
Synopsis: Execute the current program from the PC.
Shortcut: <F5>
The program line marked by the PC is the first line that is executed. All following program lines are going to be performed until the end of the current program. After the execution is finished, the main procedure becomes the current procedure. Note that a break point, stop instruction, or runtime error may interrupt the execution of your program. If the HDevelop program waits for the user to draw something in the graphics window, a notification message is printed in the status bar. The program halts until the user finishes the draw operation and confirms this by clicking the right mouse button.
During the execution of operator or procedure calls the following special behavior occurs:
• You may initiate limited activities. For example, if you double-click variables in the
(page
129 ) they will be visualized; you may modify parameters for the graphics windows
as described in the Menu Visualization; you may even modify the current procedure body.
Note that all user interaction except Stop is disabled during program execution in case the latter was not started in the main procedure. HDevelop may be slow to react to your actions while the program is running. This is caused by the fact that HALCON reacts to user input only between calls to operators.
• A variable window update during runtime will only be performed if it has not been suppressed (see section “Runtime Settings -> Runtime Settings” on page
72 ). In any case, the values of all
variables are shown in the variable window after the execution’s termination.
While the program is running, the menu items Run, Step Over, Step Into, and Step Out (and the corresponding tool bar buttons) are grayed out, i.e., you cannot execute them.
You have the following possibilities to stop your HDevelop program:
• The program runs until the last operator or procedure call in the current program (i.e., the main procedure body) has been called. The PC is positioned behind this operator. This is the usual way a program terminates.
• The menu Menu Execute . Stop (or the corresponding tool bar button) is pressed.
• A break point is reached (see section “Program Window” on page
operator or procedure call that will be executed is the one before the break point.
• The entry Menu File . Quit has been executed (see “Quit” on page
5.2.3 Menu Execute
• A runtime error has occurred. An input variable without a value or values outside a valid range might be typical reasons. In this case the PC remains in the line of the erroneous operator or procedure call.
• A stop instruction is executed. The PC remains on the line containing the stop instruction. Note that stop instructions inside protected external procedures (see “Protected External Procedures” on page
123 ) are obeyed. However, the code of the protected procedure will only be visible if the
correct password is entered in the program window.
The procedure and procedure call in which program execution was stopped automatically become the current procedure and procedure call.
5.2.3.2
Run to Insert Cursor
Synopsis: Run from PC to IC.
Shortcut: <Shift+F5>
The menu entry starts executing the program at the line next to the PC. The execution continues until the line before the IC is executed. Any break points or stop instructions in between cause the program execution to be stopped.
5.2.3.3
Step Over
Synopsis: Execute the next operator in the current program.
Shortcut: <F6>
This entry enables you to run a program (even if it is not complete) step by step. HDevelop executes the operator or procedure call directly to the right of the PC.
After the operator or procedure call has terminated, all computed values are assigned to their respective variables that are named in the output parameter positions. Their graphical or textual representation in the variable window is also updated. If iconic data has been computed, you will see its presentation in the active graphics window.
In the status bar the runtime of the operator or procedure call is indicated (unless the time measurement has been deactivated).
The PC is then moved to the next operator or procedure call to execute. If the operators or procedure calls are specified in a sequential order, this is the textual successor. In case of control statements (e.g., if
...
endif or for
...
endfor
), the PC is set on the end marker (e.g., endif or endfor
) after the execution of the last operator or procedure call inside the statement’s body. After endfor and endwhile
, the PC is always set on the beginning of the loop. If a condition (like if or while
) evaluates to FALSE, the PC is set behind the end marker.
Suggestions in the menu Menu Suggestions are determined for the recently executed operator. Finally,
HDevelop is available for further transactions. Any user input which has been made during execution is handled now.
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76 Graphical User Interface
5.2.3.4
Step Forward
Synopsis: Execute the next line in the current program.
Shortcut: <Shift+F6>
This entry always steps forward in the current program. The difference to Step Over is apparent in loops: Only the first run of the loop is single-stepped. When the closing statement of the loop is reached, the remaining runs of the loop are executed without interruption, and the line following the loop is executed stepwise again.
5.2.3.5
Step Into
Synopsis: Step into HDevelop procedure.
Shortcut: <F7>
This entry allows you to step into procedure calls. Executing Step Into with the PC on a procedure call line causes the corresponding procedure and procedure call to become the current procedure and procedure call, respectively. The PC is set on the first executable program line in the new current procedure.
Step Into has the same effect as Step Over if the program line to be executed is not a procedure call.
5.2.3.6
Step Out
Synopsis: Step out of HDevelop procedure.
Shortcut: <F8>
This entry steps out of the current procedure call. Program execution is continued until the first executable program line after the previous procedure call in the calling procedure is reached. The previous calling procedure becomes the current procedure. If the current procedure is the main procedure, the behavior is the same as Run.
5.2.3.7
Stop
Synopsis: Stop program execution.
Shortcut: <F9>
HDevelop continues processing until the current operator has completed its computations. This may take a long time if the operator is taking a lot of time to execute. There is no way of interrupting a HALCON operator. The procedure and procedure call in which the program execution was stopped becomes the current procedure and procedure call, respectively. After interrupting a program you may continue it by selecting Run or Step Over, or Step Into if the next program line is a procedure call.
You may also edit the program before continuing it (e.g., by parameter modification, by exchanging operators with alternatives, or by inserting additional operators).
5.2.3 Menu Execute
5.2.3.8
Call Stack...
Synopsis: Visualize the calling hierarchy.
Selecting this item depicts a dialog that contains a list of the names of all procedures that are currently called on HDevelop’s internal call stack. The top-most procedure call belongs to the most recently called procedure, the bottom-most procedure call always belongs to the main procedure. Clicking on a procedure call in the dialog makes the selected procedure call the current procedure call and thus the procedure belonging to the selected procedure call the current procedure.
When you click on a procedure call that belongs to a protected external procedure (for protected external procedures see “Protected External Procedures” on page
123 ), you can only see the procedure body if
you enter the correct password in the program window.
77
Figure 5.19: Call Stack.
5.2.3.9
Set Breakpoint
Synopsis: Add break point(s) at selected line(s).
This menu item sets a break point on the lines that are currently selected in the program. In most cases, however, it is more convenient to set individual break points by holding the <Ctrl> key and clicking in the left column of the program window as described in “Program Counter, Insert Cursor, and Break
Points” on page
5.2.3.10
Clear Breakpoint
Synopsis: Clear break point(s) at selected line(s).
These menu item clears break points on the lines that are currently selected in the program. In most cases, however, it is more convenient to clear individual break points by holding the <Ctrl> key and clicking in the left column of the program window as described in section “Program Counter, Insert Cursor, and
Break Points” on page
5.2.3.11
Clear All Breakpoints
Synopsis: Clear all break points in the current program.
78 Graphical User Interface
5.2.3.12
Reset Program Execution
Synopsis: Reset program to its initial state.
Shortcut: <F2>
The main procedure becomes the current procedure and the call stack is cleared of all procedure calls except the main procedure call. The latter is reset, i.e., all variables have undefined values and the PC is set to the first executable line of the main procedure. The break points, however, are not cleared. All graphics windows except one are closed, and the remaining graphics window is cleared. This menu item is useful for testing and debugging programs.
5.2.3.13
Reset Procedure Execution
Synopsis: Reset procedure execution.
Shortcut: <Shift+F2>
The variables of the current procedure are reset, i.e., all variables have undefined values, and the PC is set to the first executable line of the current procedure. This menu item is useful for debugging procedures without affecting the calling procedures.
5.2.3.14
Abort Procedure Execution
Synopsis: Abort execution of current procedure.
Shortcut: <Shift+F8>
All variables of the current procedure are reset. The PC is set back to the line in the calling procedure from which the current procedure was called. The calling procedure becomes the current procedure.
5.2.4 Menu Visualization
5.2.4
Menu Visualization
Via this menu, you can open or close graphics windows and clear their displays. Furthermore, you may specify their output behavior during runtime. Most functions are also available from the context menu of the graphics windows.
5.2.4.1
Open Graphics Window...
Synopsis: Open a new graphics window.
See also: dev_open_window
When selecting this menu entry, a dialog window pops up. Here, you may specify some graphics window attributes. The dialog is displayed in
. The position, size and background color of the new
graphics window can be specified. For example, it is more convenient to have a white background while building graphics for slides or reports (see the HALCON operator dump_window
). If the window height and width are set to -1, the window size is set by HDevelop. It is taken from the persistent preferences of
HDevelop (usually the size of the last graphics window in the previous HDevelop session). A position value of -1 specifies that the window position is determined by the window manager (in SDI mode).
79
Figure 5.20: Specifying the parameters of the new graphics window.
The window handle of the new graphics window is displayed in its title bar. This number may be used in operators that require a window handle (e.g., dev_set_window or dump_window
). The handling of graphics windows is described in more detail in the section “Graphics Window” on page
5.2.4.2
Clear Graphics Window
Synopsis: Clear active graphics window.
See also: dev_clear_window
The history (previously displayed objects) of the window is also cleared.
80 Graphical User Interface
5.2.4.3
Close Graphics Window
Synopsis: Close active graphics window.
See also: dev_close_window
5.2.4.4
Display
Synopsis: Select iconic variable to be displayed in active graphics window.
See also: dev_display
This submenu lists all instantiated iconic variables for quick selection. The submenu is split in three parts (from top to bottom): images, regions, and XLDs.
5.2.4.5
Window Size
Synopsis: Set window size of active graphics window.
See also: dev_set_window_extents
This submenu offers a list of fixed percentages to resize the graphics window with respect to the size of the most recently displayed image.
The entries Double and Half change the size of the graphics window to half and double its current window size, respectively, independent of the size of the displayed image.
The entry Aspect Ratio 1:11 scales down the current window size, so that the aspect ratio of the displayed image is maintained.
5.2.4.6
Image Size
Synopsis: Zoom image size of active graphics window.
The entry Fit Window scales the image to completely fill the graphics window.
A list of fixed percentages scales the image with respect to its natural size.
Double and Half double and half the current image size, respectively.
Aspect Ratio 1:11 scales down the image size, so that its aspect ratio is maintained.
5.2.4 Menu Visualization
5.2.4.7
Colored
Synopsis: Disambiguate the display of regions and XLDs by using multiple colors.
See also: dev_set_colored
This is an easy way to display multiple regions or XLDs. Each region is displayed in a different color, where the number of different colors is specified in the submenu. You can choose between 3, 6 and
12 colors. If all regions are still displayed with one color, you have to use the operator connection beforehand. You can check this also with the operator count_obj
. The default setting is to use 12 colors.
5.2.4.8
Color
Synopsis: Display regions, XLDs, and text in a specific color.
See also: dev_set_color
This item allows you to choose a color for displaying segmentation results (regions and XLDs), text created with write_string
, and general line drawings (e.g., 3D plots, contour lines, and bar charts).
The number of colors that are available in the submenu depends on the graphics display (i.e., the number of bits used for displaying). After selecting a color, the previously displayed region or XLD object will be redisplayed with this color if the menu entry Apply Immediately is checked.
The default color is red.
5.2.4.9
Draw
Synopsis: Draw type of regions.
See also: dev_set_draw
Here, you can select a visualization mode to display regions. It can either be filled (menu entry fill) or outlined (menu entry margin). If set to margin, the line thickness of the displayed regions is specified using the menu item Line Width.
5.2.4.10
Line Width
Synopsis: Line width used for the display of lines in active graphics window.
See also: dev_set_line_width
Here, you determine the line width for painting XLDs, borders of regions, or other types of lines. You can select between a wide range of widths using the submenu.
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5.2.4.11
Shape
Synopsis: Specify representation shape for regions.
See also: dev_set_shape
Here, you specify the representation shape for regions. You can display not only the region’s original shape but also its enclosing rectangle or its enclosing circle.
5.2.4.12
Lut
Synopsis: Specify look-up table for gray value mapping.
See also: dev_set_lut
This menu item activates different look-up tables, which can be used to display gray value images and color images in different intensities and colors. In the case of a true color display the image has to be redisplayed due to the missing support of a look-up table in the graphics hardware. For color images only the gray look-up tables can be used, which change each channel (separately) with the same table.
5.2.4.13
Paint
Synopsis: Specify image visualization.
See also: dev_set_paint
This menu item defines the mode to display gray value images. For more information see the menu item
Set Parameters... below.
5.2.4.14
Position Precision
Synopsis: Select the precision of subpixel mouse positions.
By default, mouse positions are displayed as integers (precision 0), where the upper left image pixel is displayed as 0, 0. Increasing the precision results in mouse positions being reported as subpixel-precise positions. Please note that when subpixel mouse positions are enabled, the position 0.0, 0.0 refers to the center of the upper left pixel, i.e, the upper left edge of the image is displayed as -0.5, -0.5.
5.2.4 Menu Visualization
5.2.4.15
Apply Immediately
Synopsis: Update behavior of visualization changes in active graphics window.
If this menu entry is checked, any changes to the visualization settings are applied immediately to the active graphics window. Otherwise, the changes are deferred until the next object is displayed in the active graphics window.
5.2.4.16
Update Window
Synopsis: Specify the output behavior of the active graphics window.
If this menu entry is checked, every object (image, region, or XLD) is displayed in the active graphics window during program execution. Otherwise, the active graphics window is not updated.
5.2.4.17
Reset Parameters
Synopsis: Reset the visualization parameters of the active graphics window to the default settings.
Here, the display parameters of the active graphics window are set to their initial state (as defined in the preferences, see page
62 ). The only exception is the size of the window. To clear the history of
previously displayed objects, use Clear Graphics Window. To set the size, use Window Size.
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5.2.4.18
Set Parameters...
Synopsis: Set visualization parameters of the active graphics window with interactive preview.
This menu entry opens the window Visualization Parameters which allows convenient access to the visualization settings of the active graphics window. Most of the settings are also available as individual menu entries in the menu Visualization, but some more advanced settings are only provided in this window. Furthermore, an interactive preview is provided, which visualizes the current settings.
• Select Graphics Window (only with multiple graphics windows)
Keep in mind that each graphics window keeps its own private set of visualization settings. When multiple graphics windows are opened in the current session, you can switch between the settings of the different graphics windows by selecting the corresponding window handle.
Figure 5.21: Visualization Parameters with multiple graphics windows.
• Update
This check box corresponds to the setting of Menu Visualization . Apply Immediately. If it is checked, every change of a parameter will immediately lead to a redisplay of the image, regions, or XLD in the graphics window. Otherwise, the parameters become active for the next display of an object (double-click on an icon or execution of an operator).
• Reset
Reset to the visualization settings defined in the
(page
• Use settings for new windows
Make the current settings also the default settings for new graphics windows.
5.2.4 Menu Visualization
2 Pen settings
Here, the display modes for regions and XLDs are specified. You can select the color (single or multiple), the drawing mode (filled or outlined), the line width, and the shape of the regions.
You can select up to 12 colors by clicking the appropriate check box. They are used to emphasize the connectivity of different regions in the graphics window. If you choose a single color presentation you may specify this color by selecting it in the list box.
With the parameter Shape (default is original), you may specify the presentation shape for regions.
You can display not only the region’s original shape but also its enclosing rectangle or its enclosing circle, etc.
The line width of the presented regions, XLDs, or lines is specified with help of the menu item Line
Width.
For regions the draw mode can be specified: Either it might be filled (item fill) or outlined (item margin).
These settings are also completely available from the corresponding menu entries in the menu
Visualization. A description of the functionality is provided there. The preview shows the current settings, which is helpful if the active graphics window does not contain any regions or XLDs.
• “Draw”, see also page
• “Colored”, see also page
• “Color”, see also page
• “Shape”, see also page
• “Line Width”, see also page
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2 LUT settings
Using LUT you are able to load different look-up tables for visualization. With the help of a false color presentation you often get a better impression of the gray values of an image. In the case of a true color display, the image has to be redisplayed due to the missing support of a look-up table in the graphics hardware. For color images only the gray look-up tables can be used, which change each channel (separately) with the same table.
See the description of the menu entry “Lut” on page
Figure 5.22: Visualization Parameters: LUT settings.
5.2.4 Menu Visualization
2 Paint settings
Here, you can select between several graphical image presentations. In the default mode the image is displayed unmodified. In the other modes the gray values of the image are taken as height information:
The greater the gray value, the higher the resulting image point. See
for an illustration of the different modes. Further information can be found at the description of the operators dev_set_paint and set_paint
. If you have chosen a presentation mode, the window displays all possible parameters you may modify.
• default
Display the image unmodified.
• row/column
Display the height information of a single horizontal/vertical image line. The gray values are scaled by the specified factor. The corresponding row/column can be selected by clicking into the graphics window or by entering the exact value.
• contourline
Display height lines. The gray value difference of the lines is defined by the parameter Step.
• 3d_plot_lines / _hidden_lines / _point
Display as a 3D plot using lines, computed hidden lines, or points.
• 3d_plot
Display a 3D plot using OpenGL which can interactively be modified in the graphics window. This mode can also be enabled from the tool bar of the graphics window. See page
default row 128, scale 20 column 128, scale 20 contourline, step 15
87
3d_plot_lines 3d_plot_hidden_lines 3d_plot_point
Figure 5.23: Comparison of the different paint settings.
3d_plot
88 Graphical User Interface
2 Zoom settings
See also: dev_set_part
As opposed to the mouse-based zoom functionality that is available in the tool bar of the graphics window, the tab card Zoom is parameterized. You can specify the bounding box of the visible area of an image, or set the center position.
Figure 5.24: Visualization Parameters: Zoom settings.
This tab card specifies which part of an image, region, XLD, or other graphic item is going to be displayed. The four text fields of Set part specify the coordinate system. Upper Left Corner defines the pixel which will be displayed at the upper left corner of the window. Lower Right Corner defines the pixel which will be displayed at the lower right side of the window.
Below the coordinates of the rectangle, you can specify its center.
The buttons Zoom Out and Zoom In activate a zooming with factor 0.5 or 2, respectively.
To get the image’s full view back on your graphics window, you simply click the button Reset.
The button Aspect adjusts the parameters so that the aspect ratio of the image is maintained.
5.2.4 Menu Visualization
5.2.4.19
Zoom Window
Synopsis: Open zoom window for image details and pixel inspection.
The zoom window is described in section “Zoom Window” on page
5.2.4.20
New Zoom Window
Synopsis: Open additional zoom window.
See section “Zoom Window” on page
5.2.4.21
Gray Histogram
Synopsis: Display gray value histogram of active graphics window.
Selecting this entry opens a sophisticated tool for the inspection of gray value histograms, which can also be used to select thresholds interactively and to set the range of displayed gray values dynamically.
It is described in section “Gray Histogram Window” on page
5.2.4.22
Feature Histogram
Synopsis: Interactive inspection of feature histograms.
This menu item opens a sophisticated tool for the inspection of feature histograms. It is described in section “Feature Histogram Window” on page
5.2.4.23
Feature Inspection
Synopsis: Inspection of shape and gray value features of individual regions.
This window provides a tool for the convenient inspection of shape and gray value features of individual regions. It is described in section “Feature Inspection Window” on page
5.2.4.24
Save Window ...
Synopsis: Save the contents of the active graphics window to an image file.
See also: dump_window
The graphics window is saved ‘as is’ (including displayed regions and XLDs). A file dialog pops up.
Select the destination directory, enter a file name, and select the output format (TIFF, BMP, JPEG, PNG, or PostScript). Afterwards, click Save to actually save the image file, or Cancel to abort.
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5.2.5
Menu Procedures
The menu Procedures contains all functionality that is needed to create, modify, copy, or delete HDevelop procedures. To save procedures, refer to the Menu File menu (page
5.2.5.1
Create New Procedure
Synopsis: Create a new internal or external procedure.
Selecting this item opens the
(page
113 ) window. The procedure interface
dialog and the mechanism of creating procedures are described in section “Creating and Editing Procedures” on page
5.2.5.2
Duplicate...
Synopsis: Copy a procedure under a different name.
Selecting this menu item opens a dialog with which it is possible to copy existing procedures. The dialog is displayed in
. The combo box Source contains all local procedures in the current program
and all external procedures. In the Target text field the name of the copied procedure can be entered.
Clicking the OK button creates a copy of the source procedure, Cancel dismisses the dialog. The copy retains the status (local or external) of the source procedure. The copy of an external procedure is placed in the same directory as the source procedure.
Figure 5.25: Duplicate Procedure.
Duplicating external procedures that are protected with a password (see “Protected External Procedures” on page
123 ) is also possible. The associated password is also used for the duplicated procedure.
5.2.5.3
Edit Interface
Synopsis: Edit procedure interface.
This menu item opens the procedure interface window and displays the interface of the current procedure
(or the first procedure from the list, if “main” is the current procedure). The menu item has the same effect as the button in the
(page
The interface of external procedures that are protected with a password can only be edited after the corresponding password has been entered (see section “Protected External Procedures” on page
5.2.5 Menu Procedures
5.2.5.4
Delete Current
Synopsis: Delete the current procedure.
If the current procedure is a local procedure, it is deleted from the program and the main procedure becomes the current procedure. All calls to the local procedure in the current program are marked as invalid code. This item is disabled if the current procedure is the main procedure, or if it is an external procedure.
5.2.5.5
Delete All Unused Local
Synopsis: Delete all local procedures that are not used in the current program.
All local procedures that cannot be reached by any procedure call from the main procedure are deleted from the program. If the current procedure is among the deleted procedures, the main procedure becomes the current procedure.
5.2.5.6
Insert Used As Local
Synopsis: Insert all used external procedures into the current program as local procedures.
The external procedures used in the current program are copied as local procedures. The external procedure files are left untouched.
5.2.5.7
Insert All As Local
Synopsis: Insert all external procedures into the current program as local procedures.
All external procedures are copied to the current program as local procedures, regardless if they are used or not. The external procedure files are left untouched.
With this menu item, you can change all of your procedures to become local. If your program contains protected external procedures, HDevelop issues a warning and inserts only the procedures that are not locked. Individual procedures can be made local (or external) via the check box Local in the procedures interface (see section “Procedure Interface Dialog” on page
113 ). For changing the edit status of an
external procedure see section “Protected External Procedures” on page
5.2.5.8
Make All External
Synopsis: Convert all local procedures into external procedures.
The formerly local procedures are now stored as external procedures in a selectable directory of the list of external procedure directories (see section “External Procedures -> Directories” on page
If no directories are configured, you can select a target directory from a dialog. HDevelop will add the selected target directory to the list if you tell it to. Otherwise, the operation will be canceled. For changing the edit status of an external procedure see section “Protected External Procedures” on page
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5.2.5.9
External Procedure Settings...
Synopsis: Configure settings for external procedures.
When you select this menu item, the window Preferences...
. External Procedures ->
Directories appears. With it, you can define one or more directories where external procedures are stored and searched for. Inside the defined directories, also the contained subdirectories are scanned.
Therefore, it is recommended to select directories with a restricted depth in order to speed up the search process. If you change the list of directories, the list of all available external procedures is updated.
See also section “External Procedures -> Directories” on page
5.2.5.10
Edit Procedure
Synopsis: Select a procedure for editing in the program window.
This submenu lists all procedures in submenus grouped by chapter and section title (see section “Procedure Interface Dialog” on page
113 ). Procedures without a chapter title are listed directly in the menu
Edit Procedure. If you click on a procedure name, it will become the current procedure in the program window. You can also select procedures in the combo box of the
(page
5.2.6
Menu Operators
Synopsis: Select HALCON operators and procedures.
This menu item comprises all HALCON and HDevelop operators including the HDevelop control constructs. Furthermore, procedures can be selected from a submenu at the bottom of this menu.
The following descriptions provide an overview of the operators specific to HDevelop programs. For detailed information about all operators it is highly recommended to read the corresponding sections of the reference manual. To get there quickly, select an operator from the menu, and click the button Help in the operator window.
5.2.6.1
Control
Synopsis: Select control flow operators.
Here, you may select control structures for the program. This involves the execution of a program segment (henceforth named body) depending on a test ( if
, ifelse
, and elseif
) and the repetition of a program segment ( for
, while
, and repeat
) with controlled loop execution ( break
, continue
).
Exception handling is implemented with try
, catch
, and endtry along with throw for user-defined exceptions. Furthermore, you may stop the program’s execution at any position ( stop
) or terminate
HDevelop ( exit
). The operators assign and insert do not influence the execution, but serve to specify values for control data (assignment). The operator comment is used to add a comment, that means any sequence of characters, to the program. The operator return terminates the current procedure call and
5.2.6 Menu Operators returns to the calling procedure (see section “Creating and Editing Procedures” on page
for more information about HDevelop procedures).
Selecting a menu item displays the corresponding control construct in the operator window, where you can set the necessary parameters. After specifying all parameters you may transfer the construct into your program. A direct execution for loops and conditions is not possible, in contrast to other HDevelop and HALCON operators, because you have to specify the loop’s and condition’s body first to obtain useful semantics. If necessary, you may execute the program after the input with Step Over or Run.
The IC is positioned after the construct head to ensure the input of the construct’s body occurs in the correct place. This body is indented to make the nesting level of the control constructs visible, and thus to help you in understanding the program structure. The semantics for loops and conditions are shown in section “Control Flow Operators” on page
Assignment
The operator assign serves as an assignment operator for control variables (numbers and strings). Analogously to “normal” operators the input is made in the operator window by specifying both “parameters”
Input and Result (i.e., right and left side of the assignment). An instruction in C, e.g., x = y + z; is declared inside the operator window as assign(y + z,x) and displayed in the program window by x := y + z
The operator insert implements the assignment of a single value (tuple of length 1) at a specified index position of a tuple. Thus, an array assignment (here in C syntax) a[i] = v; is entered as insert(a,v,i,a) in the operator window, and is displayed as a[i] := v
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in the HDevelop program window.
Program termination
The operators stop and exit are used to terminate the program. More precisely, stop interrupts an execution and exit terminates HDevelop. Having interrupted the execution you may continue the program by pressing Step Over or Run. This is useful, e.g., in demo programs to install defined positions for program interruption. Under UNIX, you can use exit in combination with a startup file and the command line switch -run. Thus, HDevelop will not only load and run your application automatically, but also terminate when reaching exit
.
Comments
The operator comment allows to add a line of text to the program. This text has no effect on the execution of the program. A comment may contain any sequence of characters.
5.2.6.2
Develop
Synopsis: Select operators specific to HDevelop.
This menu contains several operators that help to adapt the user interface. These operators offer the same functionality that you have using mouse interaction otherwise. They are used to configure the environment from within a program. Using these operators, the program performs actions similar to the setting of a color in the parameter window, opening a window in the menu bar, or iconifying the program window with the help of the window manager.
All operators in this menu start with the prefix dev_. It has been introduced to have a distinction to the underlying basic HALCON operators (e.g., dev_set_color and set_color
).
The effects of each operator are described as follows: dev_open_window
, dev_close_window
, dev_clear_window
The operators dev_open_window and dev_close_window are used to open and to close a graphics window, respectively. During opening, the parameterization allows you to specify the window’s size and position. The operator dev_clear_window clears the active window’s content and its history. This corresponds to the usage of the button Clear in the graphics window. Please note that dev_open_window and dev_close_window are not exported to Visual Basic, Visual Basic .NET, and C# because here one HWindowXCtrl is used.
dev_set_window_extents
With this operator, you can set the size and position of the active HDevelop graphics window.
dev_set_window
This operator activates the graphics window containing the given ID. This ID is an output parameter of dev_open_window
. After the execution, the output is redirected to this window. This operator is not needed for exported code in C++ or C, because here every window operation uses the ID as a parameter. The operator has no effect for exported code in Visual Basic,
Visual Basic .NET, and C#.
dev_set_color
, dev_set_colored dev_set_color has the same effects as the menu item Menu
Visualization . Color (page
dev_set_colored is equal to the menu item Menu
Visualization . Colored (page
5.2.6 Menu Operators dev_set_draw
This operator has the same effects as the menu item Menu Visualization . Draw
(page
dev_set_line_width
For an explanation see the menu item Menu Visualization . Line Width
(page
dev_set_lut
For an explanation see the menu item Menu Visualization . Lut (page
dev_set_paint
For an explanation see the menu item Menu Visualization . Paint (page
you want to specify all possible parameters of a given paint mode, you have to specify them as a tuple, analogously to the HALCON operator set_paint
.
dev_set_shape
For an explanation see the menu item Menu Visualization . Shape (page
dev_set_part
This operator adjusts the coordinate system for image, region, XLD and other graphic output. This is done by specifying the upper left and the lower right corner coordinates. This specified part is shown in the entire graphics window. If the width or height of the specified rectangle has a negative value (e.g., Row1 > Row2), the result is equivalent to the menu Menu
Visualization . Reset Parameters: the zoom mode is switched off, i.e., the most recently displayed image fills the whole graphics window. This feature of dev_set_part is not supported for exported C, C++, Visual Basic, Visual Basic .NET, and C# code.
dev_display
Iconic variables are displayed in the active graphics window by this operator. It is reasonable to do this when the automatic output is suppressed (see dev_update_window below and
Menu Edit . Preferences... . Runtime Settings -> Runtime Settings (page
dev_clear_obj
This operator deletes the iconic object stored in the HDevelop variable that is passed as the input parameter. In the variable window, the object is displayed as undefined (with a ? as its icon).
dev_inspect_ctrl
This operator opens an inspection window displaying the values of the variable passed to the operator. To inspect multiple variables at once, you can pass a tuple of variable names. In most cases a list dialog is opened, which shows all values of the variable (see also section “Inspecting and Editing Variables” on page
134 ). In the case of an image acquisition
device handle, a description of this image acquisition device is opened. In addition, this dialog allows online grabbing of images (see page
133 ). This operator is not supported for exported
code.
dev_close_inspect_ctrl
This is the opposite operator to dev_inspect_ctrl
, and closes the inspect window. This operator is not supported for exported code.
dev_map_par
, dev_unmap_par
These operators open and close the parameter dialog, which can also be opened using the menu Menu Visualization . Set Parameters.... This operator is not supported for exported code.
dev_map_var
, dev_unmap_var
These operators iconify the variable window ( dev_unmap_var
), and retransform the iconified window to the normal visualization size, respectively ( dev_map_var
).
This means that the variable window always remains visible on the display in one of the two ways of visualization. These operators can be executed with the help of the window manager. These operators are not supported for exported code.
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dev_map_prog
, dev_unmap_prog
Analogously to dev_map_var and dev_unmap_var
, these operators iconify or deiconify the program window. These operators are not supported for exported code.
dev_update_window
, dev_update_var
, dev_update_time
, dev_update_pc
Using these operators, you may configure the output at runtime. It corresponds to the settings in menu Menu Edit .
Preferences... . Runtime Settings -> Runtime Settings (page
not supported for exported code.
dev_set_check
This operator is equivalent to set_check of the HALCON library. It is used to handle runtime errors caused by HALCON operators that are executed inside HDevelop. The parameter value ’give_error’, which is the default, leads to a stop of the program together with an error dialog if a value not equal to H_MSG_TRUE is returned. Using the value ’~give_error’, errors or other messages are ignored and the program can continue. This mode is useful in connection with operators like get_mposition
, file_exists
, read_image
, or test_region_point
, which can return H_MSG_FAIL.
dev_error_var
This operator specifies a variable that contains the return value (error code) of an operator after execution. This value can be used to continue, depending on the given value.
dev_error_var is normally used in connection with dev_set_check
. Note that, as the procedure concept in HDevelop only allows for local variables, the variable set by dev_error_var will only be valid in calls to the relevant procedure. Furthermore, every corresponding procedure call will have an own instance of the variable, i.e. the variable might have different values in different procedure calls. For an example how to use dev_error_var in connection with dev_set_check see %HALCONROOT%\examples\hdevelop\Graphics\Mouse\get_mposition.dev.
Please note that operations concerning graphics windows and their corresponding operators have additional functionality in comparison to HALCON operators with corresponding names (without dev_): graphics windows in HDevelop are based on HALCON windows (see open_window in the HALCON reference manual), but in fact, they have an enhanced functionality (e.g., history of displayed objects, interactive modification of size, and control buttons). This is also true for operators that modify visualization parameters ( dev_set_color
, dev_set_draw
, etc.). For example, the new visualization parameter is registered in the parameter window when the operator has been executed. You can easily check this by opening the dialog Menu Visualization . Set Parameters... . Pen and apply the operator dev_set_color
. Here you will see the change of the visualization parameters in the dialog box. You have to be aware of this difference if you export dev_* to C, C++, Visual Basic, Visual Basic .NET, and
C# code.
In contrast to the parameter dialog for changing display parameters like color, the corresponding operators (like dev_set_color
) do not change the contents of the graphics window (i.e., they don’t cause a redisplay). They are used to prepare the parameters for the next display action.
5.2.6.3
Classification, File, Filter, ...
Synopsis: Select HALCON operators.
In the these menu entries, you can find all HALCON operators, arranged in chapters and sections. This set of image analysis operators forms the most important part of HALCON: the HALCON library. HAL-
5.2.6 Menu Operators
CON operators implement the different image analysis tasks such as preprocessing, filtering, or measurement.
You may look for a detailed description of each operator in the HALCON reference manual. Operators in the menus Control and Develop are special operators of HDevelop. Thus, you will not find them in the reference manuals for HALCON/C, HALCON/C++, or HALCON/COM.
The menu has a cascade structure, according to the chapter structure of the HALCON reference manual.
As this menu is built up dynamically when HDevelop starts, it might take some time until it is available.
During the build-up time the menu is “grayed out”. Selecting a chapter of the menu opens a pulldown menu with the corresponding sections or operators, respectively.
This operator hierarchy is especially useful for novices because it offers all operators sorted by thematic aspects. This might be interesting for an experienced user, too, if he wants to compare, e.g., different smoothing filters, because they reside in the same subchapter. To get additional information, a short description of an operator (while activating its name in the menu) is displayed in the status bar.
Note, that some operators are visible in the menus but should not be used, e.g., open_window
(in Menu
Operators . Graphics . Window) or reset_obj_db
(in Menu Operators . System . Database). If you select one of these operators, a warning text is displayed in the operator window. This warning will usually refer to a legal substitute. In the case of most of these operators, you should use the corresponding
Develop operator (e.g., dev_open_window instead of open_window
) within HDevelop.
5.2.6.4
Procedures
Synopsis: Select procedures.
This menu lists all internal and external procedures in submenus grouped by chapter and section. If no sectioning information is associated with a procedure, it appears directly in the submenu. Selecting a procedure inserts it into the operator window for editing.
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5.2.7
Menu Suggestions
Synopsis: Let HDevelop suggest operators based on the current operator.
This menu shows you another possibility how to select HALCON operators. But here they are proposed to you in a different manner. It is assumed that you have already selected an operator in a previous step.
Depending on this operator, five different suggestions are offered.
Suggestions are separated into groups as described below.
5.2.7.1
Predecessors
Many operators require a reasonable or necessary predecessor operator. For example, before computing junction points in a skeleton ( junctions_skeleton
), you have to compute this skeleton itself
( skeleton
). To obtain a threshold image you usually use a lowpass filter before executing a dynamic threshold ( dyn_threshold
). Using the watershed algorithms ( watersheds
), it is reasonable to apply a smoothing filter on an image first, because this reduces runtime considerably.
5.2.7.2
Successors
In many cases the task results in a “natural” sequence of operators. Thus, as a rule you use a thresholding after executing an edge filter or you execute a region processing (e.g., morphological operators) after a segmentation. To facilitate a reasonable processing, all the possible operators are offered in this menu item.
5.2.7.3
Alternatives
Since HALCON includes a large library, this menu item suggests alternative operators. Thus, you may, for example, replace mean_image with operators such as gauss_image
, sigma_image
, or smooth_image
.
5.2.7.4
See also
Contrary to Alternatives, operators are offered here which have some connection to the current operator. Thus, the median filter ( median_image
) is not a direct alternative to the mean filter ( mean_image
).
Similarly, the regiongrowing operator ( regiongrowing
) is no alternative for a thresholding. In any case, they offer a different approach to solve a task. References might consist of pure informative nature, too: the operator gen_lowpass
, which is used to create a lowpass filter in the frequency domain, is a reasonable reference to a Gaussian filter.
5.2.7.5
Keywords...
This menu item gives access to HALCON operators through keywords which are associated with each operator. The tab card Keywords of the online help window is opened. It is described in section
“Keywords” on page
5.2.8 Menu Assistants
5.2.8
Menu Assistants
This menu assembles assistants for specific machine vision tasks. The general concept of the assistants is described in the chapter “HDevelop Assistants” on page
The following assistants are available:
• Image Acquisition Assistant
• Calibration Assistant
• Matching Assistant
5.2.9
Menu Window
This menu offers support to manage the sub-windows of the main window, i.e., the program, operator, variable, graphics window(s), and possibly other dialogs. At the bottom of the menu all open windows are listed. Clicking an entry here brings the corresponding window to the front.
5.2.9.1
Open Graphics Window
Synopsis: Open an additional graphics window.
See also: dev_open_window
, and section “Open Graphics Window...” on page
If no graphics window is open, double-clicking an iconic variable will also open a new graphics window.
5.2.9.2
Open Program Listing
Synopsis: Open the program window.
See also: dev_map_prog
This menu item is grayed out if the program window is already open.
5.2.9.3
Open Variable Window
Synopsis: Open the variable window.
See also: dev_map_var
This menu item is grayed out if the variable window is already open.
5.2.9.4
Open Operator Window
Synopsis: Open the operator window.
This menu item is grayed out if the operator window is already open. If the full text editor is not enabled, you can also open the operator window by double-clicking a line in the program window.
99
100 Graphical User Interface
Figure 5.26: Tiled window layout of HDevelop.
5.2.9.5
Organize Windows
Synopsis: Clean up window area of main window.
When selecting this item, the main window is split into four areas: by default, all graphics windows are cascaded to fit the upper left quarter, the operator window fits the upper right quarter, the variable window fits the lower left quarter, and the program window fits the lower right quarter. The positioning can be adjusted in the preferences (see page
65 ). All other windows that are currently open are cascaded
at the center of the main window. In this arrangement, the four most important windows are placed in a non-overlapping fashion to provide maximum accessibility. It is therefore the default layout of
HDevelop.
If the full text editor is enabled and the operator window is closed, the program window will be stretched to occupy the configured position of the operator window as well.
The tiled layout is displayed in
5.2.9.6
Cascade Windows
Synopsis: Arrange windows in a cascade.
5.2.9 Menu Window
101
Figure 5.27: Cascaded window layout of HDevelop.
By selecting this item, HDevelop arranges the currently open windows in a cascade. The cascaded window layout is displayed in
5.2.9.7
SDI / MDI
Synopsis: Switch between multiple-document interface (the default) and single-document interface.
The different modes are explained in section “Main Window” on page
102 Graphical User Interface
5.2.10
Menu Help
Here, you may query information about HALCON itself and all HALCON and HDevelop operators.
5.2.10.1
Help
Synopsis: Open the online help window.
Shortcut: <F1>
The help window provides access to the documentation of HDevelop and HALCON. In particular, the complete HALCON Reference Manual is available with extensive documentation of each operator. Another possibility of requesting information about the current operator is pressing the button Help inside the operator window (see section “Operator Window” on page
The help window is described in section “Help Window” on page
5.2.10.2
HALCON Reference
Synopsis: Display the HALCON Reference Manual in the online help window.
5.2.10.3
HDevelop Reference
Synopsis: Display the HDevelop Reference chapter in the online help window.
5.2.10.4
HDevelop Language
Synopsis: Display the HDevelop Language chapter in the online help window.
5.2.10.5
Search Documentation
Synopsis: Open the online help window and show the search tab to enter search queries.
The online help provides an integrated search engine. You can enter search queries there and search the
HALCON documentation suite.
The search syntax is described in section “Help Window” on page
5.2.10.6
HALCON News (WWW)
Synopsis: Visit the HALCON home page.
This menu item lets you check for the latest news about HALCON on MVTec’s WWW server, e.g., whether new extension packages, image acquisition interfaces, or HALCON versions are available.
5.2.10 Menu Help
103
5.2.10.7
About
Synopsis: Display HDevelop version and licensing host IDs.
This menu item delivers information about the current HALCON and HDevelop version. Furthermore, it lists host IDs detected by the license manager (see the Installation Guide for more information).
104 Graphical User Interface
5.3
Tool Bar
You use most icons in this tool bar to accelerate accessing important HDevelop features. These are features which you are performing many times while working with HDevelop. Hence, there are buttons to handle your HDevelop programs and to edit them. The most important buttons are used to start and to stop a program (or parts of a program).
New program <(Ctrl+N>) (see page
Open program <(Ctrl+O>) (see page
Browse the supplied example program database <(Ctrl+E>) (see page
Save program or selected external procedure <(Ctrl+S>) (see page
Save all modifications in the program and external procedures <(Ctrl+Alt+S>) (see page
Export the program to another programming language (see page
Print (parts of) the current program <(Ctrl+P>) (see page
Cut highlighted program lines to internal buffer and system clipboard <(Ctrl+X>) (see page
Copy highlighted program lines to internal buffer and system clipboard <(Ctrl+C>) (see page
Delete highlighted program lines <(Del>) (see page
Paste program lines from internal buffer <(Ctrl+V>) (see page
Undo last editing action <(Ctrl+Z>) (see page
Redo last editing action <(Ctrl+Y>) (see page
Activate highlighted program lines <(F3>) (see page
Deactivate highlighted program lines <(F4>) (see page
Find/replace text in the current program <(Ctrl+F>) (see page
Run program from PC <(F5>) (see page
Step over next program line <(F6>) (see page
Step into procedure call <(F7>) (see page
Step out of procedure <(F8>) (see page
Stop program execution <(F9>) (see page
Reset program execution <(F2>) (see page
Reset current procedure execution <(Shift+F2>) (see page
Abort current procedure execution <(Shift+F8>) (see page
Display visualization settings (see page
Open zoom window (see page
Open gray histogram window (see page
Open feature histogram window (see page
Open feature inspection window (see page
Open help window <(F1>) (see page
5.4 Program Window
5.4
Program Window
The program window (see
) is divided into three areas:
• The main part of the program window contains the program code of the current HDevelop procedure. See section
• The column at the left side displays line numbers. It also contains the PC, the IC, and optionally, one or more break points. See section “Program Counter, Insert Cursor, and Break Points” on page
• At the top, the displayed procedure can be selected from the drop-down list. The arrow buttons provide convenient access to previously displayed procedures. If the current procedure is the main procedure, and you select another procedure from the drop-down list, the left arrow button takes you back to the main procedure. When you get there, the right arrow button moves forward, and displays the previously selected procedure again.
Using the rightmost tool bar button of the program window, the interface of the current procedure and its documentation can be edited, i.e., the number of parameters as well as their names and types, can be modified. See section “Creating and Editing Procedures” on page
for a detailed description. The remaining tool bar buttons affect the editing behavior.
Program Window Tool Bar
Move backwards in the history of displayed procedures.
Move forward in the history of displayed procedures.
Toggle editing mode (off : dialog-based editor, on: full text editor).
Toggle behavior of <Return> key (on: current program line is entered and executed, off : current line is entered).
Toggle advanced autocompletion on/off (full text editor only).
Edit interface and documentation of current procedure.
105
5.4.1
Editing Programs
HDevelop provides two complementary editing modes. First, there is the classical dialog-based editing mode. In this mode, program lines are edited in the operator window. It is the default method used in
HDevelop. Furthermore, there is a full text editing mode with advanced autocompletion. When it is enabled, the program code can be modified directly in the program window.
The editing mode can be switched in the toolbar of the program window (see Program Window Tool
Bar). You can also set the editing mode in the preferences (see the option Editor Settings in the
User Interface -> Program Listing on page
The two different editing modes are explained in the following sections.
106 Graphical User Interface
browse history current procedure edit interface advanced autocompletion execute on <Return> editing mode
PC
IC
BP
Figure 5.28: Program window.
5.4.1.1
Dialog-based Editor
In this mode, the program window is used to visualize program lines, but not to modify them. You cannot change the program body by modifying the text directly. Editing the program in HDevelop is done in the operator window (see section “Operator Window” on page
125 ). The main reason for this principle
is the clear separation of the parameters and the advantage that it facilitates providing sophisticated help.
Thus, many input errors can be avoided.
Every line starts with an operator or procedure name, which is indented, if necessary, to highlight the nesting level created by control structures.
After the operator or procedure name the parameters are displayed in parentheses. Parameters are separated by commas.
To edit a line of a program, you double-click it with the left mouse button. In case of conditions and loops the operator line with the parameters has to be selected. For example, you have to double-click for in a for...endfor loop, but until in a repeat...until loop. You may edit only one operator or procedure call at a time.
After double-clicking a program line, note the following:
5.4.1 Editing Programs 107
double−click edit parameters try parameters open online help submit edited program line
Figure 5.29: Editing a program line in the dialog-based editor.
• The program line is highlighted in a slanted font. This serves as a reminder that you are altering an existing program line instead of adding a new one.
• The operator or procedure call of the program line is displayed in the operator window and can be edited there.
• The window title of the operator window clearly indicates that you are editing an existing program line . It also displays the procedure name and the line number.
• Clicking OK or Replace in the operator window will replace the original program line. This is even the case if the corresponding program line is no longer in view, e.g., if a different procedure is selected in the program window.
If the program line is deleted before the changes are committed in the operator window, the edited line will be inserted as a new program line at the IC. If you are in doubt about the current status, check the window title of the operator window.
illustrates the editing process.
Copy, Paste, Delete
Besides editing the parameters of a single operator or procedure call, single and multiple lines can be deleted, cut, or pasted in one step using simple mouse functions. To use this feature, you select one or more lines in the program window using the mouse:
• You select one line by clicking on it. Previously selected lines will then become deselected.
• To select more than one line, press the <Ctrl> key while clicking on the each additional line.
108 Graphical User Interface
• The <Shift> key is used to select a sequence of lines using one mouse click: All lines between the most recent selection and the new one will become select.
After the selection of lines, the edit function can be activated by either using the menu Menu Edit, or the tool bar (see section “Tool Bar” on page
104 ), or via the context menu of the program window (see
page
5.4.1.2
Full Text Editor
The full text editor enables free text editing. You can click in the program window to place the cursor, and type ahead. You can select portions of the text with the mouse and have the selection replaced with what you type afterwards. This makes small changes to parameter values much faster than using the dialog-based editor.
Special input formats
The following assignments are equivalent. Both variants can be used in the full text editor, but the first variant is more readable:
FileName :=
'clip' assign(
'clip', FileName)
Individual tuple elements can be set in the following way. Both variants are equivalent, but the first variant is more readable:
Line[12] :=
'text' insert(Line,
'text', 1, Line)
Note that for loops always have to be entered in the following format: for Index := 1 to 10 by 1
...
endfor
Line continuation
Unlike the dialog-based editor, operator calls may span several lines for readability. This is indicated by entering the continuation character, i.e., a backslash character as the last character of the line.
For example, you can enter disp_arrow (WindowID, \
Row[i], \
Column[i], \
Row[i]-Length*sin(Phi[i]), \
Column[i]+Length*cos(Phi[i]), \
4)
5.4.1 Editing Programs 109
instead of disp_arrow (WindowID, Row[i], Column[i], Row[i]-Length*sin(Phi[i]), Column[i]+...
If you switch back to the dialog-based editor, continued lines will be displayed as single lines again.
Visually, the breaks seem to have disappeared. Actually, the formatting of the full text editor is preserved.
Thus, if you switch back to the full text editor mode, the formatting is restored in the program window.
Auto Indenting
The indent of new lines is adjusted automatically. Usually, the indent of the previous line is maintained.
If a line is continued inside the parentheses of an operator call, the new line is indented up to the opening parenthesis. If the previous line opens a control structure (e.g., if or while
), the indent is increased by the indent size. The indent size is specified in the preferences (see
(page
defaults to four spaces. If a control structure is closed (e.g., by entering endif or endwhile
), the indent of the current line is decreased by the indent size.
Advanced Autocompletion
The full text editor provides advanced autocompletion to support you in entering programs quickly and correctly without restricting your typing in any way. Autocompletion is enabled by default. It can be toggled on or off from the tool bar of the program window (see “Program Window Tool Bar” on page
When you start typing a new line, HDevelop will suggest a list of matching operator names:
Note that the line is highlighted as invalid (red in the default color scheme) because it is still incomplete.
The list is updated immediately as you continue typing:
Press <Tab> to complete to the longest common string. In this example, only one operator name remains in the list. Thus, it is fully completed, including the opening parenthesis of the operator call:
Once the cursor moves inside the parentheses, the suggestion list changes from operator mode to parameter mode. Furthermore, the signature of the selected operator is displayed, and the parameter corresponding to the cursor position is highlighted in bold.
110 Graphical User Interface
The first entry in this list is a suggestion that completes the full operator call up to the closing parentheses.
Again, typing ahead updates the list of suggestions accordingly. The remaining entries are suggestions for the first parameter of the operator call.
At this point, press <Tab> to select the first suggestion, or press <Up> or <Down> to step through the list entries, and press <Tab> or <Return> to select the highlighted entry. Then, enter a comma or press <Tab> again to get suggestions for the second parameter:
Note the browse button in the suggestion list. It opens up a
(page
file name parameter.
In this example, we want to load the image clip, so none of the suggestions fits. Just type the file name in single quotes (’clip’) and press <Tab> to complete the parameter list. The closing parenthesis is inserted automatically:
Special Keyboard Shortcuts in the Full Text Editor
General:
<F1>
<Tab>
<Shift>+<Tab>
<Shift>+<Return>
<Ctrl>+<Return>
<Ctrl>+<F> open the reference documentation of the operator or procedure call of the current line cursor at the beginning of line
: adjust indentation of current line selected text: indent corresponding code lines one level selected text : outdent corresponding code lines one level reverse action of <Return> key (see Program
Window Tool Bar) execute current line (same as clicking Apply in operator window, see section “Control Buttons” on page
open find/replace dialog with selected text
(section “Find/Replace...” on page
5.4.2 Program Counter, Insert Cursor, and Break Points 111
Advanced autocompletion:
<Escape>
<Ctrl>+<Space>
<Up>
<Down>
<Tab> hide suggestion list re-display suggestion list based on cursor position or selection highlight previous entry in suggestion list highlight next entry in suggestion list operator suggestions: complete to highlighted suggestion or to longest common string from suggestion list parameter suggestions: complete to highlighted suggestion or first suggestion if no suggestion is highlighted
5.4.2
Program Counter, Insert Cursor, and Break Points
The column to the left of the displayed program body contains the PC, represented as a green arrow pointing to a program line, the IC (a black triangle between two program lines) and optionally one or more break points (BP–a red STOP sign).
The program counter resides in the line of the next operator or procedure call to execute. The IC indicates the position to insert a new program line. A break point shows the program line on which the program is stopped.
You may position or activate these three labels by clicking in the left column of the program window.
That column itself is divided into three areas: Depending on the horizontal position of the mouse cursor, all three label types are available. The actual type is indicated through a change of the mouse cursor.
At the leftmost position, break points can be placed. In the middle position, the PC can be placed. And finally, in the rightmost position, the IC can be placed. HDevelop assists you by displaying the icon that would be inserted. If this seems confusing, you can force a specific label by holding down the following keys regardless of the horizontal position:
• Hold <Shift> to place the IC.
• Hold <Ctrl> to place or delete a BP.
• Hold <Shift>+<Ctrl> to place the PC.
Context Menu
By clicking into the program window with the right mouse button you can open a context menu, which contains shortcuts to some of the actions of the menus Menu Edit, e.g., copy and paste lines, and Menu
Execute, e.g., activate and deactivate lines or set and clear break points. Please note that these actions behave slightly differently than their counterparts in the main menus: When called via the main menus, the actions are performed only on the selected part of the program; if nothing is selected, no action is performed. In contrast, when an action is called via the context menu and no line is selected in the program, the action is performed for the line onto which you clicked with the right mouse button.
Note that any actions that modify the position of the PC will cause the call stack to pop all procedure calls until the current procedure call remains on top. This is relevant in case the current procedure call is
112 Graphical User Interface
not the top-most procedure call and is necessary to secure the consistency of the call stack. Modification of the PC can happen as well directly as described above or indirectly by, e.g., inserting a program line above the PC in the current procedure body.
The following entries of the context menu are not available elsewhere:
Run Until Here Execute the lines from the PC to the line under the mouse cursor.
Help If the line under the mouse cursor contains an operator call, the corresponding page is opened in the online help window. This is a shortcut to double-clicking the program line and clicking Help in the operator window.
Show Procedure If the line under the mouse cursor contains a procedure call, the corresponding procedure becomes the current procedure, i.e., it is displayed for editing.
Show Caller This menu item lists all the places in the current program where the currently displayed procedure is called. Clicking on an entry takes you to the corresponding program line.
Auto Indent If the full text editor is enabled, the indenting level of all selected program lines is indented in the same way as in the dialog-based editor, i.e., nested program blocks are indented by the amount of spaces set in the preferences.
5.4.3
Creating and Editing Procedures
HDevelop always displays one procedure, the current procedure, at a time. The combo box on top of the program window displays the name of the current procedure. You can select another procedure from this box. The first element of the list is the main procedure, followed by the local procedures of the current program, followed by the available external procedures. The procedure groups are sorted alphabetically.
When selected from the list, a procedure becomes the current procedure and the corresponding procedure call becomes the current procedure call. If the selected procedure has multiple calls on the stack, the last of the procedure calls is displayed.
If the procedure is locked, a password button is displayed instead of the procedure body. See
for an illustration. In order to access the code, the correct password has to be entered (see also section
“Protected External Procedures” on page
Figure 5.30: Display of a locked procedure in the program window.
5.4.3 Creating and Editing Procedures 113
iconic
{ input output control
{ input output add new parameter
Figure 5.31: Creating a new procedure.
5.4.3.1
Procedure Interface Dialog
The interface of the current procedure can be viewed and modified in a separate window, the procedure interface dialog. To open this dialog, click the button at the top of the program window. This button performs the same action as the menu item Menu Procedures . Edit Interface.
The procedure interface dialog enables you to create new and edit existing procedures. Using the upper buttons of this dialog, you can select the data associated with the current procedure: The button
Interface provides access to the procedure name, its type and its parameters. The remaining buttons provide access to the general documentation of the current procedure (General Documentation) and the documentation of its parameters (Parameter Documentation).
The documentation of the procedure may be entered in multiple languages. The language used for displaying the procedure documentation in the online help depends on the language set in the preferences of HDevelop.
To edit the procedure documentation in a specific language, select the corresponding entry from the drop-down list Language.
You can step through the individual tab cards of the dialog using the arrow buttons at the bottom of the dialog.
OK Activating the button OK at the bottom of the dialog either creates a new procedure or commits the changes made in the procedure interface, depending on whether the interface dialog was invoked in order to create a new procedure or to modify an existing procedure. In the latter case not only
114 Graphical User Interface
the interface itself might be changed but also the procedure’s program body and variable lists, as new variables might have been added or existing variables might have been removed or renamed.
If you change the interface of an external procedure, be aware of the fact that other programs containing it do not update the procedure calls. When loading these programs, the procedure calls are disabled. If the changes were applied to a procedure that is called from inside a protected external procedure, that procedure call is not even updated in the current program.
Cancel This button dismisses the dialog. Any changes to the interface or the documentation of the edited procedure are lost (with the exception of the editing status, see section “Protected External
Procedures” on page
Apply Applies the changes in the dialog (just like pressing OK) without closing it.
Help Displays the online help of the current procedure.
5.4.3 Creating and Editing Procedures
2 Interface
Procedure Name This text field specifies the name of the procedure. If the dialog is opened in order to create a new procedure, it contains a text field for the procedure name to be entered. If you edit an existing procedure, the name of the procedure is displayed in the combo box Procedure Name on top of the dialog. You can edit the interface of another procedure by selecting it from the combo box.
Type This check box determines whether the procedure is a local or external procedure. Local procedures are saved within the HDevelop program while external procedures are saved as stand-alone files. External procedures can be reused in other HDevelop programs.
Password External procedures can be protected by a password. Initially, external procedures are not protected, i.e., they can be viewed and modified by all users. How to protect passwords is discussed in section “Protected External Procedures” on page
123 ). Local procedures cannot be protected.
Adapt program If you are editing an existing procedure interface, this check box becomes available.
If it is checked, all calls to the procedure in the current program are checked for consistency and updated if necessary. Note that if new parameters are added to an existing procedure interface, the corresponding procedure calls are modified by adding new variables as input parameters, which most likely will not be initialized at the time of the procedure call.
Directory (external procedures only) For external procedures a storage path must be specified. When storing the external procedure for the first time, this path is preset to the first path in the list of external procedure locations as specified in the dialog Menu Procedures . External Procedure
Settings... (see page
92 ). You can select any of the configured external procedure paths from
the combo box. If you are editing an existing external procedure, the corresponding path is displayed but cannot be altered. Thus, once created external procedures can only be relocated in the file system.
You can also specify a new target directory by clicking the browse button next to the combo box.
If the selected directory is not in the list of external procedure locations, HDevelop will suggest to add it to the list when the changes to the dialog are committed. If the addition is canceled, the new procedure will not be available unless you add the corresponding directory manually.
If the specified directory is a subdirectory of one of the preconfigured locations, it will not be added to the list. This is because subdirectories are automatically searched in HDevelop.
Parameters
The next part of the dialog is used for the procedure interface parameters. As mentioned earlier, HDevelop procedure interfaces have the same structure as HALCON operator interfaces, that is, they may contain parameters of the four categories iconic input, iconic output, control input, and control output in this order. The procedure interface dialog contains four separate areas that offer the necessary functionality for manipulating parameters. These areas correspond to above parameter classes and are independent of each other. Every area is marked with an icon that describes the parameter class (see
on page
113 ). It contains a button for inserting new parameters, which are always appended at the end of
the parameter list. The latter is displayed by an array of text fields containing the parameter names.
115
116 Graphical User Interface
Reset If you are creating a new procedure, clicking this button removes all entered parameters. If you are editing an existing procedure, the original interface is restored, i.e., any changes to the parameters are undone.
Remove Using this button you can remove single parameters from the list. Before clicking this button, focus the corresponding parameter by clicking its text field.
Move Up, Move Down Using these buttons you can alter the order of the parameters. Select a parameter by clicking its text field and use the buttons to change its position.
2 General Documentation
5.4.3 Creating and Editing Procedures 117
Figure 5.32: Editing the general documentation of a procedure.
Basics
Procedures can be grouped by Library and Chapters (chapter and section).
Library This is the top level element of the content hierarchy in the procedure online help. It could be used to apply a vendor-specific tag to a group of procedures. The external procedures supplied with HALCON use the library tag “MVTec Standard Procedures”.
Chapters The text fields next to Chapters can be used to specify chapter and section, so that your procedures can be grouped thematically in the list at the bottom of the menus Menu Procedures and Menu Operators.
Note that the logical structure created by the chapter and section information does not correspond to the automatically created directory structure. At least for the external procedures, you can create the corresponding directory structure afterwards, outside of HDevelop. The recognition of the procedures in HDevelop is still ensured, as all subdirectories of the external procedure paths are scanned as well. When editing already existing external procedures, the changed procedures are stored in the paths they were originally found in.
118 Graphical User Interface
Short Description Enter a short description. Usually, this should be a single sentence that describes the purpose of the procedure. It appears in the overview sections of the online help of the procedures. Additionally, the short description is displayed in HDevelop’s status bar when the procedure is selected from the menu.
Detailed Description Enter a detailed description of the procedure. Paragraphs are introduced with a blank line.
Example
This section of the documentation is intended for code examples. This could be a working program or some code fragments that illustrate the usage of the procedure.
Suggestions
The first field on this tab card allows to associate keywords with the procedure. Enter a comma-separated list of keywords into this field. The tab card Keywords of the online help may be used as a reference for keyword suggestions.
Furthermore, you can specify suggested successors, predecessors, and alternatives to the current procedure.
Enter comma-separated lists of operator or procedure names into the fields.
See Menu
Suggestions for the meaning of these fields.
Advanced
The text boxes in this tab card are for advanced usage only. It is recommended, to search the online reference manual for usage examples.
Attention Notes about special observances when using the procedure.
Complexity Notes about intricate details about the procedure usage.
Warning Usually used to indicate obsolete or deprecated procedures that are kept for backward compatibility. The warning text should indicate the recommended alternative.
If the procedure is selected in the operator window, the warning text will be displayed as a reminder.
References Bibliographic references with recommended reading about certain aspects of the procedure.
2 Parameter Documentation
This section of the dialog provides tab cards for all parameters of the current procedure. The documentation consists of a fine-grained specification of the parameters, and a short description. The specification fields depend on the parameter type (iconic or control parameter), and on the selected semantics. In the following, the most common fields of both iconic and control parameters are listed.
Please refer to the Extension Package Programmer’s Manual (Chapter 2.3) for additional information about the documentation fields (especially, the semantic types).
Iconic Parameter Documentation
Field
Semantics
Pixel Types
Multi Channel
Multi Value
Description
5.4.3 Creating and Editing Procedures 119
Meaning
Specifies the data class of the parameter.
Only available for Semantics image. Lists the accepted pixel types. The buttons Select All and None toggle the selection of all parameters.
Only available if Semantics = image.
False : Only the first channel of the image is processed,
True : Only a multi-channel image is accepted,
Optional : Images with an arbitrary number of channels are accepted.
False : Only a single object (no object tuple) is accepted,
True : Only object tuples are accepted,
Optional : A single object as well as an object tuple is accepted.
Short description of the iconic parameter.
Figure 5.33: Editing the iconic parameter documentation of a procedure.
120 Graphical User Interface
Control Parameter Documentation
Field
Semantics
Type List
Default Type
Mixed Types
Default Value
Values
Value Min
Value Max
Multi Value
Description
Meaning
Specifies the data class of the parameter. For some semantic types, additional subtypes may be selected.
Specifies the accepted data types.
Specifies the default data type.
False : All values of a tuple have the same type,
True : Values of different types can be mixed in one tuple.
The entered value is suggested as the default value by HDevelop.
Comma-separated list of suggested values.
Check Exclusively to restrict the selection to the specified values.
Minimum value for numeric control data.
Check Enabled to enforce this setting.
Maximum value for numeric control data.
Check Enabled to enforce this setting.
False
: The parameter accepts only a single value,
True : The parameter always expects a tuple of values,
Optional : Single values as well as tuple values are accepted.
Short description of the control parameter.
Figure 5.34: Editing the control parameter documentation of a procedure.
5.4.3 Creating and Editing Procedures 121
Figure 5.35: Creating a procedure from selected lines.
5.4.3.2
Creating Procedures
New procedures are created by clicking the entry Menu Procedures . Create New Procedure. The program lines marked in the program window are copied and inserted in the program body of the new procedure. This is illustrated in
. If the last selected program line is not a
return operator, a return call is added at the end of the procedure body. If no lines are selected in the program window,
122 Graphical User Interface
the newly created procedure body initially contains only the return operator.
By default, a local procedure is created. If you want to create an external procedure instead, you have to disable the check box Local and optionally specify chapter and subchapter. Additionally, you can select the path the procedure is stored in, which by default is the first path specified in the preferences (see section “External Procedures -> Directories” on page
66 ). The section “Protected External Pro-
cedures” on page
shows how to protect an external procedure by a password so that only authorized persons can view and modify it.
When creating a new procedure from selected program lines, HDevelop automatically determines suitable interface parameters for the procedure from the usage of the variables in the selected code. The combo box Selection Scheme determines the suggestion of the procedure parameters. The meaning of this selection is as follows:
Only In If the first use of a variable inside the selected lines is as an input variable, it will be suggested as an input parameter of the procedure.
Only Out If the last use of a variable inside the selected lines is as an output variable, it will be suggested as an output parameter of the procedure.
All In All input variables inside the selected lines are suggested as input parameters in the procedure.
All Out All output variables inside the selected lines are suggested as output parameters of the procedure.
The classification of variables in the selected program lines is performed separately for iconic and control variables.
If a variable is an input as well as an output variable, it is assigned to the first category, i.e., the corresponding procedure parameter becomes an input parameter.
If, according to the above rules, a variable name would be suggested as an input as well as an output parameter, it becomes an input parameter of the procedure. In addition, an output parameter with the variable name extended by "Out" is created.
As an illustration, the following program lines are selected for a new procedure: threshold (Image, Region, 128, 255) connection (Region, ConnectedRegions)
Then, based on the selection scheme All In All Out, the procedure body will read copy_obj (Region, RegionOut, 1, -1) threshold (Image, RegionOut, 128, 255) connection (RegionOut, ConnectedRegions)
If the option Replace selected program lines is checked, the selected program lines are replaced by an appropriate call of the new procedure. Otherwise, the lines are kept and no procedure call is added.
In any case, the selected program lines are copied to the body of the new procedure as stated above.
The newly defined procedure is now available for selection in the operator window. The variables that were used to determine the procedure interface parameters are now being offered as input parameters for the procedure call.
5.4.3 Creating and Editing Procedures 123
Figure 5.36: Entering a password to protect an external procedure.
5.4.3.3
Protected External Procedures
External procedures can be protected by a password. The bodies of protected external procedures can only be accessed if the correct password is supplied. Protected procedure can be used by all users but viewed and modified only by authorized persons who know the password. The edit status of a procedure can be changed via the
(page
113 ). To manage the edit status of multiple
external procedures at once, click Menu Procedures . External Procedure Settings... and select the tab card
(page
By default, new procedures are local procedures, which cannot be protected. To make them external, the check box Local has to be disabled. Now, the button Password becomes available.
Protecting a Procedure
If you want to protect a procedure with a password, do the following:
• Select the corresponding procedure in the program window.
• Click to edit the interface of the selected procedure.
• Make sure Local is unchecked. Only external procedures can be protected.
• Click the button Password to assign a password to the procedure.
Then, a separate window appears and the new password must be entered twice. See
for an example. If both times the same password is used, clicking OK assigns the password. Otherwise, an error message is raised and you have to repeat the password assignment. When a protected procedure is finally saved, it is stored in a binary format.
When you start HDevelop the next time, the protected procedure is locked, i.e., when trying to edit the procedure, e.g., by selecting it from the combo box in the program window, a corresponding message is displayed in the program window. See
for an example. Additionally, a password button is displayed in the program window. Upon entering the correct password, the procedure is temporarily unlocked and stays unlocked as long as you do not close HDevelop.
Changing the Edit Status of a Protected Procedure
To change the status of a protected procedure, you must first unlock it temporarily by entering the password. Then, you can use the
(page
113 ) to change the password or remove the
124 Graphical User Interface
Figure 5.37: A locked external procedure.
Figure 5.38: Changing the edit status of a protected procedure.
password to turn the protected external procedure into an unprotected external or even a local procedure.
Click the button Password to change the edit status.
The following options are available:
Lock You can lock the protected procedure so its body cannot be accessed in the current session without supplying the password again.
Remove Selecting this option removes the password. When the procedure is saved, it is no longer protected. For turning a protected external procedure into a local procedure (without a password) it is sufficient to activate the check box Local in the
(page
New password The password window appears and you assign the new password by the same process you used for the old one.
Cancel The operation is canceled without altering the status.
Warning
When working with protected procedures, be aware that the password cannot be reconstructed, so be very careful not to forget it and not to repeat a typing error when assigning it! Further, in some situations protected external procedures behave differently from common external or local procedures. In particular, as they cannot be viewed and modified by unauthorized users, they also cannot be copied, printed, or exported to any programming language (however, they can be duplicated using the menu entry Menu
5.5 Operator Window 125
Procedures . Duplicate...). Additionally, if a protected external procedure contains a call to another procedure for which the interface was changed, the procedure call is not adapted to the changes but is disabled for the current program.
5.5
Operator Window
This window is used to edit and display an operator or procedure call with all its parameters. Here you will obtain information about the number of the parameters of the operator or procedure, the parameter types, and parameter values. You can modify the parameter values according to your image processing tasks. For this you may use the values proposed by HDevelop or specify your own values.
The operator window consists of the following three parts:
• At the top you find the operator name field, with which you can select operators or procedures.
• The large area below the operator name field is called the parameter display; it is used to edit the parameters of an operator or procedure.
• The row of buttons at the bottom allows to control the parameter display.
5.5.1
Operator Name Field
The operator name field allows to select operators or procedures by entering (part of) their name. After pressing <Return> or pressing the button of the combo box, the system is looking for all operators or procedures that contain the entered name. The order of the listed result is as follows: Operators and procedures whose names begin with the given substring are listed first, followed by all operators and procedures that contain the substring elsewhere. Both parts of the list are sorted in alphabetical order.
If there is an unambiguous search result, the parameters are displayed immediately in the operator window. If there are several matching results, a combo box opens and displays all operators or procedures containing the specified substring. By clicking the left mouse button you select one operator and the combo box disappears. Now, the operator’s parameters are shown in the operator window.
The short description of the selected operator is displayed in the status bar. The operator name is displayed in the window title of the operator window.
5.5.2
Parameter Display
The parameter display is the main part of the operator window. If you have selected an operator or procedure call, HDevelop displays its interface, i.e., the name, value, and semantic type of each parameter.
• In the first column of the parameter display the parameter types are indicated by icons. Note that icons are not repeated if a parameter is of the same type as its predecessor. Hover the mouse cursor over the icons to get a tool tip with the short description of the parameter.
• In the second column of the operator window you find the parameter names.
126 Graphical User Interface
Figure 5.39: Selecting an operator after typing select_.
• The third column consists of the text fields, which contain variable names in case of iconic and control output parameters and expressions in case of control input parameters. If you want to change the suggestions offered by the system (variable names or default values), you may do so either manually or by pressing the arrow button connected with the respective text field. This opens a list containing a selection of already defined variables and other reasonable values from the operator knowledge base. By clicking the appropriate item, you set the text field and the list disappears.
For the operators open_framegrabber
, set_framegrabber_param
, and get_framegrabber_param
, the value list of certain parameters is dynamic: It depends on the selected image acquisition interface. An even more reasonable parameter suggestion is given if the corresponding handle is opened. If this dynamic behavior is undesired, it can be disabled in the preferences, see General Options -> Experienced User settings on page
This column may also contain action buttons for special semantic types, e.g., a button to browse the file system for the parameters that expect a file name.
• The fourth column indicates the parameter’s default semantic type and, optionally, its data type in parentheses.
Hover the mouse cursor over the second to fourth column to get a short description for the corresponding parameter as a tool tip.
Please refer to the following rules on how parameters obtain their values and how you may specify them:
Iconic input parameters Possible inputs for these parameters are iconic variables of the corresponding type. If there is no need to execute the operator or procedure call immediately, you may specify new variable names, i.e., names, that do not already exist in the variable window, but will be instantiated later by adding further operators or procedure calls to the program body. In any case,
5.5.2 Parameter Display 127
Figure 5.40: Specifying parameters for the operator select_shape.
you have to specify iconic parameters exclusively with variable names. It is not possible to use expressions.
Iconic output parameters These parameters contain default variables, which have the same names as the parameters themselves. If a variable with the same name as the output parameter is already instantiated, a number is added to the name to make it unique. Because the parameter names characterize the computed result very well, you may adopt these default names in many cases.
Besides this, you are free to choose arbitrary names either by yourself or by opening the list (see above). If you use a variable that already has a value, this value is overwritten with the new results.
It is possible to specify a variable both in an input and output position.
Control input parameters These parameters normally possess a default value. As an alternative, you may use the text field’s button to open a combo box and to select a suggested value. In addition, this combo box contains a list of variables that contain values of the required type. A restriction of proposed variables is especially used for parameters that contain data like file, image acquisition, or OCR handles.
Input control parameters may contain constants, variables, and expressions. Common types are integer numbers (integer), floating-point numbers (real), boolean values (true and false), and character strings (string).
You can also specify multiple values of these types at once by using tuples. This is an array of values, separated by commas and enclosed in square brackets. Furthermore, you may build up expressions with these values. You may use expressions in HDevelop similar to the use of expressions in C or in Pascal. You will find a detailed description in section “Expressions for Input
Control Parameters” on page
Control output parameters: These parameters are handled in the same way as iconic output parameters. Their defaults are named as their parameter names. Other possibilities to obtain a control
128 Graphical User Interface
output variable name are either using the combo box or specifying variable names manually. You cannot use any expressions for these parameters.
After discussing what can be input for different parameters, it is explained how this is done. Nevertheless, you have to keep in mind that you need to modify a parameter only if it contains no values or if you are not satisfied with the suggested default values.
Text input: Give the input focus to a parameter field by clicking into it. Now, you may input numbers, strings, expressions, or variables. There are some editing functions to help you doing input:
<Backspace> deletes the character to the left and <Delete> deletes the one to the right. You may also select a sequence of characters in the text field using the mouse or holding <Shift> and using the cursor keys. If there is a succeeding input, the marked region is going to be deleted first and afterwards the characters are going to be written in the text field. See page
for a summary of the keyboard mappings.
Combo box selection: Using this input method, you can obtain rapid settings of variables and constants.
To do so, you have to click the button on the text field’s right side. A combo box is opened, in which you may select an item. Thus, you are able to choose a certain variable or value without risking erroneous typing. Previous entries are deleted. Afterwards, the combo box is closed. If there are no variables or appropriate values, the combo box remains closed.
5.5.3
Control Buttons
Below the parameter display, you find five buttons that comprise the following functions:
Ok By clicking Ok you execute the operator or procedure call with the specified parameters. When doing so, the execution mode depends on the position of the PC: If the PC is placed above the insertion position, the system executes the program from the PC until the insertion position first. Then, the operator or procedure call that has been edited in the operator window is executed. The reason for this is that the parameter values that are used as input values for the currently edited operator or procedure call have to be calculated. If the PC is placed at or after the insertion position, only the currently edited operator or procedure call is executed.
The operator or procedure call is entered into the program window before it is executed. After the execution, the PC is positioned on the next executable program line after the edited operator or procedure call.
The computed output parameter values are displayed in the variable window. Iconic variables are shown in the current graphics window if you haven’t suppressed this option (compare section
“Runtime Settings -> Runtime Settings” on page
72 ). Afterwards, the operator window is
cleared. If you did not specify all parameters or if you used wrong values, an error dialog is raised and execution is canceled. In this case, the operator window remains open to allow appropriate changes.
Enter / Replace By clicking the button Enter, the currently edited operator or procedure call is transferred into the program window without being executed. When editing existing program lines
(through double-clicking in the program window, see page
106 ), the button label changes to
Replace. When clicked, the original program line is replaced.
5.6 Variable Window 129
Apply If you click Apply, the operator is executed with the specified parameters, but not entered into or changed in the program. This enables you to determine the optimum parameters rapidly since the operator dialog remains open, and hence you can change parameters quickly. Note that this functionality is not available for procedure calls, and thus the button is grayed out in this case.
Unlike the button Ok, only the single line you edit or enter is executed, no matter where the PC is located. Thus, you have to ensure that all the input variables contain meaningful values. By pressing Apply, the corresponding output variables are changed or created, if necessary, to allow you to inspect their values. If you decide not to enter the line into the program body, some unused variables may thus be created. You can easily remove them by selecting Menu File . Cleanup.
Cancel Clicking Cancel clears the contents of the operator window. Thus, there are neither changes in the program nor in any variables.
Help Clicking Help invokes the online help for the selected operator or procedure. For this the system activates the online help window (see Help Window).
5.6
Variable Window
There are two kinds of variables in HALCON, corresponding to the two parameter types of HALCON: iconic objects (images, regions, and XLDs) and control data (numbers, strings). The corresponding variables are called iconic and control variables. These variables may possess a value or may be undefined.
An undefined variable is created, for example, when loading a program or after inserting an operator with a new variable that is not executed immediately into a program. You may access these undefined variables only by writing to them. If you try to read such a variable, a runtime error occurs. If a variable obtains a value, the variable type is specified more precisely. A control variable that contains, for example, an integer is of type integer. This type might change to real or a tuple of integer after specifying new values for this variable. But it always remains a control variable. Similarly, this is the case for iconic variables, which may contain regions, images, or XLDs. You may assign new values to an iconic variable as often as you want to, but you cannot change its type so that it becomes a control variable.
In addition to classifying HDevelop variables by whether they are iconic or control variables, they can also be distinguished by whether they are interface parameters of the current procedure or local variables.
Generally, both kinds of variables are treated equally.
New variables are created in the operator dialog area during specification of operator or procedure call parameters. Here, every sequence of characters without single quotation marks is interpreted as a variable name. If this name did not exist before, the variable is created in the operator dialog area by pressing
Ok or Enter. The variable type is specified through the type of the parameter where it was used for the first time: Variables that correspond to an iconic object parameter create an iconic variable; variables for a control parameter create a control variable. Every time an operator or procedure call is executed, the results are stored in variables connected to its output parameters. This is achieved by first deleting the contents of the variable and then assigning the new value to it.
The variable window is similar to a watch window used in window-oriented debuggers. Inside this window you are able to keep track of variable values. Corresponding to the two variable types, there are two areas in the variable window. One for iconic data (above or left) and the other for control data
(below or right).
130 Graphical User Interface
Figure 5.41: Variable window with instantiated iconic and control variables.
All computed variables are displayed showing their iconic or control values (unless the automatic update has been switched off, see section “Runtime Settings -> Runtime Settings” on page
of a tuple result which is too long, the tuple presentation is shortened, indicated by three dots. In this case the full content of a variable can be displayed in an inspection window by double-clicking the value list. See also the following sections.
Switching Between Horizontal and Vertical Layout
You can toggle the orientation of the two parts of the variable window. To do this, double-click the dividing line between both parts. You can also drag that line to resize the parts.
Managing Variables
In large programs the variable window can become quite cluttered, which makes watching selected variables difficult. Therefore, you can customize the selection of displayed variables. At the bottom of the variable window, three tabs are available:
• All: All variables of the current procedure are displayed at once.
• Auto: The variables of the current and the previous operator call are displayed. This is useful when single-stepping through the program, because only the variables relevant to the current context are displayed.
• User: A user-defined selection of variables is displayed. Variables may be added and removed using the context menu of the variable window (see below). If the tab User is active, variables may be added from a list in the context menu. In the other two tabs variables are added by selecting them first and clicking Add to User Tab in the context menu.
5.6.1 Iconic Variables 131
Context Menu
In both parts of the variable window distinct context menus are available by right-clicking in the window.
The entries that are common in both parts are described here.
• Clear Variable: The selected variables are cleared and appear as undefined.
• Add to User Tab: The selected variables are added to the tab User.
• Sort by Name: The variables are sorted in alphabetical order.
• Sort by Occurrence: The variables appear in the same order as they are defined in the program.
• Update Variables: Toggle whether variables will be updated during program execution. This is the same setting as in the runtime preferences (see page
• Cleanup: Delete all unused variables (see page
Only applicable when the tab User is selected:
• Add Variable: This submenu contains a list of all variables that are currently not displayed in the tab User. Clicking a variable name adds the variable to the tab.
• Remove from User Tab: The selected variables are removed from the tab User.
5.6.1
Iconic Variables
The iconic variables are represented by icons, which contain an image, a region or an XLD, depending on the current value. The icons are created depending on the type of data according to the following rules:
• For images the icon contains a zoomed version of them, filling the icon completely. Due to the zooming onto the square shape of the icon, the aspect ratio of the small image might be wrong. If there is more than one image in the variable, only the first image is used for the icon. Similarly, for multi-channel images only the first channel is displayed. An exception is made for images with 3 channels: These are displayed as color icons (RGB).
The domain of the image is not reflected in the displayed icon. Information about the domain can be obtained from the tool tip which appears when the mouse cursor points to the icon. See
for an illustration.
• Regions are displayed by first calculating the smallest surrounding rectangle and then zooming it so that it fills the icon using a border of one pixel. In contrast to images, the aspect ratio is always correct. This can lead to black bars at the borders. The color used to draw the region is always white without further modifications (except zooming).
• XLD data is displayed using the coordinate system of the largest image used so far. The color used for XLD objects is white on black background.
Because of the different ways of displaying objects, you have to be aware that the coordinates cannot be compared. The variable name is positioned below each icon. They are displayed in the variable window in the order of occurrence or name from left to right. If there is not enough space, a scrollbar is created, which you can use to scroll the icons.
132 Graphical User Interface
Figure 5.42: Displaying information about an iconic variable with a reduced domain.
Displaying Iconic Variables
Double-clicking an icon with the left mouse button displays the data in the active graphics window. If you use images of different sizes in a program, the system uses the following output strategy for an automatic adaption of the zooming: Every window keeps track of the size of the most recently displayed image. If you display an image with a different size, the system modifies the graphics window coordinate system in a way that the image is visible completely in the graphics window. If a partial zooming has been activated before (see section “Graphics Window” on page
136 ), it is going to be suppressed.
Displaying Information about Iconic Variables
You can get information about an instantiated variable by placing the mouse pointer over the corresponding icon in the variable window. See also
for an illustration. The information depends on the contents of the corresponding variable:
• Images: The image type and size and the number of channels is displayed. If the iconic variable contains multiple images, the properties of the first image are reported.
• Regions: The area and the center of the region is displayed. If the iconic variable contains multiple regions, the properties of the first region are reported.
• XLDs: The number of contour points and the length is displayed. If the iconic variable contains multiple XLDs, the properties of the first XLD are reported.
Context Menu
Clicking on an icon with the right mouse button opens a context menu with several options. You can display the corresponding iconic variable in the active graphics window (with or without clearing the window first), and you can clear the iconic variable. If an iconic variable contains multiple items, you can also select a specific item from a submenu. Up to 15 items are listed in this menu. If an iconic variable contains more than 15 items, the remaining items can be accessed by clicking Select.... If you click Select... in this submenu, you can quickly browse the items of the iconic variable from a dialog. This also works for multi-channel images. See
for an example.
5.6.2 Control Variables 133
channel 1 channel 2 channel 3
Figure 5.43: Interactive channel selection from an RGB image.
Normally, regions, images, and XLDs are represented in variable icons. Besides this there are three exceptions, which are shown by special icons:
• Undefined variables are displayed as a question mark (?) icon. You may write to but not read them, because they do not have any value.
• Brackets ([]) are used if a variable is instantiated but does not contain an iconic object (empty tuple). This may be the case using operators like select_shape with “wrong” specified thresholds or using the operator gen_empty_obj
. Such a value might be reasonable if you want to collect iconic objects in a variable gradually in a loop using concat_obj
. Here, an empty tuple is used as starting value for the loop.
• A last exception is an empty region. This is one region that does not contain any pixels (points), i.e., the area (number of points) is 0. You must not confuse this case with the empty tuple, because there the area is not defined. The empty region is symbolized by an empty set icon (∅).
5.6.2
Control Variables
To the right of the variable name you find its values in the default representation (you have to keep in mind that a floating point number without significant fractional part is represented as an integer, e.g., 1.0
is represented as 1). If you specify more than one value for one variable (tuple), they are separated by commas and enclosed by brackets. If the number of values exceeds an upper limit, the output is clipped.
This is indicated by three dots at the end of the tuple. For undefined variables, their name and a ? are
134 Graphical User Interface
shown in the variable field. An empty tuple is represented by []. Both exceptions use the same symbols as the corresponding cases for the iconic variables.
Inspecting and Editing Variables
See also: dev_inspect_ctrl
Double-clicking a control variable opens a window that displays all its values in a tabular format. This is helpful if you have tuple variables with a large number of values that you want to inspect. Below the list, some statistical data may be displayed (minimum value, maximum value, sum of values, mean value, deviation, types, number of values, and the semantics if appropriate. You can select which statistical data is displayed by right-clicking on the statistics table and selecting the corresponding entries.
You can also select multiple control variables at once in the variable window by holding down the <Ctrl> key. To inspect these variables in a single inspection window, right click on the selected variables and select Inspect.
An example inspection window is displayed in
Control variables that reference a matrix are displayed in a tabular format as displayed in
Copying Values to the Clipboard
Within the variable window, the context menu offers an entry for copying the values of the selected variable to the system clipboard. If the variable window has the keyboard focus, <Ctrl-C> can be used as an alternative. Tuples with zero or more than one values are returned in tuple notation: [.., ..]. If several variables are selected, the tuples of the different variables are separated by a new line.
Figure 5.44: Control variable inspection.
5.6.2 Control Variables 135
Figure 5.45: Inspection of a matrix control variable.
Inspecting Image Acquisition Device Handles
For an image acquisition device handle, a dialog representing basic image acquisition device parameters is opened. Here you find the size, name, device, port, and other features of the image acquisition device.
The toggle button Online allows to grab images continuously and to display them in the active graphics window. Multiple online inspections from different image acquisition devices at the same time are also supported by opening additional graphics windows before clicking the corresponding button Online. If an error occurs during grabbing, it is displayed in the status bar of the dialog. The dialog is displayed in
grab images
Figure 5.46: Inspecting an image acquisition device handle.
136 Graphical User Interface
5.7
Graphics Window
This window displays iconic data. It has the following properties:
• The user may open several graphics windows.
• The active graphics window is shown by the lit bulb in the window’s tool bar.
• Pressing the clear button clears the graphics window content and the history of the window.
• You close a graphics window using the close button of the window frame.
shows an example graphics window which is displaying a gray value image of a tooth rim overlaid with region data. One of the displayed regions is selected (illustrated by the dashed border).
The variable name and index of the selected region is displayed in the title bar.
Figure 5.47: Graphics Window.
Every HDevelop graphics window has its own visualization parameters. Thus, modifying the parameters
(see section “Menu Visualization” on page
79 ) applies to the currently active graphics window only,
i.e., the parameter settings of all other open graphics windows remain unchanged. Additionally, the new parameter settings are used as the default settings in all graphics windows yet to be opened.
The origin of the graphics window is the upper left corner with the coordinates (0,0). The x values
(column) increase from left to right, the y values (row) increase from top to bottom. When the mouse cursor is placed inside a graphics window, the coordinates (row, column) and the gray value at that position are displayed in the status bar (see page
44 ). Sometimes, it is desired to display this information
close to the mouse cursor. This can be achieved by holding down the <Ctrl> key (note: this does not work when the zoom in and out tool is selected since pressing <Ctrl> inverts the corresponding zoom action).
shows the coordinate/gray value display.
Normally, the coordinate system of the graphics window corresponds to the most recently displayed image, which is automatically zoomed so that every pixel of the image is visible. The coordinate system can be changed interactively using the tool bar of the graphics window or the menu Menu Visualization
. Set Parameters... . Zoom (see section “Menu Visualization” on page
5.7 Graphics Window 137
Figure 5.48: Coordinate display in the graphics window.
dev_set_part
(see section “Develop” on page
94 ). Every time an image with another size is displayed,
the coordinate system will be adapted automatically.
Each window has a history that contains all
• objects and
• display parameters that have been displayed or changed since the most recent clearing or display of an image. This history is used for redrawing the contents of the window. The history is limited to a maximum number of 30
“redraw actions”, where one redraw action contains all objects of one displayed variable.
Other output like text or general graphics like disp_line or disp_circle or iconic data that is displayed using HALCON operators like disp_image or disp_region are not part of the history, and are not redrawn. Only the object classes image, region, and XLD that are displayed with the HDevelop operator dev_display or by double-clicking on an icon are part of the history.
You may change the size of the graphics window interactively by “gripping” the window border with the mouse. Then you can resize the window by dragging the mouse pointer. After this size modification the window content is redisplayed. Now, you see the same part of the window with changed zoom.
3D Plot Mode
Clicking activates an interactive 3D plot mode. It displays meaningful information for height field images, i.e., images that encode height information as gray values. The greater the gray value, the higher the corresponding image point.
shows a height field image and the corresponding 3D plot.
The 3D plot mode uses OpenGL and benefits from hardware acceleration.
Using the mouse you can alter the view of the 3D image (select mode must be active for this to work, click in the tool bar):
• Drag the image to rotate the view.
138 Graphical User Interface
a) b) c)
Figure 5.49: a) Default image display, b) 3D plot mode, c) Display settings.
• Hold <Shift> and drag the image up and down to zoom out and in, respectively. Alternatively, use the mouse wheel.
• Hold <Ctrl> and drag the image to translate the view.
There are four different rendering methods (texture, shaded, hidden_lines, and contour_lines) which can be selected from the drop-down menu in the tool bar. See set_paint for detailed information about the different methods. The display quality may be fine-tuned in the visualization parameters of the graphics window. Right-click into the graphics window, select Set Parameters..., and open the tab card Paint: "Mode"
• Mode sets the rendering mode just like the drop-down menu in the graphics window.
• Plot Quality allows to set the rendering quality in four steps. On systems without proper display hardware acceleration a lower quality should be selected to speed up the display.
• Step sets the level of detail. In general, the lower the step value, the higher the level of detail.
However, if the rendering mode is set to contour_lines, increasing the step value increases the level of detail.
• If Display Grid is enabled, the “floor” of the 3D plot is painted as a grid.
See also section “Paint settings” on page
for the other paint modes that may be selected in this window.
Special Keyboard Shortcuts in the Graphics Window
<Left, Right, Up, Down>
<Alt>+<Left, Right, Up, Down>
<Ctrl>+<Left, Right, Up, Down>
<Ctrl>+<Alt>+<Left, Right, Up, Down> move mouse cursor 1 pixel move mouse cursor 10 pixels pan image 1 pixel pan image 10 pixels
Graphics Window Tool Bar Icons
Clear the graphics window and its history.
5.7 Graphics Window 139
Figure 5.50: Magnifying glass.
Switch to select mode. In this mode, you can select regions or XLDs that are displayed in the graphics window. A selected item is highlighted with a dashed border. If multiple layers of region/XLD data are displayed in the graphics window, the first click selects the uppermost region/XLD under the mouse cursor. Each subsequent click at the same position selects the region/XLD below the currently selected item. The variable name of the selected item is displayed in the title bar of the graphics window for reference.
You can use the select mode to inspect gray value histograms and features of individual regions or
XLDs.
In the example image illustrated in
on page
136 , the displayed image of a tooth rim is
overlaid with region data. A single region is selected.
Combined move/zoom tool. Drag the displayed image with the left mouse button to alter the displayed portion. Use the mouse wheel to zoom in and out.
Magnifying glass. Click into the graphics window to magnify the area at the mouse cursor. See
for an illustration of this tool.
Zoom in. Click the small arrow next to the icon to switch to zoom out.
Zoom out. Click the small arrow next to the icon to switch to zoom in.
Set image size. Clicking this icon sets the image size to the shown value. The value can be selected from the menu attached to the small arrow. See section “Image Size” on page
for additional information.
Set window size. Clicking this icon sets the window size to the shown value. The value can be selected from the menu attached to the small arrow. See section “Window Size” on page
for additional information.
Toggle 3D plot mode.
140 Graphical User Interface
Active graphics window.
Non-active graphics window. Click the icon to activate the corresponding graphics window. Only one graphics window may be active any given time.
If you want to specify display parameters for a window, you may select the menu item Visualization in the menu bar. Here you can set the appropriate parameters by clicking the desired item (see section
“Menu Visualization” on page
79 ). The parameters you have set this way are used for the active
window. The effects of the new parameters will be applied directly to the last object of the window history and alter its parameters only.
5.8
Help Window
The help window provides access to the integrated online help of HDevelop. The window is split in two areas: On the left, navigational panels are available as tab cards. They are described below. On the right, the online help itself is displayed. Anyone familiar with a web browser will be able to navigate through the hypertext. The size of the two parts of the help window can be altered by dragging the dividing line.
With the help window you can easily browse the HALCON Reference Manual, the Procedure Reference
Manual, the HDevelop Reference Manual and the Programmer’s Manuals. Furthermore, the complete offline documentation of HALCON, which is available in PDF format, can be accessed from this window.
The help window also includes a full-text search engine to rummage both online and offline documentation.
Contents
This tab card presents the chapters and sections of the online documentation as a hierarchical tree. Click on a node of the tree to display the associated document.
Operators
This tab card lists all operators in alphabetical order. Click on an operator name to display the corresponding page from the Reference Manual. Enter any name into the text field Filter to show only operators matching that name.
Search
Enter a search query into the text field, and click Search to start a full-text search. Both online documentation (HTML) and offline documentation (PDF) are searched. The search result is displayed below the query. The rank (in percent) indicates how well each found document satisfies the query.
The query may consist of one or multiple words. HDevelop will find all documents that contain any of the specified words.
To search for a phrase, enclose it in double quotes:
"radiometric calibration"
5.8 Help Window 141
Figure 5.51: Help Window.
Boolean searches with and, or, and not can also be specified. To find all documents that say anything about filters except Gaussian filters, enter: filter not gauss
Keywords
This tab card gives access to HALCON operators and relevant sections of the documentation through keywords just like an index in a book. The list of keywords can be filtered by entering any word into the text field Filter. If you enter multiple words, only keywords matching all the words are displayed.
When you select keywords from the list, the related operator names and links to the corresponding parts of the documentation are displayed below the keywords. You can click on an operator name to read its documentation in the online help. If you click on a documentation link, the corresponding PDF is opened in the registered PDF viewer. Please note that the link text also includes the page number so you can find the desired information very quickly.
142 Graphical User Interface
Figure 5.52: Keywords and associated HALCON operators.
Bookmarks
This tab card lists all user-defined bookmarks. You can add the currently displayed document to the list by clicking the button Add. To remove a bookmark from the list, select it and click the button Delete.
Help Window Tool Bar Icons
Go back in the browse history.
Go forward in the browse history.
Go to the starting page of the HALCON Reference Manual.
Increase the font size of the help window.
Decrease the font size of the help window.
Add the currently displayed document to the
Open the operating system dependent printer selection dialog to print the currently displayed page.
5.9 Zoom Window 143
If the currently displayed document is the reference page of a HALCON operator, select this operator in the operator window.
Syntax The online pages of the HALCON Reference Manual are available for the language interfaces
HDevelop, C++, C, .NET, and COM. The displayed variant can be selected through this list box.
Find Enter a word or substring to find it in the currently displayed document. The first match is highlighted as you type. If no match is found, the text field blinks shortly. You can use the cursor keys
(down and up) to highlight the next match or the previous match, respectively. Alternatively, you can use the following two buttons.
Next Highlight the next match.
Prev Highlight the previous match.
Special Keyboard Shortcuts in the Help Window
<Alt>+<Left>
<Alt>+<Right>
<Alt>+<Home>
<Alt>+<Return>
<Ctrl>+<p>
<Ctrl>+<+>
<Ctrl>+<->
<Ctrl>+<d>
<Tab>
<Shift>+<Tab>
<Enter> go back in the browse history go forward in the browse history go to starting the page of the HALCON Reference Manual enter operator into operator window print current page increase font size decrease font size add current page to the bookmarks highlight next link highlight previous link jump to highlighted link
5.9
Zoom Window
Synopsis: Zoom window for image details and pixel inspection.
See also: Menu Visualization . Zoom Window
The zoom window enables the interactive inspection of image details. You can open up any number of zoom windows with different zoom levels (see Menu Visualization . New Zoom Window). The window also displays the gray values of each image channel at the mouse cursor position. Apart from this, the pixel type, the number of channels, and the current position of the mouse cursor are displayed.
The percental scale can be selected from the combo box. It is related to the original size of the image.
There are multiple methods to navigate the zoom window:
Check Follow Mouse and move the mouse pointer over the image to select the zoomed area. Click once to keep the currently displayed area in the zoom window, when the mouse cursor moves out of the image window. Or, uncheck Follow Mouse and click (or drag) inside the image to select the zoomed
144 Graphical User Interface
area. The red square in the center of the zoom window indicates the position of the mouse cursor. The corresponding coordinates are also displayed at the bottom of the window.
You can select a particular pixel by single-clicking on it with the left mouse button. The zooming tool stores this position internally, and will redisplay the thus selected part of the image object when you leave the graphics window. This enables you to have a meaningful display in the zooming tool whenever you want to do actions outside of the graphics window.
For finer control of the zoomed area, click inside the zoom window to give it the focus and use the cursor keys to move pixel-wise. Press and hold the Alt key and use the cursor keys to move ten pixels at a time.
Click inside the zoom window to move relative to the center position. For example, clicking ten pixels above the center will move the view up ten pixels.
The lower part of the window contains a gauge to display the gray value of the center pixel graphically.
The range goes from 0 (left) to 255 (right). Normally, the gray value of the first channel is displayed with a black bar. For images with multiple channels the gauge is split accordingly to show individual bars for each channel. Thus, for color images in RGB-space (three channels with red, green, and blue values) three colored bars are used. If the gray value is below 1, the gauge is light gray (background). If the value is above 255, the gauge is dark gray or colored for RGB images.
Above the gauge, the gray values are displayed as numbers. Up to five channels are displayed. If more than five channels are present, the remaining channel values are truncated.
Next to the gauge, the coordinates of the mouse position are displayed. Below these, the image size, pixel type, and the number of channels are shown.
The button next to the scale combo box enlarges the zoom window so that partially visible pixels at the border become fully visible.
Figure 5.53: Zoom.
5.10 Gray Histogram Window
5.10
Gray Histogram Window
Synopsis: Display gray value histogram of active graphics window.
See also: Menu Visualization . Gray Histogram
The gray histogram window is a sophisticated tool for the inspection of gray value histograms, which can also be used to select thresholds interactively and to set the range of displayed gray values dynamically.
When opening the tool, the histogram of the image shown in the currently active graphics window is displayed. When the tool is already open, the following means of sending new image data to the tool are available:
• Make another graphics window active or display another image in the active graphics window.
145
Figure 5.54: Gray Histogram.
146 Graphical User Interface
Whenever you do so, the histogram of this image is computed and drawn, and the tool records the graphics window from which the image was sent (the originating window).
• Whenever image data is displayed overlaid with region data in a graphics window (the graphics window does not need to be active for this), you can click into any of the segmented regions, and the histogram of the image within that region will be computed and shown. If you click into a part of the image that is not contained in any of the overlaid regions, the histogram of the entire image will be displayed.
• The same mechanism is used for regions that have gray value information, e.g., image objects created by reduce_domain or add_channels
. Here, the histogram of the image object you click into will be displayed.
Freeze Gray Histogram
Sometimes, it is desirable to suppress the updating of the histogram when new image data is available, e.g., if you want to select thresholds for a gradient image, but want to visualize the original image along with the segmentation (see below). In that case you can freeze the histogram by unchecking Update. The currently displayed histogram is preserved until Update is checked again in which case the histogram will be re-calculated from the active graphics window.
Gray Histogram Display
The main part of the tool is the area, in which the histogram of the image is displayed in blue. This area contains static parts and parts that can be interactively manipulated. The first static part is the horizontal coordinate axis, which displays the gray values in the image. For byte images, this range is always
0...255. For all other image types, e.g., real images, the horizontal axis runs from the minimum to the maximum gray value of the image, and the labeling of the axis is changed accordingly. To the left of the display, the vertical axis representing the frequency of the gray values is drawn. The final static parts of the display are three gray arrows. The two upward pointing arrows denote the maximum and minimum gray value of the image. The downward pointing arrow denotes the peak of the histogram, i.e., the gray value that occurs most frequently. This data is displayed in textual form within the Statistics area of the display. For int4, int8, or real images, the peak value is displayed as a value range in the Statistics.
That is, the range of input values is divided in quantization steps to obtain a meaningful histogram, and, as a consequence, the histogram’s “peak value” may actually represent a whole range of input values.
The dynamic parts of the histogram area are the two colored lines, which can be manipulated. The vertical green and red lines denote the minimum and maximum selected gray value of the histogram, respectively. The gray values on which the two vertical lines lie are displayed next to the lines in the same color.
Histogram Options
• Quantization: Display the histogram quantized. The bucket size can be specified with the slider or entered into the spinner box.
5.10 Gray Histogram Window 147
• Smoothing: Display the histogram smoothed. The smoothing factor can be specified with the slider or entered into the spinner box.
Horizontal/Vertical: The visible part of the histogram can be specified parametrically by entering the minimum and maximum values into the spinner boxes. These values are adapted when the visible area is set with the buttons next to the histogram.
Whenever new image data is evaluated in the gray histogram window, the adaptation of these values depends on the selected adaptation mode, which can be set independently for horizontal and vertical ranges:
• adaptive
In this mode, the upper and lower boundary of the displayed gray values will always be adapted when a new image is displayed. The maximum and minimum value for the threshold bars (green and red) are also fixed to the maximum gray value of the type of image currently displayed.
Note that if you are using 8-bit and 16-bit images in a mixed mode, the histogram will constantly be reset. Thus, it is not possible to display a 16-bit image, set thresholds, then display an 8-bit image and keep the threshold values of the 16-bit image.
• increasing
In this mode, only the upper boundary of the displayed gray values will be adapted and it will only increase, but never decrease. This for instance is useful when first inspecting 8-bit images, but then switching to 16-bit images. In this situation, the histogram will simply display the 16-bit gray value range after displaying the first 16-bit image.
In this mode, the minimum and maximum value of the threshold bars are not limited to the currently displayed image type. The reason is simple: This mode allows to inspect images of a different data type with the same threshold values. If the values were always limited, the histogram would
"forget" the values like in the adaptive mode.
• fixed
In this mode, the boundaries are not adapted automatically (but can be changed manually). This mode is also suitable for scenarios with images of mixed data types.
Like in the mode increasing, the minimum and maximum value of the threshold bars are not limited to the currently displayed image type.
Gray Histogram Tool Bar
Display linear histogram (the default).
Display logarithmic histogram.
Initially, the histogram is displayed at full vertical range, i.e., up to the peak value. The displayed part can be manipulated with the following buttons:
Zoom histogram display to a selected area. Click this button and drag an area inside the histogram to view that area.
Spread the histogram horizontally so that only the area between the lines is displayed.
148 Graphical User Interface
Display the full histogram.
Reset the display of the histogram vertically.
Reset the display of the histogram horizontally.
Force minimum histogram width. Do not adjust the width of the histogram when resizing the window.
5.10.1
Interactive Visual Operations
The selected range of gray values can be used for two major purposes: Thresholding (segmentation) and scaling the gray values.
threshold threshold + connection scale
The gray values between the green line and the red line can be visualized either in the originating or the active graphics window as specified in Output Destination in the Output area of the window.
The type of visualization is specified in the table below the histogram. Click the + button to add a new operation to the table. Click the - button to remove an operation from the table. The column Operation specifies the operation that is applied to a selected range of gray values (threshold or scale, see below).
To visualize a specific operation, click the corresponding icon next to the operation.
When a multi-channel image, e.g., a RGB color image, is sent to the tool, by default the histogram of the first channel is displayed. The column Channel lets you select the channel from which to compute the histogram.
The columns Min and Max correspond to the position of the green and the red line, respectively. Each operation may specify its own range of gray values.
add operation remove operation visualize operation
5.10.1 Interactive Visual Operations 149
5.10.1.1
Threshold Operation
The image from which the histogram was computed is segmented with a threshold operation with the selected minimum and maximum gray value.
With the three combo boxes Color, Draw, and Line Width in the Output section of the window you can specify how the segmentation results are displayed (see also Colored, Draw, and Line Width).
If you want to select threshold parameters for a single image, display the image in the active graphics window and open the histogram tool. For optimum visualization of the segmentation results, it is best to set the visualization color to a color different from black or white. Now, set Operation to Threshold and interactively drag the two vertical bars until you achieve the desired segmentation result. The parameters of the threshold operation can now be read off the two vertical lines.
If you want to select threshold parameters for an image that is derived from another image, but want to display the segmentation on the original image, e.g., if you want to select thresholds for a gradient image, two different possibilities exist. First, you can display the derived image, open the histogram tool, deselect Update, display the original image, and then select the appropriate thresholds. This way, only one window is needed for the visualization. For the second possibility you can display the derived image in one window, activate another window or open a new window, display the original image there, activate the first window again, open the histogram tool, activate the second window again, set Output
Destination to active window, and select your thresholds. Although in this case it is not necessary to deselect Update, it is advantageous to do so, because this prevents the histogram from being updated if you click into a graphics window accidentally.
Multiple Threshold Operations You can combine as many threshold operations as you like. If multiple operations are visualized at the same time, the display depends on the combo box below the table of operations: If none is selected, the results of the different threshold operations are displayed independently.
If union is selected, the results are combined to a single region. If intersection is selected, only the common pixels from all results are visualized.
Connected Regions
Clicking Connection displays the connected regions of the selected gray values in the style specified with Color, Draw, and Line Width.
This display mode is similar to a plain threshold operation. Additionally, it performs a connection operation. The separate regions can only be distinguished if Color is set to colored 3, colored 6, or colored 12.
Click the button Insert Code to generate HDevelop code that performs the currently visualized threshold operation(s) in your program. The code is inserted at the IC.
5.10.1.2
Scale Operation
The scale operation maps the gray values between the green line and the red line to the full range (usually
0...255). See also scale_image
.
The gray values of the image are scaled such that the gray value 0 of the scaled image corresponds to the selected minimum gray value and the gray value 255 to the selected maximum gray value. Again, the combo box Output Destination determines the graphics window, in which the result is displayed.
150 Graphical User Interface
This mode is useful to interactively set a “window” of gray values that should be displayed with a large dynamic range.
You can define as many scale operations as you like, but only one of them may be visualized in the graphics window at the same time.
Click the button Insert Code to generate HDevelop code that performs the currently visualized scale operation in your program. The code is inserted at the IC.
5.11 Feature Histogram Window
5.11
Feature Histogram Window
Synopsis: Interactive inspection of feature histograms.
See also: Menu Visualization . Feature Histogram
This window provides a sophisticated tool for the inspection of feature histograms. In contrast to the gray value histogram described in the previous section, this tool does not inspect individual pixels, but regions or XLDs; for these iconic objects, it displays the distribution of values of a selected feature, e.g., the area of an XLD or the mean gray value of the pixels within a region. The feature histogram can also be used to select suitable thresholds for the operators select_shape and select_shape_xld interactively. Similar to the gray histogram tool, the interactive selection can be translated into generated
HDevelop program code.
Upon opening, the tool displays the histogram of the area (default feature selection) of the regions or
XLDs that were displayed most recently in the currently active graphics window. You can select various features in the combo box Feature; Further information about region features can be found in section
“Feature Inspection Window” on page
See
for an illustration. First, all objects (regions) of a certain size (area) are selected.
Then, the selection is refined by adding further restrictions. In this example, the final selection should only include round objects, i.e., regions with a high roundness feature. The following code would be generated if you clicked the button "Insert Code" in this example: select_shape (Connection, SelectedRegions, [
'area','roundness'], 'and',
[2900,0.72], [3900,0.79462])
Most parts of the tool are built up similarly to the gray value histogram, which is described in detail in section “Gray Histogram Window” on page
(Menu Visualization . Gray Histogram). It is highly recommended to read that description beforehand; in the following, we concentrate on points specific to the feature histogram. An important point regards the “source” of the regions or XLDs: The feature histogram is calculated for the regions or XLDs that were displayed most recently in the graphics window. Thus, if you display an image, and there are no regions or XLDs, the histogram remains
“empty”. As soon as you display regions or XLDs on top of an image, the histogram is calculated. If you display regions or XLDs without an image, you can still calculate feature histograms, but only for shape features. Please keep in mind that only the most recently displayed regions or XLDs are the source of the histogram, not all objects currently displayed in the graphics window!
The histogram itself is displayed with the horizontal axis corresponding to the feature values and the vertical axis corresponding to the frequency of the values, i.e., to the number of regions or XLDs with a certain feature value.
When comparing feature histograms to gray value histograms, you will note a typical difference: Because in most cases the overall number of regions or XLDs is much smaller than the overall number of pixels, feature histograms often consist of individual lines, most of them having the height 1. Of course, this effect depends on the selected feature: For features with floating-point values, e.g., the orientation, the probability that two regions or XLDs have the same feature value is very small, in contrast to features with integer values, e.g., the number of holes.
151
152 Graphical User Interface
select objects of similar size AND restrict the selection to round objects
Figure 5.55: Combining different features selections.
5.12 Feature Inspection Window 153
You can influence the calculation of the histogram with the slider Quantization. The selected value is used to discretize the horizontal axis: Instead of determining the frequency of an “exact” feature value, regions with feature values falling within discrete intervals are summed. Graphically speaking, the horizontal axis is subdivided into “bins” with a width equal to the value selected with the slider
Quantization.
add feature remove feature visualize feature
As with the gray histogram operations, each selected feature has to be enabled to visualize the selection in the graphics window.
5.12
Feature Inspection Window
Synopsis: Inspection of shape and gray value features of individual regions.
See also: Menu Visualization . Feature Inspection
This window provides a tool for the convenient inspection of shape and gray value features of individual regions and XLDs. It can, for instance, be used to determine thresholds for operators that select regions based on these features, e.g., select_shape or select_gray
.
The strategy to determine the data from which to compute the features is very similar to that of the gray histogram inspection window (see section “Gray Histogram Window” on page
an image or region by double-clicking on it in the variable window or you can select a region or an image which is already displayed by single-clicking it. If you display or click into an image, the gray value features of the entire image will be calculated. If you click into a region that is not underlaid with an image, only the shape features of this region will be displayed. If you click into a region that is underlaid with an image or into a region that has gray value information (e.g., from reduce_domain or add_channels
), both the shape and gray value features of that region will be displayed. Finally, if you have overlaid an image with a region, but click into a part of the image that is outside the region, only the gray value features of the entire image will be calculated.
Use the “select” tool of the graphics window to select a region or XLD. The selected region or XLD is highlighted in the graphics window. The corresponding variable name and index are displayed in the title of the feature inspection window.
The gray value features of a multi-channel image are calculated from all channels independently.
The tree on the left side of the feature inspection window groups the features into several categories. At the top-most level, the following groups of features are distinguished:
• Region features: This group contains features that describe the selected region, e.g., area, center, and orientation.
• Gray value features: The feature values of this group are calculated from the gray values of the image under the selected region, e.g., minimum and maximum gray value, mean gray value, anisotropy and entropy.
154 Graphical User Interface
select selected region feature value of selected region visualization specified range
Figure 5.56: Inspection of selected features.
• XLD features: This group contains features that describe the selected XLD (e.g., its dimensions or shape properties).
You can select the features to be inspected by ticking the corresponding check boxes in the tree. The selected features are displayed on the right side of the window. For each feature the calculated value of the selected region or XLD is displayed (or the value for the entire image). The current value is also visualized as a gauge in a value range that can be set to the desired values. Simply select Show
Minimum/Maximum, which is available in the context menu of the right side of the window.
See
for an illustration of a clip inspection. The range for the area feature has been set to
[4000, 6200]. Individual clips can be inspected by selecting them in the graphics window.
Moving the mouse pointer over a feature value displays a tool tip. It shows the name and short description of the HALCON operator used for the calculation of that value. Using the context menu, you can insert the corresponding operator into the operator window.
5.13 Dialogs
5.13
Dialogs
5.13.1
File Selection Dialog
The file selection dialogs opened by actions such as Open Program..., Save, or Read Image are native windows of the operating system and thus their appearance and internal functionality is beyond
HDevelop’s control. Their basic functionality is to browse the file system, and to select one or multiple files (or in some cases: directories). Usually, they have two buttons: The one labeled Open or OK confirms the selection and thus performs the initial action (e.g., loading a file) while the other (labeled Cancel) aborts the initial action.
As an example, the dialog Menu File . Open Program... is explained.
155
Figure 5.57: Example of a file selection dialog under Windows.
In the top-most text field you may specify a directory which contains your HDevelop programs. A combo box at the right hand side helps you browsing your directories. To move one directory level up, you press the button on the right hand side of this text field. The next button creates a new folder to store HDevelop programs. By pressing the last button you can activate or deactivate the option to see more details about your HDevelop programs, i.e., the program size, the program type, the date when the most recent user update occurred, and file attributes.
The middle text area displays all available HDevelop files to choose from. By clicking the left mouse button on a file name you select it. Double-clicking a file name opens the file immediately and displays it in the
(page
Furthermore, you may specify the file name in the text field below the file list. The combo box for file type has no effect because only HDevelop programs with the extension .dev can be loaded. To open
156 Graphical User Interface
your specified file, you press the button Open. This action deletes an already loaded HDevelop program and all created variables. The same actions as with File . New Program are performed. Now you can see the main procedure body of your new program in the program window. The file name is displayed in the title bar of the main window. All its (uninstantiated) variables are shown in the variable window.
To indicate that they do not have any computed values, the system labels the iconic and control variables with a question mark. The program counter is placed on top of the program body and you are ready to execute the program. The visualization and options will be reset after loading (same as Menu File .
New Program, see page
You can cancel this task by pressing the corresponding button. By using one of the two buttons Open or
Cancel, the dialog window disappears.
5.13.2
Unsaved Changes
File operations that will delete the current program (such as loading a new program) trigger a security check. This security check prevents you from deleting the current program accidentally if the program has not been saved. A dialog box appears and asks whether you want to save the HDevelop program before its dismissal:
Figure 5.58: Confirmation dialog.
Save Save the current program under its current name and proceed. If no name has been specified yet, a file dialog pops up to enter the name.
Save As Save the current program under a different name and proceed.
Discard Discard unsaved changes and proceed.
Cancel Abort the current action.
HDevelop Assistants 157
Chapter 6
HDevelop Assistants
HDevelop contains assistants for specific machine vision tasks. Each assistant provides a user interface tailored to the requirements of its task. Using this interface, you can interactively set up and configure the assistant to solve a specific machine vision problem. Once the configuration is working satisfactorily, the assistant can be instructed to generate HDevelop code into the current program. You can also save an assistant’s configuration for later use.
The following assistants are available:
• Image Acquisition: Using this assistant you can generate code to acquire images from different sources (files, directories, image acquisition interfaces).
The assistant is described in section “Image Acquisition Assistant” on page
using this assistant is available in
on page
• Calibration: Using this assistant you can calibrate your camera and therefore gain information about parameters of the camera system and distortions in the image. Calibrating your system constitutes a preparation for your subsequent application as it provides the basis for you to measure with high precision in the world coordinate system.
The assistant is described in section “Calibration Assistant” on page
• Matching: Using this assistant you can generate code to perform shape-based matching in your
HDevelop program. You can load a reference image to train a model. Using a selection of test images containing the model you can tweak a set of parameters to find the model in all variations permitted by the application. Furthermore, the parameters can be optimized to increase the processing speed.
The assistant is described in section “Matching Assistant” on page
Common Features of all HDevelop Assistants
Some features are common to all HDevelop assistants. First of all, you can open multiple assistants.
Assistants of the same type are numbered consecutively, e.g., if you open two image acquisition assistants, they are labeled “Image Acquisition 01” and “Image Acquisition 02”, respectively. When you open a new assistant, a menu entry is added to the top of the menu Assistants, from which the
158 HDevelop Assistants
corresponding assistant can be restored if it has been closed. The current setup is lost and the menu entry disappears if the associated assistant is exited explicitly (see below). If you want to keep the setup for later sessions, you can always save it to a file.
Different assistants have different menus (usually corresponding to the available tab cards). These menus provide functionality specific to the assistant’s task. There are also some menu entries that are available in every assistant. They are described in the following.
File . Load Assistant Settings Using this entry, a previous configuration can be loaded from a file which has been generated using the menu entry Save Current Assistant Settings.
File . Save Current Assistant Settings You can save the configuration of an assistant to a file for later use. The default extension for these configuration files is .das.
File . Close Dialog The assistant is closed, but the current configuration is preserved. This menu entry performs the same function as the assistant’s close button. You can restore a closed assistant by clicking the numbered entry in the menu Assistants which is generated when a new assistant is opened.
File . Exit Assistant The assistant is quit. The resources used by the assistant are released. The link to the generated code is lost, i.e., it is not possible to restore the assistant unless the setup has been saved to a file. The menu entry in the menu Assistants is also removed.
Code Generation . Insert Code Insert HDevelop code based on the current settings of the assistant.
The code is inserted at the IC. As long as the associated assistant is not quit, you can change the settings and update the code accordingly.
Code Generation . Release Generated Code Lines The link to the generated code is cut off.
The code remains in the program, but can no longer be updated or removed from the (formerly) associated assistant. Nevertheless, you can generate new code with the current settings of the assistant.
Code Generation . Delete Generated Code Lines The generated code is deleted from the program. Please note that any manual changes to the generated lines are deleted as well.
Code Generation . Show Code Preview Generate a preview of the code based on the current setup of the assistant. If the program already contains generated code which is linked to the current assistant, the changed code lines can be compared side-by-side in the preview.
6.1
Image Acquisition Assistant
The image acquisition assistant is an easy-to-use front-end to the various image acquisition methods supported by HALCON. Firstly, it lets you read images from the file system (selected files or whole directories). More importantly, it supports acquiring images from image acquisition devices that are supported by HALCON’s image acquisition interfaces. When an image acquisition interface is selected, the corresponding device parameters, e.g., the image format can be set. After establishing a connection to the selected image acquisition interface, images can be grabbed and displayed in the active graphics window.
Using live images, the parameters supported by the selected interface can be explored interactively.
6.1.1 Tab Source
159
When a suitable setup is achieved, the settings of the assistant can be saved for later reuse. The assistant can also be instructed to generate HDevelop code that will connect to the selected image acquisition interface, set the specified parameters and grab images.
6.1.1
Tab Source
Synopsis: Select from where to acquire images.
Image File(s)
Activate this radio button to load images from files. You can enter the names of image files in the text field. Multiple file names are separated by a semicolon “;”. If an image with no path name or a relative path name is given, the image files are searched in the directories specified by the environment variables
HALCONROOT and HALCONIMAGES.
You can also enter the full path of an image directory to specify all images of the given directory. If the check box Recursive is ticked, the images of all subdirectories are specified as well.
Pressing <Return> will display the first of the specified images in the active graphics window.
The buttons Select File(s) ... and Select Directory ... open a file browser to select multiple images or an image directory, respectively. After clicking OK in the file browser, the text field is updated with the selected items, and the first image is displayed in the active graphics window.
Use the entry Snap or Live in the menu Acquisition, or the corresponding tool bar buttons to view the selected images one after another.
Image Acquisition Interface
Activate this radio button to acquire images from an image acquisition interface. The drop-down list contains the list of all supported image acquisition interfaces.
Clicking Detect probes the image acquisition interfaces in turn, and removes those interfaces from the list that do not respond. It is recommended to save your program before probing the image acquisition interfaces.
6.1.2
Tab Connection
Synopsis: Setup connection parameters for the image acquisition interface selected in the tab
This tab card is only available if the image source is set to an image acquisition interface. The connection parameters are described below. See the description of the operator open_framegrabber for additional information about the fields.
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Configuration
Device Select the ID of a board, camera, or logical device if multiple devices are available for the selected image acquisition interface.
Upon building the list of devices, the assistant queries the status of each device. Depending on the image acquisition interface, devices may be reported as misconfigured. If you select such a device, the assistant may suggest a Generic parameter that potentially resolves the misconfiguration. If you confirm this suggestion, the parameter will be entered into the Generic slot (see below). If a device is labeled with a question mark icon, it is either read-only, busy, or unknown.
Port Select the ID of the input port.
Camera Type Select a camera configuration or signal type.
Select... Select a camera configuration file (in XML format) from a file browser.
Trigger Tick the check box if the image acquisition is controlled by an external trigger.
Resolution (X / Y) Specify the factor for image width / height.
Color Space Specify the configuration for color acquisition.
Field Specify the frame selection for interlaced cameras.
Bit Depth Specify the number of bits used for one image channel.
Generic Some image acquisition interfaces support device-specific parameters to preset selected values before the camera is initialized. The parameters the interface claims to support are suggested as a drop-down list. To set a generic parameter, select it from the list, and edit the assigned value, i.e., the value after the =. Multiple generic parameters may be set by separating the entries with a comma.
If the selected image acquisition interface does not support generic parameters, this field is grayed out.
See the documentation of the individual image acquisition interfaces for more information about the supported generic parameters.
Action Buttons
Once the connection parameters are set up, the action buttons are used to connect to and acquire images from the specified device. Messages about connection errors are displayed in the status line of the image acquisition assistant window.
Connect Connect to the specified image acquisition device. If the connection fails, carefully check the configuration in the above fields. Not all combinations of settings are allowed for all devices.
It is recommended to enable low level error messages (see General Options -> Experienced
User) to find out what is going wrong. Please note that an established connection is closed automatically, if the connection parameters are modified.
When the connection is established, this button can be used to disconnect the device.
6.1.3 Tab Parameters
161
Snap Acquire a single image from the device (first connecting to the device if needed). The image is displayed in the active graphics window unless Display Image is set to Disabled.
Live Start/stop live image acquisition mode. The images are displayed in the active graphics window unless Display Image is set to Disabled. The live mode is stopped automatically if an error occurs.
Detect Clicking this button will attempt to redetect valid parameters for the current device.
Reset All Reset all connection parameters to their default values.
Image Display
The following display options are available:
Display Image It is recommended to set the display mode to Normal unless you wish to make speed measurements. Other modes are Volatile (volatile grabbing), and Disabled (grabbing images without displaying them).
Show frames per second during live acquisition Usually, the number of grabbed images and the acquisition time of the last image are displayed in the lower right corner of the window.
Ticking this check box causes the frame rate (frames per second) to be displayed in live mode.
6.1.3
Tab Parameters
Synopsis: Set parameters for the selected image acquisition device.
This tab card is available if the image source is set to an image acquisition interface and a connection to an image acquisition device has already been established. Press <F1> for more information about the displayed parameters.
Interface Library The image acquisition interface library (DLL or shared object) used by the current connection is displayed in this field.
Update Image If this check box is ticked, a new image is acquired immediately after each parameter change. Disable the check box if you want to change multiple parameters at once.
Refresh Refreshes the list of supported parameters and their value ranges. This is useful for parameters with side affects.
Reset All Resets all parameters to their default values. Individual parameters can be reset by clicking the corresponding button displayed to the right of each parameter.
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Parameter Grouping
The available parameters are grouped by user parameters, read-only parameters, action parameters and write-only parameters. The latter cannot be changed in the assistant and are listed only for reference.
The parameters of some of the interfaces are additionally grouped by category and visibility. If grouping information is available, the amount of displayed parameters can be reduced by choosing a subject matter from the down-down list Category. You can further filter the parameters by selecting a skill level from the down-down list Visibility (beginner, expert, or guru).
By default the parameters are sorted thematically. You can also sort the parameters by name (check box
Sort by Name).
Setting Parameters
The parameters are displayed in a tabular format. Hover the mouse pointer over a table row to get the short description of the corresponding parameter as a tool tip. The tool tip also includes the value range for numeric parameters (min.-max.).
The first column shows the parameter name. The second column depends on the parameter type:
• If the parameter is editable, its value can be entered into a text field. This field may contain value suggestions as a drop-down list. Numeric values can be incremented/decremented using the arrows next to the text field.
• If the parameter is read-only, its value is displayed, but cannot be modified.
• For action parameters, the corresponding action can be triggered by clicking the Apply button.
The third column is reserved for numeric parameters. It contains a slider to quickly alter the parameter value within the defined range. Please note that low level error messages are suppressed while dragging the slider. If the minimum value is below -10000, or the maximum value is above 10000, or no range is defined at all, no slider is displayed.
The fourth column contains a reset button for editable parameters. Click it to reset altered parameters to their default value.
6.1.4
Tab Code Generation
Synopsis: Preview / generate HDevelop program lines.
The settings made in the tab cards Source, Connection, and Parameters can be distilled to program lines that perform the desired image acquisition in your current program. The fields in this tab card specify the code generation details. You can preview the code lines in the panel Code Preview. This panel can be toggled between hidden and displayed state by clicking the button next to the panel label.
Acquisition
The settings of this section are available if images are acquired from an image acquisition interface.
Control Flow: The initialization code for the selected image acquisition interface is always generated
(setting Initialize Only). It opens a connection to the specified image acquisition device, and sets
6.1.5 Menu Bar 163
all changed parameters. You can also generate code to acquire a single image (setting Acquire Single
Image), or to acquire images in a loop (setting Acquire Images in Loop).
Acquisition Mode: You can switch between synchronous and asynchronous acquisition. The latter runs in the background and is recommended for continuous acquisition.
Variable Names
This section defines the variable names that are used in the generated code.
Connection Handle: Variable storing the acquisition handle. The image acquisition interface is accessed by this name. Set to AcqHandle in the example below.
Image Object: Variable used for the acquired images. Set to Image in the example below.
The following variables have to be specified if Source is set to Image File(s) and multiple files are specified:
Loop Counter: Variable storing the loop index.
Image Files: Variable for storing the image names as a tuple.
Generate the Code
Insert Code: The actual code is inserted at the IC.
Example Code
* Code generated by Image Acquisition 01 open_framegrabber (
'GigEVision', 1, 1, 0, 0, 0, 0, 'progressive', 8, 'gray', \
-1,
'false', 'default', '003053095003_Basler_scA160014gc', \
0, -1, AcqHandle) grab_image_start (AcqHandle, -1) while (true)
* grab_image_async (Image, AcqHandle, -1)
Do something endwhile close_framegrabber (AcqHandle)
6.1.5
Menu Bar
Menus File, Code Generation, Help
For the description of the corresponding menu entries see Common Features of all HDevelop Assistants.
Menu Acquisition
Connect Connect / disconnect the selected image acquisition device. See Tab Connection.
Snap Acquire a single image. See Tab Connection.
Live Acquire images in live mode. See Tab Connection.
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6.2
Calibration Assistant
6.2.1
Introducing the Calibration Assistant of HDevelop
Most applications that need a previous calibration of the camera system belong to the area of 3D machine vision. These applications require a 3D model of the camera system. Calibration is necessary in order to gain information about distortions (perspective and lens distortions) in an image and about parameters of the camera system. Calibrating your camera system with the HALCON Calibration Assistant enables you to measure in the world coordinate system with a high accuracy. This task can be performed by taking images of a known object, a calibration plate.
The Calibration Assistant of HDevelop is a front-end to HALCON’s operator camera_calibration.
Using the Calibration Assistant you can
• either perform a complete calibration or
• take advantage of the user-defined mode and only calibrate chosen parameters, if the rest is already known (e.g. if you are using a special setting).
All you need is a set of ideally 10 to 20 calibration images. The Calibration Assistant then returns the calibration results and enables you to generate code and insert it into a given program.
The Calibration Assistant can calibrate vision systems based on standard lenses as well as on telecentric lenses .
With the HALCON Calibration Assistant you can
• perform a
(page
• view the
(page
•
(page
178 ) for the calibration or for using the calibration results and insert it into a
program for further use in a subsequent application.
A reference to the elements of the Calibration Assistant can be found in the
Calibration Assistant Reference
(page
For further information about camera calibration, please refer to the corresponding chapter in the solution guide on 3D Vision.
ATTENTION: Remember that it is essential to keep your camera setup (aperture, focus, pose) fixed, once you have chosen it! This applies to the calibration process itself as well as to the subsequent application. Any changes will result in the failure of the calibration or - even worse - in wrong output values.
In this guide, the following special terms are used:
Calibration By
(page
169 ) a vision system, you extract information about it, e.g., its focal
length or its position and orientation relative to the "world". However, even with such information you cannot fully reconstruct the 3D world from a single image. For example, you can determine the (3D) size of an object only if you know its distance from the vision system (when using a standard lens). Calibration is a preparation for all subsequent image processing applications. The
6.2.1 Introducing the Calibration Assistant of HDevelop 165
Calibration Assistant needs to grab a set of images of a special calibration object placed in front of your vision system. You can choose between a Full Calibration and a User-Defined Calibration, where known parameters are not calibrated again.
Calibration Plate
(page
167 ) is an object whose shape is known precisely. Calibration plates are
available in different sizes. Transparent calibration plates are available for applications requiring backlight illumination. Which calibration plate is suited best depends on your machine vision task: As a rule of thumb, if you grab an image of the plane of measurement, it should fill a fourth of the image. For example, if an image of the plane of measurement corresponds to an area of 80mm x 60mm, you should choose the 30mm calibration plate. The bigger calibration plates (100mm and 200mm, made from aluminum) come together with a file containing their exact measurements (caltab_100mm.descr and caltab_200mm.descr). Please copy this file to the subdirectory calib of the HALCON base directory you chose during installation. This is not necessary for smaller (ceramics) calibration plates as they can be manufactured very precisely and can therefore use standard description files. If you use your own calibration plate, you have to create the description file yourself and copy it into the subdirectory calib.
Calibration Plate Extraction Parameters
(page
176 ) influence the extraction of the
calibration plate. You may change them in order to improve the extraction of the plate if necessary.
We recommend, however, that you try to improve your image quality first.
Camera Parameters Internal
(page
167 ) describe the camera itself, e.g., its
Focal Length, Cell Width and Cell Height. These parameters are part of the calibration results, initial values for some of them are also needed for the setup of the calibration.
Camera Pose The position and orientation of the world coordinate system relative to the camera are called the external
(page
167 ). They are part of the calibration results.
Display Parameters On the
(page
169 ) tab, you can choose the display parameters, like
colors, as you prefer them. See also
(page
Full Calibration In a
, the complete camera system is calibrated. The only infor-
mation needed are approximate values for Camera Type, Cell Width, Cell Height and Focal
Length as well as the question whether you are using a Telecentric camera (in which case the
Focal Length is not required).
Image Rectification Based on the calibration results, you can remove image distortions. This is called image rectification. Example code is available from the
(page
Pose Estimation Once the interior parameters are calibrated, it is possible to estimate the camera pose from a single image. Example code is available from the
(page
Reference Image This image locates the world coordinate system, which then has its origin in the middle of the calibration plate in the reference image. By default, the first calibration image is used as the reference image. However, you can choose any other image of the calibration sequence.
Standard Lenses A standard lens is similar to the one in the human eye: It performs a perspective projection ; hence, objects become smaller in the image the further they are away.
Telecentric Lenses Telecentric lenses perform a parallel projection. Therfore, objects have the same size in the image independent of their distance to a camera. This means that they can lie in different planes; only the orientation of the planes relative to the camera must be identical.
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User-Defined Calibration The setup step
provides a
User-Defined
Calibration, which enables you to perform calibrations with special setups or re-use parameters from previous calibrations.
World Coordinates Measurements and XLD contours can, after finishing the calibration, be transformed into (3D) world coordinates, meaning the coordinates of the world (e.g. in millimeters), as opposed to those of an image (in pixels). Example code is available from the Code Generation tab under
(page
Quality Issues A high quality of the calibration images is essential not only for the calibration itself but for the quality of the calibration results. Examples for bad image quality are overexposure of the calibration plate , bad mark contrast or very small mark size. These quality issues are listed under
(page
172 ) on the Calibration tab. Sorting out images with too many defects
improves the calibration results.
6.2.2
How to Calibrate with the Calibration Assistant
By using the Calibration Assistant, you can set up and optimize your calibration application in three steps:
•
Choose the right calibration mode ,
•
(page
• and
respond to image quality feedback
(page
6.2.2.1
Choosing the correct Calibration Mode and Basic Parameters
For the calibration setup in the Setup tab, the basic information has to be filled in. Which information is necessary for your application will depend on the answer to the question whether you want to perform a full calibration, whether you have a special setup or you have calibrated before and therefore want to take advantage of the user-defined calibration. Furthermore, information about the calibration plate and the camera is required.
In short, the setup information includes
• the
• the
• and the known
2 Choosing the task for your application
If you want to calibrate all parameters, e.g. if you are calibrating for the first time with your setup, click the radio button Full Calibration:
Pose and all Camera Parameters.
If you are using a special setting or you have already calibrated your system before and want to re-use your resulting parameters, choose User-defined:
Select Individual Parameters for
Calibration.
6.2.2 How to Calibrate with the Calibration Assistant 167
After having decided on your calibration task, proceed with the details about your
2 Calibration Plate Parameters
First, choose the description file for your calibration plate and the calibration plate Thickness (in mm).
The description file consists of the size of the plate, and you have to choose a filename ending with
"_old" if you are using an "old" plate without a black triangle in one of the edges (you can "update" your plate by drawing the triangle in one of the edges). With the parameter Thickness, you can modify the position of the world coordinate system and the measurement plane, which is located beneath the calibration plate surface by the value of Thickness in the
(page
Then proceed to set the
2 Set Camera Parameters
For setting up the camera parameters
• first choose the
• then
set the parameters for a full calibration
or
•
set the parameters for a user-defined calibration
(page
It is also possible to import parameters from a file. If you should decide to do this, just click the Import
Parameters button.
Once you have finished this last part of the Setup tab, proceed to the
(page
3 Choose your Camera Model
First choose the Camera Model you are using:
• either Area Scan (Division),
• Area Scan (Polynomial)
• or Line Scan
Even though the camera model Area Scan (Division) typically returns good results for your application, you can improve the accuracy and lower the error rate by using the Area Scan (Polynomial) camera model. We therefore recommend for you to use the Area Scan (Polynomial) model if the
Mean Error on the
(page
(page
decide for the Area Scan (Polynomial) model, it is especially important that you thoroughly cover the field of view with calibration plate images and do not leave out the edges.
Note, that a higher Mean Error might be caused by inappropriate calibration images.
3 Set Parameters for Full Calibration
If you choose a full calibration for an area-scan camera, you must specify approximate values for Cell
Width (Sx), Cell Height (Sy) and Focal Length . Please have a look at the data sheet of your camera for suitable values. Information about the Focal Length can be found on the lens itself.
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If your lens is telecentric, choose Telecentric, and the Focal Length will be grayed out.
If you have a line-scan camera, you must additionally specify approximate values for the motion parameters Motion x (Vx), Motion y (Vy) and Motion z (Vz).
6.2.2 How to Calibrate with the Calibration Assistant
3 Set Parameters for User-Defined Calibration
In the user-defined mode for the area-scan camera (division), you can also choose Center
Column (Cx), Center Row (Cy) and Kappa. The area-scan camera (polynomial) model allows you to also choose the lens distortion parameters for radial distortion Radial 2nd Order (K1),
Radial 4th Order (K2), Radial 6th Order (K3) and the two parameters for tangential distortion
Tangential 2nd Order (P1) and Tangential 2nd Order (P2).
If you want to change the parameters Cell Width and Cell Hight independently from each other, click the chain button.
6.2.2.2
Acquiring Calibration Images
The main part of the calibration process consists of acquiring images of the calibration plate in different positions and orientations relative to the vision system. Please note that the more you vary the position and orientation, the better the calibration results will be. Therefore, place the plate so that it appears in different corners, at different distances to the camera, and in different planes, i.e., tilt it for some images. Note that it is necessary to not only place the calibration plate in the center of the field of view, but also move it to the corners and margins. Good calibration images will improve your calibration results significantly. Detailed instructions on how to take calibration images can be found in the section
Acquiring Images for a Successful Calibration .
Obligatory steps for calibration are
• acquiring
• choosing your
(page
• and
(page
Optional parameters, which may be changed, are
• parameters concerning
(page
•
(page
•
Calibration Plate Extraction Parameters
(page
ATTENTION: Remember that it is essential to keep your camera setup (aperture, focus, pose) fixed, once you have chosen it! This applies to the calibration process itself as well as to the subsequent application. Any changes will result in the failure of the calibration or - even worse - in wrong output values.
Once the calibration images are available, you can push the Calibrate button and move on to the
(page
2 Acquiring Images for a Successful Calibration
Note that the calibration assistant currently only supports 8-bit (’byte’) images.
Steps that will improve your calibration results:
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Figure 6.1: Example for suitable calibration images.
1. Use a calibration plate that is big enough to fill a large part of the image (at least one fourth of the image’s total area).
2. The minimum diameter of the circular marks should be 10 pixels. To check this, move the mouse pointer over a calibration mark and examine whether the difference between the start and end position, as displayed in the row/column section of the Status Bar, is more than 10 pixels.
3. Use an illumination where the background is dark and the calibration plate is bright.
4. The white background of the calibration plate should have a gray value of at least 100. You can check the gray value of an area by moving the mouse pointer on the particular area in the graphics window. The gray value is then displayed in the HDevelop Status Bar.
5. The contrast between the foreground and the background of the calibration plate, i.e., its bright and dark parts, respectively, should be better than 100 gray values.
6. Use an illumination where the calibration plate is represented with homogeneous gray values.
7. The images must not be overexposed, which means that they should not have a peak at 255 in the histogram. You can use the Live mode and run the tests, which can be found under Quality
Issues, to check that no part of the calibration plate is totally white. Another option is checking the gray values in the status bar as described above. If your image is too bright, close the lens aperture a bit more or use an illumination that is less bright. If your image is too dark, use a brighter illumination or open the lens aperture a bit more until you achieve a satisfying image from which the marks can be segmented easily. Then, push the Snap button to keep your image.
8. In this way, cover the whole field of view with multiple images, i.e., position the calibration plate in all areas of the field of view (upper left corner, upper right corner, lower left corner, lower right corner and image middle). Do not forget to also take images right in the corners and along the margins of the field of view.
9. Use various orientations of the calibration plate: Use at least four images with different tilt in every direction as shown in
(we recommend to tilt the plate in every quadrant of the image twice and vary the tilting direction).
10. In total you should acquire at least 10, better 15 to 20 images.
6.2.2 How to Calibrate with the Calibration Assistant
2 Choosing an Image Source
The images for the calibration can either be loaded from a file or acquired directly using the Image
Acquisition Assistant.
When loading images from a file, just click the radio button Image Files.
To acquire new images, click the radio button
(page
tant will then appear in a new window and support you with acquiring new calibration images.
Note that the calibration works on a single channel. For color RGB images, the red channel will be used.
A color transformation can be performed with the operator trans_from_rgb.
2 Calibration
The three basic steps of each calibration are
•
acquiring calibration images ,
•
selecting a reference image , and
•
3 Calibration Images
All images from files will be displayed with their path on the Calibration tab, whereas images acquired using the Acquisition Assistent will be displayed with their consecutive numbers. Furthermore, the image status gives information about the quality of each image. Details concerning quality can be found under
. If you use the Image Acquisition Assistant and want to see a live image,
you can also activate Live Image on the Calibration tab and click the Snap button whenever you want to keep an image for calibration. If you Load... images from a file into the Calibration Assistant and then decide to acquire new images with the Image Acquisition Assistant, you will be warned that the images from the file will be removed from the window. With the Remove and Remove All buttons on the left, you can remove either one or all images of the list. The Save and Save All buttons will save one or all images of the list. Click Update to control the time when camera parameters, segmentation parameters or quality adjustments shall be transferred for the existing images. Activate Auto Update to automatically update to the latest adjustments. Quality Issues are updated with a little delay after adapting
Calibration Plate Extraction Parameters
(page
176 ). Deactivating Auto Update
enables you to change several parameters at once and speeds up the processing bigger data sets.
3 Select a Reference Image
With the pose of the calibration plate in the reference image, you specify the world coordinate system and the measurement plane for subsequent 3D measurements (see
). Thus, in one calibration image
(typically, the first one), you should place the calibration plate such that it lies on top of the measurement plane. If this is not possible, place the calibration plate in a position parallel to the measurement plane and "move" the coordinate system by adapting the parameter Thickness. The star on the left side of the Calibration window indicates the reference image. It is by default set on the first image. You can, however, by clicking the Set Reference button, pick another image as reference.
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Figure 6.2: Calibration plate image with coordinate system.
3 Calibrating
Click the button Calibrate to finally perform the calibration task. You should, however, check first whether you have 10 to 20 images that are of sufficient quality. You can check the quality under
. If necessary, you can also change
Calibration Plate Extraction Parameters
(page
176 ) before actually calibrating. In case your calibration fails and displays the error "Camera
calibration did not converge", check possible error sources in the
Checklist for Calibration Errors
(page
2 Handling Quality Issues
Under Quality Issues you find an evaluation of each image, which includes descriptions of the defective image features and a quality percentage that tells you how severe the problem is. A result of
0% indicates a very defective image feature whereas 100% equals ideal quality. This can help you to improve your calibration result by deleting images which are not good enough and might lead to a higher error rate during the calibration process. If you need a certain quality level you can set a Warn Level and the defects will be listed under Quality Issues. The quality issues are detected by image tests and sequence tests. If you want the program to run faster or if you do not need quality feedback, you can change Image Tests and Sequence Tests either to Quick, which performs less tests, or None, which does not perform any tests at all. If the defects are too severe e.g. if the calibration marks or the even the calibration plate are not found, the Calibration button will be grayed out, making it impossible to calibrate unless all images of such poor quality are deleted from the list.
The test results referring to the calibration plate’s tilting may be ignored if later measurements are always conducted in exactly the same plane. In this case, however, the values for the Focal Length and Z are not correct each for itself but only in their combination. The reason for this is that neither of these values can be determined for itself which leads to the result that if you get, for example, a Focal Length that is double the value that it should be, Z will be half as high and vice versa. Besides, the further you place an object above the plane in which you have performed the calibration, the less precise the result will be.
Note that poor image quality leads to poor calibration results and subsequently causes bad or wrong measuring values. However, acceptable results are usually achieved even with quality warnings in the
6.2.2 How to Calibrate with the Calibration Assistant 173
Possible Error Source
Did any camera settings (like aperture, focus or pose of the camera) change during the calibration process?
Solution
Take new calibration images and do not change any settings during calibration and later during the application. If you decide to change anything you have to start a new calibration.
Did you acquire the calibration images the way they are required?
Check if you have acquired 10 to 20 images, if the calibration plate has been positioned everywhere in the field of view and if it has been tilted in every direction. If you are unsure about how to take good calibration images, read the
(page
Are you using an extreme wide angle lens?
The distortions that appear close to the image borders cause a higher Mean Error or can even be responsible for the failure of the calibration. You must use another lens in this case.
Is the size of your camera chip compatible with the lens?
Using a lens that is not compatible with your camera chip size (this information should be included in the instructions of the lens) will decrease the quality of your image.
Table 6.1: Checklist for Calibration Errors.
range of 40% to 70%. If necessary check the following tables for suggestions about improving your image quality. When trying to improve your image quality, do not forget to check other
ATTENTION: Remember that once you change your camera setup (aperture, focus, pose) either during the calibration process or during the subsequent application, you have to restart your calibration with the new setup. Any changes will result in the failure of the calibration or - even worse
- in wrong output values.
Note: Due to special settings or unchangable specifications of your work environment, it may be possible that you cannot fully avoid any quality reductions. If you follow these instructions, you should, however, be able to reach a feasible quality level to work with.
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Quality Issue
Plate is overexposed
Explanation
The image is too bright, it reaches the highest gray value
(255) in some parts. This leads to a shifting of edges and therefore calculates a wrong center position.
Possible Solution
Close the lens aperture or the shutter a bit more or turn down the brightness of your illumination until an adequate quality is reached.
Illumination is inhomogeneous The image is illuminated inhomogeneously, i.e. the brightness of the calibration plate changes within one image.
This condition makes it difficult to locate the calibration plate and consequently leads to a lower accuracy.
Inhomogeneity in an image is often the result of using lateral illumination. If that is the case: Can you change the setting and instead use illumination from above? Another possibility would be to use diffuse illumination.
Contrast is low The difference between the gray values of the calibration plate and the calibration marks is not big enough.
Reasons can be either overexposure or underexposure.
To improve your results, change your aperture or the brightness of your illumination.
Plate in image is too small The plate size is too small in relation to the image size.
The object should cover approximately one fourth of the image’s total area. Mount the camera closer to the object, use a longer focal length or use a larger calibration plate.
Marks on plate are out of focus The marks are not completely focussed, some of them appear blurry. This leads to a lower robustness.
The depth of field has to include the whole object. To fix this error, change either your focal length or the distance of the object to the camera. Alternatively you can also make the aperture smaller and use brighter illumination.
Quality assessment failed The image test failed, even though the plate could be found in the image.
Check, if any part of the image is occluded and if the occlusion interrupts the black margin of the calibration plate.
6.2.2 How to Calibrate with the Calibration Assistant 175
Quality Issue
Mark extraction failed for some images
Explanation
It was impossible to extract the calibration plate marks in some images, which makes it also impossible to calibrate in this state.
Possible Solution
Delete the images for which mark extraction has failed and use new images instead or adapt the exteraction parameters. Make sure that you follow the
steps for good calibration images
(page
check for
(page
Quality issues detected for some images
The quality of some images is below the warn level.
Check the quality issues of the single images by clicking on their names in the list.
Handle quality issues as described in the table above.
Number of images is too low
The number of images is lower than recommended.
Check if you have taken enough images. Less than 10 images will lead to a low percentage in the quality ranking whereas 20 images equal 100 percent.
Field of view is not covered by plate images
Some part of the field of view is not covered by any image of the calibration plate, i.e. there are areas with no marks.
Press the Show button, which appears in a column named
Details, to see all areas in red that are not covered by calibration plate images (compare
Before continuing, add the missing image(s) to your sequence.
You can avoid this problem by following the
steps for good calibration images
(page
Tilt angles are not covered by sequence
The calibration plate has not been tilted enough.
Add more images of your calibration plate tilted in different directions. We recommend to tilt the plate in every quadrant of the image twice and vary the tilting direction.
Not all image sizes are identical
The image list contains images of different sizes.
You have changed your setup while taking calibration images.
Therefore, you should delete those images taken before the change in order to get useful results back.
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a) b) c) not covered covered d)
Figure 6.3: Not enough calibration images have been taken. a) and b): calibration sequence consisting of two calibration plate images c) A Show button appears due to the fact that the coverage is not sufficient. d) An image shows which parts of the field of view are not covered by calibration plate images.
6.2.2.3
Display Parameters
The drop-down menus under Display Parameters enable you to choose the the colors and drawing parameters for the calibration images display that you prefer. You can either leave the default values or choose your own values for Plate Region, Mark Centers or the Coordinate System. The Draw option lets you choose whether you want to see margins or filled regions.
6.2.2.4
Calibration Plate Extraction Parameters
You should always aim for high quality images. If for some reason you should, however, have trouble with your image quality and see no other option of improving it, you can still adapt some parameters under Calibration Plate Extraction Parameters. There are three groups of parameters which may be changed:
• Locating the Calibration Plate, including Filter Size, Mark Threshold and Minimum Mark
Diameters,
• Extracting the Mark Regions, including Initial Threshold, Threshold Decrement and
Minimum Threshold, and
6.2.3 Results of the Calibration 177
• Extracting the Mark Contours, including Smoothing (Alpha), Minimum Contour Length and
Maximum Diameters.
For more information about the first group of parameters, please refer to the reference manual entry of the HALCON operator find_caltab. Groups two and three equate to HALCON operator find_marks_and_pose.
6.2.3
Results of the Calibration
Two types of parameters of your vision system are calculated as results: internal parameters, e.g., the precise focal length, the size of the camera chip, or the distortion caused by an imperfect lens, and external parameters, i.e., the position and orientation of the vision system.
Consequently, the calibration returns the following results:
•
•
• the
The results displayed in Camera Parameters and Camera Pose can also be saved to a file by clicking the Save buttons on the right.
enables you to choose which results should be displayed.
Once you are finished with the results, go on to the
(page
6.2.3.1
Calibration Status
This box displays the Status of the calibration, i.e. whether the calibration was successful, and the
in pixels.
If you either delete
(page
(page
(page
167 ) after having calibrated, the former calibra-
tion data is not valid any more. Therefore, the Status will display that no calibration data is available.
To continue working with your changed camera parameters, calibration parameters or images, just click
(page
172 ) again on the Calibration tab.
2 Mean Error
Mean Error designates the average error in pixels during the calibration process. Once the system has been calibrated, the ideal centers of the calibration marks are calculated and compared to the real mark centers. Mean Error is the deviation value between the ideal and the real mark centers. A value of 0.1
and lower can be regarded as a good result. Possible calibration errors are described in the tables about quality issues under
(page
172 ); most of them can usually be solved quite easily, often
just by taking
(page
178 HDevelop Assistants
6.2.3.2
Camera Parameters
The internal camera parameters include Cell Width (Sx) and Cell Height (Sy) in micrometer,
Focal Length in mm, Center Column (Cx) and Center Row (Cy), Image Width and Image
Height in pixels. They also include Kappa in 1/ m
2 or instead of Kappa, the distortion parameters
Radial 2nd Order (K1) in 1/ m
2 m
6
, Radial 4th Order (K2) in 1/ m
4
, Radial 6th Order in
, Tangential 2nd Order (P1) and Tangential 2nd Order (P2) in 1/ m
2 for the polynomial area-scan camera model.
If you have a line-scan camera, additionally to the values of the area-scan camera
(division)model, values for the motion parameters Motion x (Vx), Motion y (Vy) and Motion z (Vz) in micrometer/pixel will be returned.
6.2.3.3
Camera Pose
The 3D pose of the world coordinate system relative to the camera is described by the external camera parameters X, Y and Z in mm and Rotation X, Rotation Y and Rotation Z in degrees.
6.2.3.4
Display Results
Via radio buttons you can choose Original Reference Image, to see the previously chosen reference image and Simulated Reference Image to display a synthetic reference image, which has been calculated using the internally known measures of the calibration plate and the pose of the plate in the reference image. You can also decide whether or not you want to Display Coordinate Axes of the coordinate system of the calibration plate.
6.2.4
Generating Code
This tab helps you to generate and insert code for calibrating and for using the calibration results in your
HDevelop program. The tab is subdivided into four parts:
•
•
•
(page
•
(page
Once you are finished with configuring the options, check the position of the insert cursor and click
(page
183 ) under Calibration or Sample Usage to insert the code into your HDevelop
program. Note that if you have already inserted code into your program and you click insert code again, the previous code will be replaced regardless of the cursor position.
6.2.4 Generating Code 179
6.2.4.1
Calibration
Choose your Export Mode, either
• Calibration Procedure which exports the generated code,
• Calibration Data (Tuple) which exports the resulting calibration parameters
(CameraParameters and CameraPose) as tuples,
• or Calibration Results (File) which writes the calibration results into the specified files and generates code lines for reading those files.
For the last one you can click the folder icons to browse for a stored file. Subsequently select Parameter
File and Pose File.
In order to save the calibration results to files it is necessary that
• a successful calibration took place before and
• a file name exists for both files.
To generate code for initializing the image acquisition when using the
(page
158 ), enable Initialize Acquisition.
Once you are finished, check the position of the insert cursor and click
(page
insert the code into your HDevelop program.
6.2.4.2
The Browse button
The Browse button on the Code Generation tab is similar to the Save button on the Results tab.
It can be used in order to create file names into which the calibration results can then be written when choosing the option Calibration Results (File).
6.2.4.3
Sample Usage
Sample Usage shows you what is possible with your calibration data and provides code, which you can adapt to your own purposes. Choose the action you are interested in and the example code will be inserted into your program.
You have the choice between:
•
Transform Measurements into World Coordinates
•
Transform XLD Contours into World Coordinates
•
Estimate Pose from Single Image
and
•
.
Once you are finished, check the position of the insert cursor and click
(page
insert the code into your HDevelop program.
180 HDevelop Assistants
2 Transform Measurements into World Coordinates
In the example code, the image coordinates of the first two mark center points are transformed into world coordinates and this (3D) distance is calculated. First, the image coordinates of some points of interest lying in the reference plane are obtained. Here, simply the first two mark center points of the plate are chosen and a line is drawn between the two points for visualization. Then image coordinates are converted into world coordinates using HALCON operator image_points_to_world_plane. The Z coordinates will be 0 by definition because the measurement plane is the plane with the world coordinate
Z=0 (on reference plane). The distance in world coordinates is determined using distance_pp.
To adapt this code to your application, you typically exchange the mark centers for "real" points of interest.
2 Transform XLD Contours into World Coordinates
In the example code, the XLD contours are transformed into world coordinates and this (3D) distance is calculated. The points are visualized by a line. First an XLD in image coordinates, which relates to some interesting features in the image, is obtained. Here, we simply generate a contour connecting the mark center points of the plate by using the HALCON operator gen_contour_polygon_xld. Then a convertion into world coordinates is performed with HALCON operator countour_to_world_plane_xld.
Using the operator get_contour_xld, mark center points are extracted in world coordinates.
To adapt this code to your application, you typically exchange the mark centers for "real" points of interest and adapt or remove the visualization.
For further information about pose estimation, please refer to the section "Pose Estimation of known 3D
Objects With a Single Camera" in the Solution Guide III-C.
2 Estimate Pose from Single Image
First, the position of mark centers on the calibration plate is determined. With known camera parameters, one image is enough to determine the new pose using the HALCON operator camera_calibration.
This sample code always determines the pose of the calibration plate. There is no further adaption possible.
2 Rectify Image
First the desired width of the visible area in world coordinates in mm is chosen and converted to m.
Then set_origin_pose adjusts the origin so the plate is roughly centered. The HALCON operator gen_image_to_world_plane_map generates the rectification map. Finally, images can be rectified using the rectification map by map_image.
To adapt this code to your application, you typically change the scale and origin of the new image coordinate system.
6.2.4.4
Variable Names
For each calibration, default variable names are chosen. You can, however, use your own variable names and change variable names for:
6.2.5 Calibration Assistant Reference 181
• Connection Handle
• Image Object
• Camera Parameters
• Start Parameters
• Loop Counter
• Image Files
• Camera Pose
• Window
Note: These are variables which you might set before the generated code or use after the generated code.
Intermediate variables have fixed names starting with TmpCtrl or TmpObj.
Once you are finished, check the position of the insert cursor and click
(page
insert the code into your HDevelop program.
6.2.4.5
Code Preview
Here, you can, e.g., edit or replace individual operators of the code lines proposed by the Calibration
Assistant.
For details, see also
(page
6.2.5
Calibration Assistant Reference
The Calibration Assistant consists of the following elements.
Pull-down menus:
•
•
(page
•
(page
•
(page
Tool bar with a selection of important buttons:
•
•
Save Current Assistant Settings
•
(page
•
(page
•
(page
Tabs with the dialogs for most of the tasks that can be done with the Calibration Assistant:
182 HDevelop Assistants
•
(page
•
(page
•
(page
•
(page
Furthermore, it provides a status bar at the bottom in which messages are displayed. The status bar also displays the
(page
177 ), i.e., if the calibration was successful. Please note that the
status bar does not provide a scrolling mechanism; if the displayed message is too long, move the mouse over it, so that a tool tip displaying the full message pops up. Alternatively, if the message is only slightly larger than the status bar, you can also drag the left or right border of the Calibration Assistant window to enlarge it.
Images are displayed in the graphics window of HDevelop.
6.2.5.1
The Menu File
Via the menu File you can
•
load formerly used and saved settings
of the Calibration Assistant,
•
of the Calibration Assistant for later use,
•
the Calibration Assistant dialog (while retaining the current settings as long as the HDevelop session is active), and
•
the Calibration Assistant dialog (discarding the settings).
2 Loading Assistant Settings
If you have
the settings of a former Calibration Assistant session, you can load them again by the menu item File . Load Assistant Settings or via the corresponding button of the tool bar.
2 Save Current Assistant Settings
You can save the current settings of a Calibration Assistant session using the menu item File . Save
Current Assistant Settings or the corresponding button in the tool bar. Then, you can
them again in a later session.
2 Close the Calibration Assistant Dialog
When closing the Calibration Assistant dialog with the menu item File . Close Dialog, the current settings are stored for the duration of the current HDevelop session. That is, as long as you do not exit
HDevelop, you can again open the Calibration Assistant with the same settings. In contrast to this, when you
the Calibration Assistant, the settings are lost also for the current HDevelop session.
2 Exit the Calibration Assistant
6.2.5 Calibration Assistant Reference 183
When you exit the Calibration Assistant with the menu item File . Exit Assistant, the assistant’s dialog is closed and the current settings are lost unless you have stored them via the menu item File .
Save Current Assistant Settings
(page
190 ). If you want to close the dialog but keep its settings
for the current HDevelop session, you should use the menu item
instead.
6.2.5.2
The Menu Calibration
Via the menu Calibrate you can run a calibration as described in the section
(page
6.2.5.3
The Menu and Tab Code Generation
Via the menu Code Generation you can
•
to the program window of HDevelop according to the current settings of the Calibration
Assistant,
•
release the generated code lines
in the program window,
•
delete the generated code lines
from the program window as long as you did not release them, and
• open the dialog for the
inside the tab Code Generation.
2 Insert the Generated Code Lines
Via the menu item Code Generation . Insert Code (also accessible as tool bar button or as button inside the tab Code Generation), you can insert the code that is generated according to the current settings of the Calibration Assistant into the program window. Inserting code via menu or tool bar will generate code for calibration and samples.
2 Release the Generated Code Lines
Via the menu item Code Generation . Release Generated Code Lines you can release the generated and inserted code lines. After releasing the code lines, all connections between the Calibration
Assistant and the program window of HDevelop are lost. That is, changes, e.g., the deletion of code lines, can then only be applied directly in the program window and not from within the Calibration Assistant anymore.
2 Delete the Generated Code Lines
Via the menu item Code Generation . Delete Generated Code Lines you can delete the code lines that you have previously generated and
into the program window of HDevelop from within the Calibration Assistant. Note that this works only as long as you have not yet
the code lines.
2 Preview of the Generated Code Lines
Via the menu item Code Generation . Show Code Preview you can open the dialog for the Code
Preview in the tab Code Generation.
184 HDevelop Assistants
6.2.5.4
The Menu Help
Via the menu Help you can access the online documentation.
6.2.5.5
The Tab Setup
The Setup tab consists of the following subdivisions:
•
(page
•
(page
•
(page
6.2.5.6
The Tab Calibration
The Calibration tab includes:
•
(page
•
(page
•
(page
•
(page
•
Calibration Plate Extraction Parameters
(page
6.2.5.7
The Tab Calibration Results
The Calibration Results tab includes the following subdivisions:
•
(page
•
(page
•
(page
•
(page
6.3 Matching Assistant
6.3
Matching Assistant
6.3.1
Introducing the Matching Assistant of HDevelop
The Matching Assistant of HDevelop is a front-end to HALCON’s powerful shape-based matching, which lets you locate objects with sub-pixel accuracy at a high speed, even when they appear rotated, partly occluded, or under changing illumination. Using the Matching Assistant you can
• configure and test the matching process with a few mouse clicks and
• optimize the parameters interactively to get the maximum matching speed and recognition rate.
All you need is a single model image and a set of test images. The Matching Assistant further assists you by automatically calculating suitable parameter values based on your selections.
How to use the Matching Assistant is described
A reference to the elements of the Matching Assistant can be found
(page
In this online help, the following special terms are used:
Matching Matching is the process of locating an object described by a model in an image. The results of the matching process are the position and orientation of the object and the matching score.
Model In order to locate an object, you must provide the Matching Assistant with an example image of the object. From this, the Matching Assistant creates the so-called model, an internal representation of the object containing only the information characterizing the object. This representation is then used when searching for the object in the test images.
Model Image This is the image containing your example of the object to be searched for. This image should be a characteristic image of the object, i.e., the object should appear in its default position and orientation and not be occluded; furthermore, the image should not contain clutter. You can open this image via the menu item File .
(page
Model Region of Interest (ROI) This is the region in the model image which contains the object to be found. You can mark this region via the menu item Create Model .
(page
Test Image You can test the performance of the matching process by providing test images via the menu item Use Model . Test Images .
(page
representative images from your matching application, i.e., the object should appear in all allowed variations of its position, orientation, occlusion, and illumination.
Score When comparing a region in a test image with the model, the Matching Assistant calculates a measure of similarity, the so-called score, which ranges between 0 (no similarity) and 1 (perfect similarity).
6.3.2
How to Use the Matching Assistant of HDevelop
By using the Matching Assistant, you can set up and optimize your matching application quickly and easily in three steps:
185
186 HDevelop Assistants
•
•
•
We recommend to reset all parameters via the button
(page
(page
190 ) before starting with a new matching application.
6.3.2.1
Creating the Model
A
(page
185 ) is created in three steps:
• Open the so-called
(page
185 ) via the menu item File .
(page
189 ), the corresponding button in the tool bar, or the text field and button of Model Image inside
the tab Model Creation.
• Create an
(page
185 ) around the object either via the menu items at Create Model .
(page
190 ) or via the corresponding buttons inside the tab Model Creation.
• Specify the parameter
(page
193 ) inside the tab Model Creation (accessible also
via Create Model .
(page
192 )) so that the model consists of
enough points to be recognizable.
Alternatively, you can
(page
(page
190 ) with the Matching Assis-
tant or HALCON.
Now, you can
on
(page
6.3.2.2
Testing the Model
After you
the
(page
185 ) you test it in the following steps:
• Load one or more
(page
185 ) via the menu item Use Model . Test Images .
(page
200 ) or via the button Load inside the dialog Test Images in the tab Model
Use.
• Specify standard search parameters via the menu item Use Model .
(page
203 ), which opens the corresponding dialog in the tab Model Use. Espe-
cially the
(page
204 ) to search for in an image should be specified. If
the number of object instances varies from test image to test image, you can
specify the number of visible objects
(page
202 ) for each image separately; in this case the search parameter mentioned
above should be set to 0 or to the maximum number of visible objects.
•
Assure that all objects are found
(page
Now, you can optimize the speed of the matching process by
6.3.2 How to Use the Matching Assistant of HDevelop 187
6.3.2.3
Optimizing the Parameters
After you configured the
(page
185 ) process such that the search is successful in all test images,
you can start to optimize the parameters to speed up the matching as far as possible.
To support this process, the Matching Assistant allows to optimize the search parameters
(page
(page
204 ) automatically via the menu item Use Model .
(page
206 ), which can be accessed also via the tab Model Use.
If the reached recognition speed is not sufficient, you can try to modify parameters manually. However, please be aware that such a modification may result in a lower accuracy of the calculated position, orientation, or scale, or even prevent the Matching Assistant from finding the object! Therefore, we recommend to check whether the matching still succeeds in all
(page
185 ) after each modification.
How the different parameters influence the recognition speed is described below. Please note that whenever you modify a model parameter, the internally stored model must be created anew; you must start this creation (and the search) explicitly using the button Find Model or the button Detect All in the tab Model Use. After each modification determine the resulting recognition speed using the dialog
(page
The following modifications can speed up the matching processes:
Create Model .
(page
• Number of
(page
Increase the value and check whether the matching still succeeds in all images.
• Allowed
(page
(page
Set the parameters
(page
(page
(page
(page
(page
(page
195 ), according to the ranges probably needed for your images.
Create Model .
(page
•
(page
Increase the value and check whether the matching still succeeds in all images.
•
(page
Select a higher reduction rate and check whether the matching still succeeds in all images.
•
(page
(page
Increase the values and check whether the matching still succeeds in all images. Please note that the accuracy may suffer if you increase the step size!
Use Model .
(page
•
(page
If your application doesn’t require sub-pixel accuracy, you can speed up the matching by selecting the value ’none’.
(page
188 HDevelop Assistants
Increase the value and check whether the matching still succeeds in all images. Note that as a result of this modification wrong instances of the model may be found. Furthermore, the accuracy of the calculated position, orientation, and scale may decrease.
6.3.3
Matching Assistant Reference
The Matching Assistant consists of the following elements.
Pull-down menus:
•
•
(page
•
(page
•
(page
•
(page
•
(page
Tool bar with a selection of important buttons:
•
(page
•
Save Current Assistant Settings
(page
•
(page
•
•
(page
•
(page
•
(page
Tabs with the dialogs for most of the tasks that can be done with the Matching Assistant:
•
(page
•
(page
•
(page
•
(page
Furthermore, it provides a status bar at the bottom in which messages are displayed. The status bar also displays the matching results, i.e., the number of found instances, the needed time, and for each found instance the position, orientation, scale, and score. Please note that the status bar does not provide a scrolling mechanism; if the displayed message is to long, move the mouse over it, so that a tool tip displaying the full message pops up. Alternatively, if the message is only slighly larger than the status bar, you can also drag the left or right border of the Matching Assistant window to enlarge it.
Images and models are displayed in the graphics window of HDevelop.
6.3.3 Matching Assistant Reference 189
6.3.3.1
The Menu File
Via the menu File you can
•
•
load an already existing shape model ,
•
•
load formerly used and saved settings
of the Matching Assistant,
•
of the Matching Assistant for later use,
•
the Matching Assistant dialog (while retaining the current settings as long as the HDevelop session is active), and
•
the Matching Assistant dialog (discarding the settings).
2 Opening the Model Image
The so-called
(page
185 ) is used to create the model
(page
185 ) of the object you want to
find later. This image should be a characteristic image of the object, i.e., the object should appear in its default position and orientation and not be occluded; furthermore, the image should not contain clutter.
When you select the menu item File . Open Model Image or press the corresponding button either in the tool bar or in the dialog Model Image in the tab Model Creation, a standard file selection box appears. The Matching Assistant can read the image file types TIFF, BMP, GIF, JPEG, PPM, PGM,
PNG, and PBM.
The selected image is displayed automatically. Typically, the next step is to
around the object.
As an alternative to loading a model image and
(page
item File .
can be used to load a model that you have
with the Matching Assistant or HALCON.
Note that the matching works on a single channel. For color RGB images, the red channel will be used.
A color transformation can be performed with the operator trans_from_rgb.
2 Loading a Shape Model
As an alternative to
a
(page
(page
(page
interactively, the menu item File . Load Model or the corresponding button Load in the tab Model
Use can be used to load a model that you have
with the Matching Assistant or HALCON.
Note that when you load the model from a file, all the menu items, buttons, and dialogs that enable you to change the model parameters or display the model image will not be selectable because a loaded model cannot be changed and contains no information about the image from which it was created. Thus, e.g., the menu items Create Model .
(page
(page
of the dialog accessed by Create Model .
(page
inspect the model, are enabled.
190 HDevelop Assistants
2 Saving a Shape Model
The menu item File . Save Model enables you to save the
(page
use. For example, the
(page
185 ) can be loaded into the Matching Assistant again in a later session
with File .
(page
2 Loading Assistant Settings
If you have
the settings of a former Matching Assistant session, you can load them again by the menu item File . Load Assistant Settings or via the corresponding button of the tool bar.
2 Save Current Assistant Settings
You can save the current settings of a Matching Assistant session using the menu item File . Save
Current Assistant Settings or the corresponding button in the tool bar. Then, you can
them again in a later session.
2 Close the Matching Assistant Dialog
When closing the Matching Assistant dialog with the menu item File . Close Dialog, the current settings are stored for the duration of the current HDevelop session. That is, aslong as you do not exit
HDevelop, you can again open the Matching Assistant with the same settings. In contrast to this, when you
the Matching Assistant, the settings are lost also for the current HDevelop session.
2 Exit the Matching Assistant
When you exit the Matching Assistant with the menu item File . Exit Assistant, the assistant’s dialog is closed and the current settings are lost unless you have not stored them via the menu item File
.
Save Current Assistant Settings
. If you want to close the dialog but keep its settings for the
current HDevelop session, you should use the menu item
instead.
6.3.3.2
The Menu Create Model and the Tab Model Creation
Via the menu Create Model as well as the tab Model Creation you can
•
•
display the image pyramid , and
• specify
(page
(page
In the tab Model Creation you can additionally
(page
2 Creating a Region of Interest Around the Object
Via the menu items in Create Model . Create ROI or the corresponding buttons in the tab Model
Creation you can mark the region that serves as the model by drawing it on the displayed model image.
6.3.3 Matching Assistant Reference 191
The Matching Assistant provides different
(page
185 ) shapes: axis-parallel and arbitrarily oriented
rectangles, circles and ellipses, as well as free-form shapes including polygons.
You draw rectangular, circular, and elliptic ROIs as follows: Select the corresponding drawing mode and click into the image. Then, move the mouse over the object while keeping the left mouse button pressed; the selected shape appears. After releasing the mouse button you can move the ROI by dragging its center
(marked with a cross) with the left mouse button. Furthermore, you can edit the shape by dragging its boundaries. You finish the creation by clicking once with the right mouse button or by clicking the Stop button in the tool bar of the main window.
By selecting the menu item Create Model . Create ROI . Arbitrary Region or the corresponding button in the tab Model Creation you can create polygons and free-form shapes. To create a polygon click with the left mouse button to mark each corner point; a click with the right mouse button closes the polygon and finishes the creation. To create a free-form ROI draw it directly while keeping the left mouse button pressed; a click with the right mouse button closes the shape and finishes the creation.
Note that in both cases you cannot edit the ROI after its creation!
In order to create an optimal model, please assure that the region of interest contains only characteristic parts of the object and no clutter!
After creating an ROI, you can specify
standard model parameters . Typically, you now select what contrast
(page
193 ) the points must have in order to be included in the model.
2 Displaying the Model Image
Pressing the button Display Model in the tool bar of the Matching Assistant, you can display the model image if available (if you
(page
189 ) from file, the model image is not available).
You can alternatively display the model image via the button Display in the dialog Display Image
Pyramid of the tab Model Creation (accessed also via the menu item Create Model . Display
Image Pyramid). If you already created a model
(page
185 ), the model itself is displayed as well.
When increasing the values for Image and Model using the sliders or the text boxes, you can display the pyramid levels (see the
corresponding section about pyramid images ).
2 Displaying the Image Pyramid
Using the dialog Display Image Pyramid (accessed via the menu item Create Model . Display
Image Pyramid or directly inside the tab Model Creation), you can display the
(page
how to display the model image ) and inspect the pyramid of models and the corresponding
images by
• selecting which
is displayed,
• selecting which
is displayed, and
•
model and image level.
2 Displaying the Model on the Different Pyramid Levels
You can select the desired pyramid level of the model by using the slider or text box for Model inside the dialog Display Image Pyramid of the tab Model Creation. The model is overlaid onto the pyramid
192 HDevelop Assistants
image selected with the slider or text box
within the same dialog. By default, the model and the image are displayed on the same pyramid level; you can unlock and again lock the levels using
right to the sliders.
Note that the highest available pyramid level is determined automatically by the Matching Assistant based on the size of the model
(page
185 ); depending on the selected
and
(page
194 ), higher pyramid levels may not contain any model points.
Detailed information about the model image pyramid can be found
(page
2 Displaying the Model Image on the Different Pyramid Levels
You can select the desired pyramid level of the model image using the slider or text box for Image inside the dialog Display Image Pyramid of the tab Model Creation. Onto this image, the model on the pyramid level selected with the slider or text box for
(page
191 ) within the same dialog is overlaid.
By default, the model and the image are displayed on the same pyramid level; you can unlock and again lock the levels using
right to the sliders.
Note that the highest available pyramid level is determined automatically by the Matching Assistant based on the size of the model
(page
185 ); depending on the selected
and
(page
194 ), higher pyramid levels may not contain any model points.
Detailed information about the model image pyramid can be found
(page
2 Locking the Display of Model and Image Pyramid
By default, the pyramid levels of the displayed
(page
are locked. When pressing the unlock button right to the sliders, which are used for specifying the pyramid levels, you can select different pyramid levels for the model image and the model. When pressing the button again, both levels are locked again.
Detailed information about the model image pyramid can be found
(page
2 Specifying Standard Model Parameters
Via the menu item Create Model . Standard Model Parameters the tab Model Creation is opened and you can specify basic parameters for the model, which describe the appearance of the object to recognize, e.g., the contrast of significant points or the allowed range of rotation.
By default, these parameters are set to values which work well for most tasks; by modifying them you can optimize the model for your application and speed up the search process.
The following parameters can be specified in this dialog:
• the
which points must have in order to be included in the model,
• the
(page
• the number of
(page
194 ) on which the model is created,
• the
(page
195 ) of the allowed range of rotation,
• the allowed range of rotation (
(page
6.3.3 Matching Assistant Reference 193
• the
(page
In most applications, specifying the standard parameters will already suffice. Therefore, you can directly
(page
186 ) now. Additionally, advanced model parameters can be specified via the menu
item Create Model .
(page
2 The Model Parameter Contrast (Low/High)
The two parameters Contrast (Low) and Contrast (High) determine which pixels in the selected
(page
185 ) are included in the model
(page
185 ); typically, the points corresponding to the contours
of the object should be selected.
When you select a value, either by using the sliders or by entering a value in the text fields next to them, the included pixels are marked in the displayed image. In order to obtain a suitable model we recommend to choose the contrast in such a way that the significant pixels of the object are included, i.e., those pixels that characterize it and allow to discriminate it clearly from other objects or from the background. Please assure that no clutter is included, i.e., pixels that do not belong to the object!
You can use the parameters in two ways:
1. Simple threshold:
Set both parameters to the same value. Then, all pixels with a contrast higher than this value are included in the model.
You can modify both parameters at the same time as follows: To increase the value, use the slider of Contrast (Low); then, the value Contrast (High) will follow automatically. Vice versa, to decrease the value use the slider of Contrast (High).
2. Hysteresis threshold:
If there is no single contrast value that selects all significant object pixels without including clutter, try using different values for Contrast (Low) and Contrast (High). Then, pixels are selected in two steps: First pixels that have a contrast higher than Contrast (High) are selected; then, pixels that have a contrast higher than Contrast (Low) and that are connected to a high-contrast pixel, either directly or via another pixel with contrast above the lower threshold, are added.
We recommend to proceed as follows: Increase both values (using the slider of Contrast (Low)), until no clutter pixels are selected anymore. Then, decrease Contrast (Low) to add more object pixels. If significant object parts remain unselected, decrease Contrast (High).
Note that these parameters are used only to select model points in the model image. In the test images, the object may have a lower contrast.
You can also let the Matching Assistant
select suitable values automatically
based on the model image.
An additional method for removing clutter is to specify a
for the model components. If you cannot find suitable parameter values that exclude the clutter, we recommend to create a new model
ROI via the menu item Create Model .
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194 HDevelop Assistants
2 Letting the Matching Assistant Select a Suitable Value for Contrast
When you click the button Auto Select that is placed right beside the sliders for the parameters
the Matching Assistant selects suitable values for the contrast by trying to obtain many long and straight contour segments.
Note that you may need to set the value manually if certain model components should be included or suppressed because of application-specific reasons or if the object contains several different contrasts.
2 The Model Parameter Minimum Component Size
The parameter Min Component Size specifies the minimum size, i.e., number of pixels, which contour parts must have to be included in the
(page
185 ). This parameter is useful to exclude clutter.
You can also let the Matching Assistant
select a suitable value automatically
based on the
(page
Note that the selected value is divided by two for each successive pyramid level.
2 Letting the Matching Assistant Select a Suitable Value for Minimum Component Size
When you click the button Auto Select that is placed right beside the slider for the parameter
the Matching Assistant selects a suitable value for the minimum component size based on the model image.
2 The Model Parameter Pyramid Levels
To speed up the matching process, a so-called image pyramid is created, both for the model image and for the search images. The pyramid consists of the original, full-sized image and a set of downsampled images. For example, if the original image (first pyramid level) has the size 600x400, the second level image has the size 300x200, the third level 150x100, and so on. The object is then searched first on the highest pyramid level, i.e., in the smallest image. The results of this fast search are then used to limit the search in the next pyramid image, whose results are used on the next lower level until the lowest level is reached. Using this iterative method the search is both fast and accurate.
You can inspect the model image pyramid together with the corresponding models via the menu item
Create Model .
(page
191 ), which opens the corresponding dialog of the
tab Model Creation. We recommend to choose the highest pyramid level at which the model contains at least ten pixels (and still resembles the original shape). You can enter the value directly in the text field or by using the slider next to it. Alternatively, you can let the Matching Assistant
select a suitable value automatically .
Note that the Matching Assistant can check whether the model contains enough points on the selected number of pyramid levels only when actually creating the model. In case the model does not contain enough model points a corresponding error dialog appears.
2 Letting the Matching Assistant Select a Suitable Value for Pyramid Levels
When you click the button Auto Select that is placed right beside the slider for the parameter
the Matching Assistant selects a suitable number of pyramid levels automatically, thus relieving you of the task of examining the model image pyramid.
6.3.3 Matching Assistant Reference 195
Please note that in rare cases the automatic selection will yield a too low value and thereby slow down the search process, or a too high value, resulting in failures to recognize the object. In such a case we recommend to
inspect the model image pyramid
(page
191 ) and select a suitable value manually.
2 The Model Parameter Start Angle
With the parameter Start Angle you can specify the starting angle of the allowed range of rotation
(unit:°). With another parameter you can specify the
of the allowed range. Note that the range of rotation is defined relative to the model image, i.e., a starting angle of 0° corresponds to the orientation the object has in the model image. Therefore, to allow rotations up to +/-5°, e.g., you should set the starting angle to -5° and the angle extent to 10°.
2 The Model Parameter Angle Extent
With the parameter Angle Extent you can specify how much the object is allowed to rotate (unit:°).
With another parameter you can specify the
of this allowed range. Note that the range of rotation is defined relative to the model image, i.e., a starting angle of 0° corresponds to the orientation the object has in the model image. Therefore, to allow rotations up to +/-5°, e.g., you should set the starting angle to -5° and the angle extent to 10°.
We recommend to limit the allowed range of rotation as much as possible in order to speed up the search process and to minimize the required memory. If the
(page
in its extreme orientations, you can let the Matching Assistant determine the range of rotation, i.e., the
(page
207 ), by pressing the Run button of the tab Inspect and viewing the result in the
Statistics output of the same tab.
Furthermore, you must limit the allowed range if the object is (almost) symmetrical. Otherwise the search process will find multiple, almost equally good matches on the same object at different angles; which match (at which angle) is returned as the best can therefore "jump" from image to image. The suitable range of rotation depends on the symmetry: For a cross-shaped or square object the allowed extent must be less than 90°, for a rectangular object less than 180°, and for a circular object 0°.
Note that if you have chosen a very large angle and
you may find it useful to switch off the
(page
2 The Model Parameters for the Scale Range
The allowed range of scale is defined separately in row and column direction. Thus, it is described by the parameters:
• Minimum Row Scale
• Maximum Row Scale
• Minimum Column Scale
• Maximum Column Scale
In the model image, the scales all have the value 1.0.
196 HDevelop Assistants
Note that if you have chosen a very large
and scale range you may find it useful to switch off the
(page
Depending on the specified parameters, the most efficient matching method is used. This method determines how the shape model is created in the generated code.
• Unscaled matching:
This method is used if all four scale factors are equal to 1.0.
• Scale invariant matching:
This method is used if all four scale factors are equal (but not 1.0) or locked.
• Anisotropic scale invariant matching:
This method is used if none of the above applies.
2 Specifying Advanced Model Parameters
In most applications, specifying the
(page
The menu item Create Model . Advanced Model Parameters provides additional parameters that let you handle special cases like changing the contrast polarity or enable you to further optimize the model.
The following parameters can be specified in this dialog:
• the
at which the model is created,
• the
at which the model is created,
• whether to use the polarity of the contrast (
• whether to
(page
198 ) by using a reduced number of points,
• whether to
pregenerate the model completely
(page
• the
(page
198 ) points must have in a search image to be compared with the
model.
2 The Model Parameter Angle Step
The standard model parameters
(page
(page
much the object is allowed to rotate. To speed up the matching process the Matching Assistant precomputes instances of the model at intermediate angles in this range, at steps specified in the parameter
Angle Step.
Note that each time you create a model
(page
(page
the Matching Assistant automatically selects a suitable value to obtain the highest possible accuracy. You can select a higher value manually. This may be useful to speed up the search process in special cases; please note however, that a large value may decrease the accuracy of the estimated orientation and even prevent the Matching Assistant from finding the object! You can restore the automatically selected value by clicking the button
6.3.3 Matching Assistant Reference 197
If you already
(page
200 ) you can quickly test the effect of the selected parameter
value via the menu item Inspect .
(page
2 Letting the Matching Assistant Select a Suitable Value for Angle Step
When you click the button Auto Select that is placed right beside the slider for the parameter
the Matching Assistant selects a suitable value for the angle step size to obtain the highest possible accuracy.
2 The Model Parameters Row Scale Step and Column Scale Step
The standard model parameters for the
(page
195 ) specify how much the object is allowed
to be scaled in row and column direction. To speed up the matching process the Matching Assistant precomputes instances of the model at intermediate scales in this range, at steps specified in the parameters
Row Scale Step and Column Scale Step.
Note that each time you create a model
(page
(page
the Matching Assistant automatically selects a suitable value to obtain the highest possible accuracy. You can select a higher value manually. This may be useful to speed up the search process in special cases; please note however, that a large value may decrease the accuracy of the estimated orientation and even prevent the Matching Assistant from finding the object! You can restore the automatically selected value by clicking the button
If you already
(page
200 ) you can quickly test the effect of the selected parameter
value via the menu item Inspect .
(page
2 Letting the Matching Assistant Select a Suitable Value for Row Scale Step and Column Scale
Step
When you click the button Auto Select that is placed right beside the sliders for the parameters
the Matching Assistant selects suitable values for both scale step sizes based on the model image.
2 The Model Parameter Metric
The parameter Metric lets you choose whether the polarity of the contrast is to be observed when comparing a test image with the model. By default, the polarity is used (’use_polarity’), i.e., the points in the test image must show the same direction of the contrast as the corresponding points in the model.
You can choose to ignore the polarity globally (’ignore_global_polarity’), at the cost of a slightly lower recognition speed. In this mode, an object is recognized also if the direction of its contrast reverses, e.g., if your object can appear both as a dark shape on a light background and vice versa.
A third mode lets you ignore the polarity locally (’ignore_local_polarity’), i.e., objects are also recognized if the direction of the contrast changes only in some parts. This mode can be useful, e.g., if the object consists of a part with a medium gray value, within which either darker or brighter sub-objects lie.
Please note, however, that the recognition speed decreases dramatically in this mode, especially if you allowed a large
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198 HDevelop Assistants
Finally, you can choose to ignore the color polarity (’ignore_color_polarity’) to apply shape based matching to multi-channel images.
If you already
(page
200 ) you can quickly test the effect of the selected parameter
value via the menu item Inspect .
(page
2 The Model Parameter Optimization
After you created a model
(page
185 ), by default all points showing the required
(page
193 ) (and belonging to components larger than the
(page
(page
185 ) and marked in the image. For particularly large models, i.e., a large number of model points,
it might be useful to reduce the number of points using the parameter Optimization in order to speed up the
(page
185 ) process and to reduce memory requirements. You can select a low, medium, or
high point reduction; please note that regardless of your selection all points passing the contrast criterion are displayed, i.e., you cannot check which points are part of the model.
You can also let the Matching Assistant
select a suitable value automatically
based on the model image.
Another possibility to reduce the memory requirements of the model is to switch off the
of the model.
If you already
(page
200 ) you can quickly test the effect of the selected parameter
value via the menu item Inspect .
(page
2 Letting the Matching Assistant Select a Suitable Value for Optimization
When you click the button Auto Select that is placed right beside the slider for the parameter
the Matching Assistant optimizes, i.e., reduces the number of model points based on the model image.
2 The Model Parameter Pregenerate Shape Model
The parameter Pregenerate Shape Model specifies whether the internal representation of the shape model is pregenerated completely whenever the model is created.
If you select a complete pregeneration by checking the check box Pregenerate Shape Model the model generation may require a substantial amount of time and memory. In contrast, if you switch off the complete pregeneration, the model creation will be very fast and the model will consume less memory.
The advantage of selecting a complete pregeneration is that the model can typically be found slightly faster than if the complete pregeneration is switched off. Typically, you may find it useful to switch off the complete pregeneration if your model uses a large angle and scale range.
2 The Model Parameter Minimum Contrast
In order to select significant object points for the
(page
(page
193 ) the points must show in the
(page
185 ). With the parameter Minimum Contrast you
can specify a separate minimum contrast for the
(page
185 ) process itself, i.e., when searching
6.3.3 Matching Assistant Reference 199
for the object in the
(page
185 ). The main use of this parameter is to exclude noise, i.e., gray
value fluctuations, from the matching process.
Note that a low value for Minimum Contrast slows down the matching process because more points in the test image must be compared with the model. Therefore, we recommend to choose a value which is higher than the noise in the test images. You can also let the Matching Assistant
select a suitable value automatically
based on the model image.
Note that although this parameter is only used during the search, it is already included when creating the model in order to speed up the matching process.
If you already
you can quickly test the effect of the selected parameter value via the menu item Inspect .
(page
2 Letting the Matching Assistant Select a Suitable Value for Minimum Contrast
When you click the button Auto Select that is placed right beside the slider for the parameter
(page
198 ) the Matching Assistant selects a suitable value for the minimum contrast by eval-
uating the gray value fluctuations, i.e., the noise in the model image.
Note that an automatic determination only makes sense if the image noise during the recognition is similar to the noise in the model image. For this reason, it is typically not useful when using a synthetic model image (without noise).
2 Reset All Parameters
The button Reset inside the tab Model Creation resets all model and search parameters to their default settings and deletes the
(page
(page
(page
6.3.3.3
The Menu Use Model and the Tab Model Use
Via the menu Use Model as well as the tab Model Use you can
•
•
delete a selected test image ,
•
at once,
•
display the selected test image
(page
• access the
in the tab Model Use,
• open the dialog for the
(page
203 ) and advanced search parameters
(page
• open the dialog for the
optimization of the recognition speed
(page
• directly start to
optimize the recognition speed
(page
200 HDevelop Assistants
In the tab Model Use you can additionally
•
• specify the number of
(page
• start the matching for a
or
• for the whole
2 Loading Test Images
The so-called
(page
185 ) should be representative images from your matching application,
i.e., the object should appear in all allowed variations of its position, orientation, occlusion, and illumination.
When you select the menu item Use Model . Test Images . Load Test Images (or click the corresponding button Load in the tab Model Use), a standard file selection box appears, in which you can select one or more images to load. The Matching Assistant can read the image file types TIFF, BMP,
GIF, JPEG, PPM, PGM, PNG, and PBM. Please note that the test images must have the same size as the model image!
A dialog appears in the tab Model Use which enables you to
on the loaded images.
2 Deleting a Test Image
When you select the menu item Use Model . Test Images . Delete Test Image or click the button Delete inside the dialog Test Images of the tab Model Use, the currently selected test image is deleted from the list of test images. You can
by clicking onto its index number or path in the text field left to the buttons.
You can also
test images at once.
2 Deleting All Test Images
When you select the menu item Use Model . Test Images . Delete All Test Images or click the button Delete All in the dialog Test Images of the tab Model Use, all test images are deleted from the list of test images.
You can also
delete a selected test image .
2 Test Images
With the menu item Use Model . Test Images you can
•
test images,
•
a selected test image or
test images,
•
display an already selected test image , and
• open the dialog Test Images inside the tab Model Use
6.3.3 Matching Assistant Reference 201
The dialog Test Images inside the tab Model Use you need to additionally
•
for display or deletion,
• specify the
for each image, and
• search for the model in the
complete sequence of test images , in the currently selected test image ,
or
automatically after each selection .
2 Searching for the Object in a Test Image
When you click the button Find Model in the dialog Test Images of the tab Model Use the object is searched for in the currently
test image; the result is displayed in the graphics window.
Please note that if the button is clicked for the first time or after you changed a model parameter, the internally stored model is actually created, which takes some time. If the model creation takes a long time (i.e., if you have chosen a very large
(page
(page
useful to switch off the
(page
You can also search for the object in the whole
of test images at once.
2 Searching for the Object in All Test Images
When you click the button Detect All inside the dialog Test Images of the tab Model Use, the object is searched for in the complete sequence of test images that were
(page
results are displayed successively in the graphics window.
Please note that if the button is clicked for the first time or after you changed a model parameter, the internally stored model is actually created, which takes some time. If the model creation takes a long time (i.e., if you have chosen a very large
(page
(page
useful to switch off the
(page
You can also search for the object in a
test image.
2 Automatically Searching for the Object in the Test Images
If you check the box Always Find in the dialog Test Images of the tab Model Use (also accessible via the menu item Use Model . Test Images . Show Test Image Settings), the object is searched for automatically whenever you select a new test image.
Please note that if the matching process is started for the first time or after you changed a model parameter, the internally stored model is created, which takes some time. If the model creation takes a long time (i.e., if you have chosen a very large angle and scale range), you may find it useful to switch off the
(page
2 Selecting and Displaying a Test Image
You can select a test image by clicking with the left mouse button onto its number (index) or path in the text box of the dialog Test Images of the tab Model Use. The selected image is automatically displayed in the graphics window of HDevelop.
202 HDevelop Assistants
If the checkbox labelled
is checked, the matching process is started automatically on the selected test image; its result is displayed in the graphics window.
If you want to redisplay the selected test image in a later step, e.g., after you
(page
191 ) again, you can also display it via the menu item Use Model . Test Images . Display
Selected Test Image without newly selecting it.
2 Specifying the Number of Objects Visible in a Test Image
In the dialog
(page
200 ) in the tab Model Use, you can specify how many objects are
visible in the current test image using the corresponding text box that appears when clicking onto the currently displayed number of visible objects in the text field of the currently selected test image. The default value is 1.
If you select the corresponding recognition mode in the dialog accessed via Use Model .
(page
206 ), the specified numbers of visible objects are used when
determining the recognition rate, i.e., the recognition rate is 100% when the sum of all objects found in the test images is equal to the sum of the specified numbers.
2 Assuring the Matching Success
After
(page
200 ) the test images you can quickly test whether all objects are found successfully
via the dialog Inspect .
(page
207 ). If the matching succeeds in all
test images, i.e., if a recognition rate of 100% is reached, you can start to
(page
of the matching process.
If the matching fails in one or more test images, proceed as follows:
• Open the dialog
(page
• Check the box
(page
•
(page
201 ) to determine the images where the matching fails.
• If an object is not found check whether one of the following situations causes your problem:
• Is the object crossing the image border, i.e., does it lie partially outside the test image?
By default the objects must lie completely within the test image in order to be found. This behavior can be changed in the dialog
(page
tab Model Use via the parameter
Shape models may cross the image border
(page
• Is the Matching Assistant too greedy ?
By default, the Matching Assistant uses a fast search heuristic which might overlook an object. Therefore, try reducing the corresponding parameter
(page
dialog
(page
204 ) manually or automatically via the
menu item Inspect .
(page
• Is the object partly occluded?
If the object is to be recognized in this state nevertheless, try reducing the parameter
in the dialog
in the tab Model Use manually or automatically via the menu item Inspect .
(page
6.3.3 Matching Assistant Reference 203
• Has the object a low contrast?
If the object is to be recognized in this state nevertheless, try reducing the parameter
(page
(page
Model Creation.
• Do multiple objects overlap?
If the objects are to be recognized in this state nevertheless, try decreasing the
in the dialog
in the tab Model Use.
• If the object is found but not at the expected position or orientation check the following:
• If multiple matches are found on one and the same object, decrease the
in the dialog
• If an almost symmetric object is found at the wrong orientation try reducing the parameters specifying the
(page
(page
192 ) in the tab Model Creation.
2 Specifying Standard Model Use Parameters
Via the menu item Use Model . Standard Model Use Parameters, you can specify
• the
the object must have and
• the number of instances of the object that are searched for in an image (
Additionally, advanced search parameters can be specified via the menu item Use Model .
2 The Search Parameter Minimum Score
When comparing a region in a test image with the
(page
185 ), the Matching Assistant calculates
a measure of similarity, the so-called
(page
185 ), which ranges between 0 (no similarity) and 1
(perfect similarity). With the parameter Minimum Score you can specify a minimum score that a match must reach.
Graphically speaking, the parameter specifies how much of the object, i.e., of the model points, must be visible. A part of the object may be invisible not only because it is occluded, but also if its contrast is lower than the selected
(page
198 ) or has the wrong polarity
(page
further cause of invisibility could be a (too) large
(page
The larger the value is chosen, the faster the search is, because candidate matches can be discarded earlier. Therefore, this parameter can be optimized easily: Starting from the maximum value, reduce the value until the object is found in all
(page
185 ); in fact, this method is used by the Matching
Assistant itself when you start the optimization via the menu item Inspect .
(page
Choosing small values may cause the program to search for quite a while. In such a case we recommend to enter a larger value in the text box instead of using the slider.
204 HDevelop Assistants
Please note that by default the objects must lie completely within the test images in order to be found.
This behavior can be changed via the parameter
Shape models may cross the image border
(page
205 ) in the dialog accessed via the menu item Use Model .
2 The Search Parameter Maximum Number of Matches
The parameter Maximum Number of Matches specifies how many instances of the object are searched for in the image. Note that the parameter sets a maximum value, i.e., if more object instances are present in the image only the best instances of the specified number are displayed. If you specify the value 0, all found instances are displayed.
2 Specifying Advanced Model Use Parameters
Via the menu item Use Model . Advanced Model Use Parameters, you can specify:
• the
of the search algorithm,
• how much the objects may overlap (
) of the calculated position, orientation, and scale,
• the lowest pyramid level
to which the found matches are tracked, and
• whether objects that lie partially outside the image (
Shape model may cross the image border
2 The Search Parameter Greediness
The parameter Greediness influences the search algorithm used by the Matching Assistant. It ranges between 0 and 1. If you select a low value, the search is thorough but relatively slow. The higher the value, the faster the search algorithm becomes, but at the cost of thoroughness, i.e., an object might not be found even though it is visible in the image.
This parameter can be optimized easily: Starting from the value 0, increase the value until the matching fails in a test image, and then use the last value for which the object is found; in fact, this method is used by the Matching Assistant itself when you start the optimization via the menu item Use Model .
(page
2 The Search Parameter Maximum Overlap
The parameter Maximum Overlap specifies how much two matches may overlap in the image; its value ranges between 0 and 1. Especially in the case of an almost symmetric object the allowed overlap should be reduced to prevent multiple matches on the same object.
2 The Search Parameter Subpixel
The parameter Subpixel allows to select the accuracy with which the position, orientation, and scale are calculated. If you select the value ’none’, the position is determined only with pixel accuracy, and
6.3.3 Matching Assistant Reference 205
the accuracy of the orientation and scale is equal to the
(page
(page
If you select the value ’interpolation’, the Matching Assistant examines the matching scores at the neighboring positions, angles, and scales around the best match and determines the maximum by interpolation.
Using this method, the position is therefore estimated with sub-pixel accuracy. The accuracy of the estimated orientation and scale depends on the size of the object: The larger the size, the more accurately the orientation and scale can be determined. For example, if the maximum distance between the center and the boundary is 100 pixel, the orientation is determined with an accuracy of about 0.1°.
Because the interpolation is very fast, you can select ’interpolation’ in most applications.
When you choose the values ’least_squares’, ’least_squares_high’, or ’least_squares_very_high’, a leastsquares approximation is used instead of an interpolation, resulting in an even higher accuracy. However, this method requires additional computation time.
2 The Search Parameter Last Pyramid Level
With the parameter Last Pyramid Level you can select the lowest pyramid level to which the found matches are tracked. For example, when selecting the value 2, the matching starts at the highest pyramid level and tracks the matches to the second lowest pyramid level (the lowest pyramid level is denoted by a value of 1).
This mechanism can be used to speed up the matching. It should be noted, however, that in general the accuracy of the extracted position, orientation, and scale is lower in this mode than in the normal mode, in which the matches are tracked to the lowest pyramid level. Hence, if a high accuracy is desired, the parameter
(page
204 ) should be set to at least ’least_squares’.
Note that if the lowest pyramid level to use is chosen too large, it may happen that the desired accuracy cannot be achieved, or that wrong instances of the model are found because the model is not specific enough on the higher pyramid levels to facilitate a reliable selection of the correct instance of the model.
In this case, the lowest pyramid level to use must be set to a smaller value.
2 The Search Parameter Shape models may cross the image border
With the parameter Shape models my cross the image border you can specify whether shape models that cross the image border, i.e., that lie partially outside the test images, should be searched.
If you switch off the check box Shape models may cross the image border the shape model will only be searched within those parts of the test images in which the shape model completely lies within the image.
If you switch on the check box Shape models may cross the image border the shape model will be searched for in all positions in which the model additionally lies partially outside the test images, i.e., in which the shape model extends beyond the image border. Here, points lying outside the image are regarded as being occluded, i.e., they lower the score. This should be taken into account while selecting the
(page
203 ). Please note that the runtime of the search will increase in this mode.
206 HDevelop Assistants
2 Optimizing the Recognition Speed
When you select the menu item Use Model . Optimize Recognition Speed or click either the corresponding button in the tool bar or the button Run Optimization in the dialog Optimize Recognition
Speed of the tab Model Use, the Matching Assistant automatically determines values for the parameters
(page
(page
204 ) to optimize the recognition speed. The speed
is calculated as the average recognition speed over all test images. You can interrupt this process by clicking the button labelled Stop; please note however, that this event is processed only after the current search has finished.
The two parameters are optimized as follows: At the beginning, the greediness is set to 0 and the minimum score to 1. Then, the minimum score is decreased until the matching succeeds in all test images, i.e., until the recognition rate is 100%. Now, the greediness is increased as long as the matching succeeds. This process is repeated until the optimum parameters are found. You can lower the threshold of acceptance for the recognition rate manually using the corresponding slider or text box at the bottom of the dialog.
The Matching Assistant then displays the optimal minimum score and greediness and the reached recognition time. It automatically enters the parameter values in the dialogs Use Model .
(page
(page
spectively.
If a test image can contain more than one object, the term ’recognition rate’ is ambiguous. Therefore, you can choose between three recognition modes:
• In each test image, at least one object is expected. The recognition rate is calculated as the percentage of test images which fulfill this condition, i.e., it is 100% if in all test images at least one object is found.
• In each test image, as many objects are expected as specified in the parameter
(page
204 ) in the dialog accessed via Use Model .
(page
203 ). The recognition rate is calculated as the relation of found objects to the
sum of expected objects over all images, i.e., it is 100% if in all test images (at least) Maximum
Number of Matches objects are found.
• In each test image, as many objects are expected as
(page
(page
200 ) of the tab Model Use. The recognition rate is calculated as the relation
of found objects to the sum of expected objects over all images, i.e., it is 100% if in each image exactly as many objects are found as specified.
Note that if you select Maximum Number of Matches = 0 and by mistake specify a lower number of visible objects than actually present in a test image, a recognition rate . 100% results, which completely confuses the optimization algorithm. You may handle this case by selecting the condition . = 100% for the recognition rate.
6.3.3.4
The Menu and Tab Inspect
Via the menu Inspect you can
determine the recognition rate
and the
of the object for the used set of test images. Besides the automatical determination of the recognition rate, the tab Inspect is opened. Alternatively, you can directly open the tab and select the button Run. Inside the tab, you can
6.3.3 Matching Assistant Reference 207
also specify the
(page
204 ) of object instances the Matching Assistant should search
for.
2 Determining the Recognition Rate
With the menu item Inspect . Determine Recognition Rate or when you click either the corresponding button in the tool bar or the button Run in the tab Inspect, the Matching Assistant determines the recognition rate by searching the object in all loaded test images. You can interrupt this process by clicking the button labelled Stop; please note however, that this event is processed only after the current search has finished.
The Matching Assistant then displays at Recognition Rate the recognition rate calculated for different criteria and at Statistics the mean, minimum, and maximum
(page
minimum, and maximum matching time.
You can choose between three recognition modes:
• In each test image, at least one object is expected. The recognition rate is calculated as the percentage of test images which fulfill this condition.
• In each test image, as many objects are expected as specified in the parameter
(page
204 ) in the dialog accessed via Use Model .
(page
203 ). The recognition rate is calculated as the relation of found objects to the
sum of expected objects over all images (in percent).
Please keep in mind that if an image contains more objects than specified in the parameter Maximum
Number of Matches, only the best Maximum Number of Matches instances are found! Therefore, if there are, e.g., two test images containing 1 and 3 objects, respectively, and you select
Maximum Number of Matches = 2, the recognition rate will be 75%, i.e., 3 out of 4 expected objects.
• In each test image, as many objects are expected as
(page
accessed via Use Model .
(page
is calculated as the relation of found objects to the sum of expected objects over all images (in percent).
Before using this mode, please check the value specified for the parameter
(page
204 ): If it is not set to 0, it should not be smaller than the maximum number of
objects visible in a test image; otherwise, the recognition rate will be below 100%.
Note that if you select Maximum Number of Matches = 0 and by mistake specify a lower number of visible objects than actually present in a test image, a recognition rate . 100% results. To further extend this line of thought: If for some reason in another test image an object is not found, the two errors cancel each other out, i.e., the recognition rate is 100%! Therefore, we recommend to check whether the correct objects are found via the dialog
(page
Model Use.
2 Determining the Pose Bounds
When you click the button Run in the tab Inspect, besides the
the Matching Assistant determines so-called pose bounds, i.e., the range of positions, orientations, and scales in which the object
208 HDevelop Assistants
appears in the test images. You can interrupt this process by clicking the button labelled Stop; please note however, that this event is processed only after the current search has finished.
If the test images cover the whole ranges of allowed orientations and scales of the object you can use the calculated ranges to optimize the parameters
(page
(page
the parameters for the
(page
195 ) in the dialog accessed via the menu item Create Model .
(page
192 ); we recommend to use slightly larger values to get accurate
results at the boundaries of the ranges.
In a corresponding HALCON program you can use the calculated range of positions as a region of interest and thus further speed up the matching process.
6.3.3.5
The Menu and Tab Code Generation
Via the menu Code Generation you can
• open the dialog
inside the tab Code Generation, where options for the code generation can be set,
• open the dialog
inside the tab Code Generation, where the names for the used variables can be specified,
•
to the program window of HDevelop according to the current settings of the Matching
Assistant,
•
release the generated code lines
in the program window,
•
delete the generated code lines
from the program window as long as you did not released them, and
• open the dialog for the
inside the tab Code Generation.
2 Specifying the Options for the Code Generation
Via the menu item Code Generation . Show Code Generation Options you can open the dialog for determining the options for the code generation inside the tab Code Generation. The dialog consists of the following parts:
• radio buttons for selecting whether the shape model is created at run time from the
(page
185 ) or if an already existing shape model is to be loaded. For the first case, you can
additionally select whether to use the model image and the
(page
inside the Matching Assistant or whether a new ROI has to be drawn at run time,
• a check box to select whether to display the detected model instances in a loop, and
• the button
to insert the code generated by the Matching Assistant into the program window of HDevelop.
6.3.3 Matching Assistant Reference
2 Specifying the Variables for the Code Generation
Via the menu item Code Generation . Show Variables for Code Generation you can open the dialog for determining the variables used for the code generation inside the tab Code Generation. The dialog consists of several text fields for the individual variables needed for the code lines. The Matching
Assistant automatically generates reasonable variable names, but you can change the individual names via the text fields.
2 Insert the Generated Code Lines
Via the menu item Code Generation . Insert Code (also accessible as tool bar button or as button inside the tab Code Generation), you can insert the code that is generated according to the current settings of the Matching Assistant into the program window.
2 Release the Generated Code Lines
Via the menu item Code Generation . Release Generated Code Lines you can release the generated and inserted code lines. After releasing the code lines, all connections between the Matching
Assistant and the program window of HDevelop are lost. That is, changes, e.g., the deletion of code lines, can then only be applied directly in the program window and not from within the Matching Assistant anymore.
2 Delete the Generated Code Lines
Via the menu item Code Generation . Delete Generated Code Lines you can delete the code lines that you have previously generated and
into the program window of HDevelop from within the Matching Assistant. Note that this works only as long as you have not yet
the code lines.
2 Preview of the Generated Code Lines
Via the menu item Code Generation . Show Code Preview you can open the dialog for the Code
Preview in the tab Code Generation. Here, you have the possibility to, e.g., edit or replace individual operators of the code lines proposed by the Matching Assistant.
6.3.3.6
The Menu Help
Via the menu Help you can access the online documentation.
209
210 HDevelop Assistants
HDevelop Language 211
Chapter 7
HDevelop Language
This chapter introduces the syntax and the semantics of the HDevelop language. In other words, it illustrates what you can enter into a parameter slot of an operator or procedure call. In the simplest case this is the name of a variable, but it might also be an arbitrary expression like sqrt(A). Besides, control structures (like loops) and the semantics of parameter passing are described.
Note that the HALCON operators themselves are not described in this chapter. For this purpose refer to the HALCON reference manual. All program examples used in this chapter can also be found in the directory %HALCONROOT%\examples\hdevelop\Manuals\HDevelop.
7.1
Basic Types of Parameters
HALCON distinguishes two kinds of data: control data (numbers or strings) and iconic data (images, regions, etc.)
By further distinguishing input from output parameters, we get four different kinds of parameters. These four kinds always appear in the same order in the HDevelop parameter list. In the reference manual operator signatures are visualized in the following way: operator ( iconic input : iconic output : control input : control output )
As you see, iconic input objects are always passed first, followed by the iconic output objects. The iconic data is followed by the control data, and again, the input parameters succeed the output parameters.
Any of the four types of parameters may be empty. For example, the signature of read_image reads read_image ( : Image : FileName : )
The operator read_image has one output parameter for iconic objects
Image and one input control parameter
FileName
. The parameter types are reflected when entering operators in the operator window.
The actual operator call displayed in the HDevelop program window is:
212 HDevelop Language
read_image (Image,
'Name')
The parameters are separated by commas. Input control parameters can either be variables, constants or expressions. An expression is evaluated before it is passed to a parameter that receives the result of the evaluation. Iconic parameters must be variables. Control output parameters must be variables, too, as they store the results of an operator evaluation.
7.2
Control Types and Constants
All non-iconic data is represented by so called control data (numbers or strings) in HDevelop. The name is derived from their respective functions within HALCON operators where they control the behaviour
(the effect) of image processing (e.g., thresholds for a segmentation operator). Control parameters in
HDevelop may contain arithmetic or logical operations. A control data item can be of one of the following types: integer, real, string, and boolean.
integer and real The types integer and real are used under the same syntactical rules as in C.
Integer numbers can be input in the standard decimal notation, in hexadecimal by prefixing the number with 0x, and in octal by prefixing the number with 0. For example:
4711
-123
0xfeb12
073421
73.815
0.32214
.56
-17.32e-122
32E19
Data items of type integer or real are converted to their machine-internal representations: real becomes the C-type double (8 bytes) and integer becomes the C-type long (4 or 8 bytes).
string A string is a sequence of characters that is enclosed in single quotes (’). The maximum string length is limited to 1024 characters. Special characters, like the line feed, are represented in the
C-like notation, as you can see in
(see the reference of the C language for comparison).
You can enter arbitrary characters using the format \xnn where nn is a two-digit hexadecimal number, or using the format \0nnn where nnn is a three-digit octal number. Less digits may be used if the string is unambiguous. For example, a line feed may be specified as \xa unless the string continues with another hexadecimal digit (0-F).
For example: The string Sobel’s edge-filter has to be specified as ’Sobel\’s edge-filter’.
A Windows directory path can be entered as ’C:\\Programs\\MVTec\\
Halcon\\images’ boolean The constants true and false belong to the type boolean. The value true is internally represented by the number 1 and the value false by 0. This means, that in the expression Val
7.2 Control Types and Constants 213
Meaning line feed horizontal tabulator vertical tabulator backspace carriage return form feed bell backslash single quote arbitrary character (hexadecimal) arbitrary character (octal)
Abbreviation Notation
NL (LF) \n
\
’
HT
VT
BS
CR
FF
BEL
\t
\v
\b
\r
\f
\a
\\
\’
\xnn
\0nnn
Table 7.1: Surrogates for special characters.
:= true the effective value of Val is set to 1. In general, every integer value other than 0 means true. Please note that some HALCON operators take logical values for input (e.g., set_system
).
In this case the HALCON operators expect string constants like ’true’ or ’false’ rather than the boolean values true or false.
In addition to these general types, there are special constants and the type tuple, which are specific to
HALCON or HDevelop, respectively.
constants There are constants for the return value (result state) of an operator. The constants can be used together with the operator dev_error_var and dev_set_check
. These constants represent the normal return value of an operator, so called messages. For errors no constants are available (there are more than 400 error numbers internally, see the Extension Package Programmer’s Manual).
In
all return messages can be found.
tuple The control types are only used within the generic HDevelop type tuple. A tuple of length 1 is interpreted as an atomic value. A tuple may consist of several numerical data items with different
Constant Meaning Value
H_MSG_TRUE
No error; for tests: (true)
H_MSG_FALSE
For tests: false
H_MSG_VOID
No result could be computed 4
2
3
H_MSG_FAIL
Operator did not succeed 5
Table 7.2: Return values for operators.
214 HDevelop Language
Tuple constant Value
[
Value
Value
] string integer real boolean
,
Figure 7.1: The syntax of tuple constants.
types. The standard representation of a tuple is a listing of its elements included into brackets.
This is illustrated in
[] specifies the empty tuple. A tuple with just one element is to be considered as a special case, because it can either be specified in the tuple notation or as an atomic value: [55] defines the same constant as 55. Examples for tuples are:
[]
4711
0.815
'Text'
[16]
[100.0,100.0,200.0,200.0]
[
'FileName','Extension']
[4711,0.815,
'Hugo']
7.3
Variables
Names of variables are built up as usual by composing letters, digits and the underscore ‘_’. The maximum length of a variable name is limited to 256 characters. The kind of a variable (iconic or control variable) depends on its position in the parameter list in which the variable identifier is used for the first time (see also
on page
211 ). The kind of the variable is determined during the input of the
operator parameters: whenever a new identifier appears, a new variable with the same identifier is created. Control and iconic variables must have different names. The value of a variable (iconic or control) is undefined until the first assignment defines it (the variable has not been instantiated yet). A read access to an undefined variable leads to a runtime error (Variable <x> not instantiated).
HDevelop provides a pre-defined variable named _ (single underscore). You can use this variable for output control parameters whose value you are not interested in. Please note that it is not allowed to use this variable for HDevelop-specific operators (chapters Control and Develop in the HALCON
7.4 Operations on Iconic Objects 215
reference manual). It is not recommended to use the variable _ in programs that will later be exported to a foreign programming language.
Instantiated variables contain tuples of values. Depending on the kind of the variable, the data items are either iconic objects or control data. The length of the tuple is determined dynamically by the performed operation. A variable can get new values any number of times, but once a value has been assigned the variable will always keep being instantiated, unless you select the menu item Menu Execute . Reset
Program Execution. The content of the variable is deleted before the variable is assigned new values.
The concept of different kinds of variables allows a first (“coarse”) typification of variables (control or iconic data), whereas the actual type of the data (e.g., real, integer, string, etc.) is undefined until the variable gets assigned with a concrete value. Therefore, it is possible that the type of a new data item differs from that of the old.
7.4
Operations on Iconic Objects
Iconic objects are exclusively processed by HALCON operators. HALCON operators work on tuples of iconic objects, which are represented by their surrogates in the HALCON data management. The results of those operators are again tuples of iconic objects or control data elements. For a detailed description of the HALCON operators refer to the HALCON reference manual and the remarks in
on page
7.5
Expressions for Input Control Parameters
In HDevelop, the use of expressions like arithmetic operations or string operations is limited to control input parameters; all other kinds of parameters must be assigned by variables.
7.5.1
General Features of Tuple Operations
This section intends to give you a short overview over the features of tuples and their operations. A more detailed description of each operator mentioned here is given in the following sections.
Please note that in all following tables variables and constants have been substituted by letters which indicate allowed data types. These letters provide information about possible limitations of the areas of definition. The letters and their meaning are listed in
. Operations on these symbols can only be
applied to parameters of the indicated type or to expressions that return a result of the indicated type.
The symbol names i, a, l, and s can denote atomic tuples (tuples of length 1) as well as tuples with arbitrary length.
Operations are normally described assuming atomic tuples. If the tuple contains more than one element, most operators work as follows:
• If one of the tuples is of length one, all elements of the other tuples are combined with that single value for the chosen operation.
216 HDevelop Language
Symbol Types i a b s v t integer arithmetic, that is: integer or real boolean string all types (atomic) all types (tuple)
Table 7.3: Symbols for the operation description.
Input
5 * 5
[5] * [5]
[1,2,3] * 2
Result
25
25
[2,4,6]
[1,2,3] * 2.1 + 10 [12.1,14.2,16.3]
[1,2,3] * [1,2,3] [1,4,9]
[1,2,3] * [1,2] runtime error
’Text1’ + ’Text2’ ’Text1Text2’
17 + ’3’ ’173’
’Text ’ + 3.1 * 2 ’Text 6.2’
3.1 * (2 + ’Text’) runtime error
3.1 + 2 + ’ Text’ ’5.1 Text’
3.1 + (2 + ’Text’) ’3.12 Text’
Table 7.4: Examples for arithmetic operations with tuples and strings.
• If both tuples have a length greater than one, both tuples must have the same length (otherwise a runtime error occurs). In this case, the selected operation is applied to all elements with the same index. The length of the resulting tuples is identical to the length of the input tuples.
• If one of the tuples is of length 0 ([]), a runtime error occurs.
In
you can find some examples for arithmetic operations with tuples. Pay special attention to the order in which the string concatenations are performed. The basic arithmetic operations in HDevelop are +, -, *, /. Please note that + is a dimorphic operation: If both operands are numeric, it adds numbers.
If at least one of the operands is a string, it concatenates both operands as strings.
7.5.2 Assignment
7.5.2
Assignment
In HDevelop, an assignment is treated like an operator. To use an assignment you have to select the operator assign (Input, Result). This operator has the following semantics: It evaluates Input
(right side of assignment) and stores it in Result (left side of assignment). However, in the program text the assignment is represented by the usual syntax of the assignment operator: Result := Input.
The following example outlines the difference between an assignment in C syntax and its transformed version in HDevelop:
The assignment in C syntax u = sin(x) + cos(y); is defined in HDevelop using the assignment operator as assign(sin(x) + cos(y), u) which is displayed in the program window as: u := sin(x) + cos(y)
If the result of the expression does not need to be stored into a variable, the expression can directly be used as input value for any operator. Therefore, an assignment is necessary only if the value has to be used several times or if the variable has to be initialized (e.g., for a loop).
A second assignment operator is available: insert (Input, Value, Index, Result). It is used to assign tuple elements. If the first input parameter and the first output parameter are identical, the call: insert (Areas, Area, Radius-1, Areas) is not presented in the program text as an operator call, but in the more intuitive form as:
Areas[Radius-1] := Area.
As an example: assign([1,2,3], Area) assign(9, Areas) insert(Areas, Area, 1, Areas) sets Areas to [1,9,3].
To construct a tuple with insert
, normally an empty tuple is used as initial value and the elements are inserted in a loop:
217
218 HDevelop Language
Tuple := [] for i := 0 to 5 by 1
Tuple[i] := sqrt(real(i)) endfor
As you can see from the examples, the indices of a tuple start at 0.
An insertion into a tuple can generally be performed in one of the following ways:
1. In case of appending the value at the ‘back’ or at the ‘front’, the tuple concatenation operation ,
(comma) can be used. Here the operator assign is used with the following parameters: assign([Tuple,NewVal],Tuple) which is displayed as
Tuple := [Tuple,NewVal]
2. If the index position is somewhere in between, the operator insert has to be used. It takes the following arguments as input: first the tuple in which the new value should be inserted; then the new value and after that the index position as the third input parameter. The result (the fourth parameter) is almost identical with the input tuple, except of the new value at the defined index position (see the example above).
In the following example regions are dilated with a circle mask and afterwards the areas are stored into the tuple Areas. In this case the operator insert is used.
read_image (Mreut,
'mreut') threshold (Mreut, Region, 190, 255)
Areas := [] for Radius := 1 to 50 by 1 dilation_circle (Region, RegionDilation, Radius) area_center (RegionDilation, Area, Row, Column)
Areas[Radius-1] := Area endfor
Please note that first the variable Areas has to be initialized in order to avoid a runtime error. In the example Areas is initialized with the empty tuple ([]). Instead of insert the operator assign with tuple concatenation
Areas := [Areas,Area] could be used, because the element is appended at the back of the tuple. More examples can be found in the program assign.dev.
7.5.3 Basic Tuple Operations 219
Operation t := [t1,t2]
Meaning concatenate tuples i := |t| v := t[i] t := t[i1:i2] get number of elements of tuple t select element i of tuple t; 0
<= i < |t| select from element i1 to element i2 of tuple t t := subset(t,i) select elements specified in i from t t := remove(t,i) remove elements specified in i from t i := find(t1,t2) get indices of all occurrences of t2 within t1 (or -1 if no match) t := uniq(t) discard all but one of successive identical elements from t
HALCON operator tuple_concat tuple_length tuple_select tuple_select_range tuple_select tuple_remove tuple_find tuple_uniq
Table 7.5: Basic operations on tuples (control data) and the corresponding HALCON operators.
7.5.3
Basic Tuple Operations
A basic tuple operation may be selecting one or more values, combining tuples (concatenation) or getting the number of elements (see
for operations on tuples containing control data).
The concatenation accepts one or more variables or constants as input. They are all listed between the brackets, separated by commas. The result again is a tuple. Please note the following: [[t]] = [t] = t.
|t| returns the number of elements of a tuple. The indices of elements range from zero to the number of elements minus one (i.e., |t|-1). Therefore, the selection index has to be within this range.
Tuple := [V1,V2,V3,V4] for i := 0 to |Tuple|-1 by 1 fwrite_string (FileHandle,Tuple[i]+
'\n') endfor
In the following examples the variable Var contains [2,2,3,’a’,’a’,2,3,’b’,’b’]:
1
Please note that the index of objects (e.g., select_obj
) ranges from 1 to the number of elements.
220 HDevelop Language
control
[] iconic gen_empty_obj ()
[t1,t2] concat_obj (p1, p2, q)
|t| count_obj (p, num) t[i] select_obj (p, q, i+1) t[i1:i2] copy_obj (p, q, i1+1, i2-i1+1)
Table 7.6: Equivalent tuple operations for control and iconic data.
[3,Var,[8,9]]
|Var|
Var[4]
Var[4:6]
[3,2,2,3,’a’,’a’,2,3,’b’,b’,8,9]
9
’a’
[’a’,2,3] subset(Var,[3,6,7]) [’a’,3,’b’] remove(Var,[3,6,7]) [2,2,3,’a’,2,’b’] find(Var,[2,3]) uniq(Var)
[1,5]
[2,3,’a’,2,3,’b’]
Further examples can be found in the program tuple.dev. The HALCON operators that correspond to the basic tuple operations are listed in
on page
Note that these direct operations cannot be used for iconic tuples, i.e., iconic objects cannot be selected from a tuple using [] and their number cannot be directly determined using ||. For this purpose, however, HALCON operators are offered that carry out the equivalent tasks. In
you can see tuple operations that work on control data (and which are applied via assign or insert
) and their counterparts that work on iconic data (and which are independent operators). In the table the symbol t represents a control tuple, and the symbols p and q represent iconic tuples.
7.5.4
Tuple Creation
The simplest way to create a tuple, as mentioned in
on page
together with the operator assign
(or in case of iconic data one of its equivalents shown in
assign ([],empty_tuple) assign (4711,one_integer) assign ([4711,0.815],two_numbers)
This code is displayed as empty_tuple := [] one_integer := 4711 two_numbers := [4711,0.815]
7.5.4 Tuple Creation 221
This is useful for constant tuples with a fixed (small) length. More general tuples can be created by successive application of the concatenation or the operator insert together with variables, expressions or constants. If we want to generate a tuple of length 100, where each element has the value 4711, it might be done like this: assign ([],tuple) for (1,100,1,i) assign ([tuple,4711],tuple) endfor which is displayed as tuple := [] for i := 1 to 100 by 1 tuple := [tuple,4711] endfor
Because this is not very convenient a special function called gen_tuple_const is available to construct a tuple of a given length, where each element has the same value. Using this function, the program from above is reduced to: assign(gen_tuple_const(100,4711),tuple) which is displayed as tuple := gen_tuple_const(100,4711)
If we want to construct a tuple with the same length as a given tuple there are two ways to get an easy solution, The first one is based on gen_tuple_const: assign(gen_tuple_const(|tuple_old|,4711),tuple_new) which is displayed as tuple_new := gen_tuple_const(|tuple_old|,4711)
The second one is a bit tricky and uses arithmetic functions: assign((tuple_old * 0) + 4711,tuple_new) which is displayed as tuple_new := (tuple_old * 0) + 4711
222 HDevelop Language
Operation Meaning a1 / a2 division a1 - a2 subtraction
-a negation
HALCON operator tuple_div a1 * a2 multiplication tuple_mult a1 % a2 modulus tuple_mod a1 + a2 addition tuple_add tuple_sub tuple_neg
Table 7.7: Basic arithmetic operations.
Here we get first a tuple of the same length with every element set to zero. Then, we add the constant to each element.
In the case of tuples with different values we have to use the loop version to assign the values to each position: assign([],tuple) for (1,100,1,i) assign([tuple,i*i],tuple) endfor which is displayed as tuple := [] for i := 1 to 100 by 1 tuple := [tuple,i*i] endfor
In this example we construct a tuple with the square values from 1
2 to 100
2
.
7.5.5
Basic Arithmetic Operations
See
for an overview of the available basic arithmetic operations.
All operations are left-associative, except the right-associative unary minus operator. The evaluation usually is done from left to right. However, parentheses can change the order of evaluation and some operators have a higher precedence than others (see section
The arithmetic operations in HDevelop match the usual definitions. Expressions can have any number of parentheses.
The division operator (a1 / a2) can be applied to integer as well as to real. The result is of type real, if at least one of the operands is of type real. If both operands are of type integer, the division is an integer division. The remaining arithmetic operators (multiplication, addition, subtraction, and
7.5.6 Bit Operations 223
Operation Meaning lsh(i1,i2) left shift
HALCON operator tuple_lsh rsh(i1,i2) right shift i1 band i2 bitwise and i1 bxor i2 bitwise xor tuple_rsh tuple_band tuple_bxor i1 bor i2 bitwise or bnot i tuple_bor bitwise complement tuple_bnot
Table 7.8: Bit operations.
negation) can be applied to either integer or real numbers. If at least one operand is of type real, the result will be a real number as well.
Examples:
Expression
4/3
Result
1
4/3.0
1.3333333
(4/3) * 2.0
2.0
Simple examples can be found in the program arithmetic.dev.
7.5.6
Bit Operations
This section describes the operators for bit processing of numbers. The operands have to be integers.
The result of lsh(i1,i2) is a bitwise left shift of i1 that is applied i2 times. If there is no overflow this is equivalent to a multiplication by 2 i2
. The result of rsh(i1,i2) is a bitwise right shift of i1 that is applied i2 times. For non-negative i1 this is equivalent to a division by 2 i2
. For negative i1 the result depends on the used hardware. For lsh and rsh the result is undefined if the second operand has a negative value or the value is larger than 32. More examples can be found in the program bit.dev.
7.5.7
String Operations
There are several string operations available to modify, select, and combine strings. Furthermore, some operations allow to convert numbers (real and integer) to strings.
$ (string conversion)
See also: tuple_string
$ converts numbers to strings or modifies strings. The operation has two operands: The first one (left of the $) is the number that has to be converted. The second one (right of the $) specifies the conversion.
It is comparable to the format string of the printf() function in the C programming language. This format string consists of the following four parts
224 HDevelop Language
<flags><width>.<precision><conversion> or as a regular expression:
[-+ #]?([0-9]+)?(\.[0-9]*)?[doxXfeEgGsb]?
(which roughly translates to zero or more of the characters in the first bracket pair followed by zero or more digits, optionally followed by a dot which may be followed by digits followed by a conversion character from the last bracket pair).
Some conversion examples might show it best:
Input Output
23 \$
'10.2f'
23 \$
'-10.2f'
'
'23.00
23.00
4 \$
'.7f' '4.0000000'
1234.56789 \$
'+10.3f' ' +1234.568'
'
'
255 \$
255 \$
0xff \$
'x'
'X'
'.5d'
'total' \$ '10s'
'total' \$ '-10s'
'total' \$ '10.3' '
'ff'
'FF'
'
'00255'
'total total
' tot
'
' flags Zero or more flags, in any order, which modify the meaning of the conversion specification. Flags may consist of the following characters: v$s v1 + v2 strchr(s1,s2) strstr(s1,s2) strrchr(s1,s2) strrstr(s1,s2) convert v using specification s concatenate v1 and v2 search character s2 in s1 search substring s2 in s1 search character s2 in s1 (reverse) search substring s2 in s1 (reverse) strlen(s) s{i} s{i1:i2} split(s1,s2) regexp_test(s1,s2) length of string select character at position i; 0 <= i <= strlen(s) select substring from position i1 to position i2 split s1 in substrings at s2 regexp_match(s1,s2) extract substrings of s1 matching the regular expression s2 regexp_replace(s1,s2,s3) replace substrings of s1 matching the regular expression s2 with s3 regexp_select(s1,s2) select tuple elements from s1 matching the regular expression s2 return how many tuple elements in s1 match the regular expression s2
Table 7.9: String operations.
7.5.7 String Operations 225
- The result of the conversion is left justified within the field.
+ The result of a signed conversion always begins with a sign, + or -.
<space> If the first character of a signed conversion is not a sign, a space character is prefixed to the result. This means that if the space flag and + flag both appear, the space flag is ignored.
# The value is to be converted to an “alternate form”. For d and s (see below) conversions, this flag has no effect. For o conversion (see below), it increases the precision to force the first digit of the result to be a zero. For x or X conversion (see below), a non-zero result has 0x or 0X prefixed to it. For e, E, f, g, and G conversions, the result always contains a radix character, even if no digits follow the radix character. For g and G conversions, trailing zeros are not removed from the result, contrary to usual behavior.
width An optional string of decimal digits to specify a minimum field width. For an output field, if the converted value has fewer characters than the field width, it is padded on the left (or right, if the left-adjustment flag - has been given) to the field width.
precision The precision specifies the minimum number of digits to appear for integer conversions (the field is padded with leading zeros), the number of digits to appear after the radix character for the e and f conversions, the maximum number of significant digits for the g conversion, or the maximum number of characters to be printed from a string conversion. The precision takes the form of a period . followed by a decimal digit string. A null digit string is treated as a zero.
conversion A conversion character indicates the type of conversion to be applied: d, o, x, X The integer argument is printed in signed decimal (d), unsigned octal (o), or unsigned hexadecimal notation (x and X). The x conversion uses the numbers and lower-case letters 0123456789abcdef, and the X conversion uses the numbers and upper-case letters
0123456789ABCDEF. The precision component of the argument specifies the minimum number of digits to appear. If the value being converted can be represented in fewer digits than the specified minimum, it is expanded with leading zeroes. The default precision is 1. The result of converting a zero value with a precision of 0 is no characters.
f The floating-point number argument is printed in decimal notation in the style [-]ddd.ddd, where the number of digits after the radix character, ., is equal to the precision specification. If the precision is omitted from the argument, six digits are output; if the precision is explicitly 0, no radix appears.
e,E The floating-point-number argument is printed in the style [-]d.ddde+dd, where there is one digit before the radix character, and the number of digits after it is equal to the precision.
When the precision is missing, six digits are produced; if the precision is 0, no radix character appears. The E conversion character produces a number with E introducing the exponent instead of e. The exponent always contains at least two digits. However, if the value to be printed requires an exponent greater than two digits, additional exponent digits are printed as necessary.
g, G The floating-point-number argument is printed in style f or e (or in style E in the case of a
G conversion character), with the precision specifying the number of significant digits. The style used depends on the value converted; style e is used only if the exponent resulting from the conversion is less than -4 or greater than or equal to the precision. Trailing zeros are removed from the result. A radix character appears only if it is followed by a digit.
226 HDevelop Language
s The argument is taken to be a string, and characters from the string are printed until the end of the string or the number of characters indicated by the precision specification of the argument is reached. If the precision is omitted from the argument, it is interpreted as infinite and all characters up to the end of the string are printed.
In no case does a nonexistent or insufficient field width cause truncation of a field; if the result of a conversion is wider than the field width, the field is simply expanded to contain the conversion result.
Examples for the string conversion can be found in the program string.dev.
+ (string concatenation)
The string concatenation (+) can be applied in combination with strings or all numerical types; if necessary, the operands are first transformed into strings (according to their standard representation). At least one of the operands has to be already a string so that the operator can act as a string concatenator. In the following example a file name (e.g., ’Name5.tiff’) is generated. For this purpose two string constants
(’Name’ and ’.tiff’) and an integer value (the loop-index i) are concatenated: for i := 1 to 5 by 1 read_image (Image,
'Name'+i+'.tiff') endfor str(r)chr
See also: tuple_strchr
, tuple_strrchr str(r)chr(s1,s2) returns the index of the first (last) occurrence of one of the character in s2 in string s1, or -1 if none of the characters occur in the string. s1 may be a single string or a tuple of strings.
str(r)str
See also: tuple_strstr
, tuple_strrstr str(r)str(s1,s2) returns the index of the first (last) occurrence of string s2 in string s1, or -1 if s2 does not occur in the string. s1 may be a single string or a tuple of strings.
strlen
See also: tuple_strlen strlen(s) returns the number of characters in s.
{}
See also: tuple_str_bit_select s{i} selects a single character (specified by index position) from s. The index ranges from zero to the length of the string minus 1. The result of the operator is a string of length one.
s{i1:i2} returns all characters from the first specified index position (i1) up to the second specified position (i2) in s as a string. The index ranges from zero to the length of the string minus 1.
7.5.7 String Operations 227
split
See also: tuple_split split(s1,s2) divides the string s1 into single substrings. The string is split at those positions where it contains a character from s2. As an example the result of split(
'/usr/image:/usr/proj/image',':') consists of the two strings
[
'/usr/image','/usr/proj/image']
Regular Expressions
HDevelop provides string functions that use Perl compatible regular expressions.
Detailed information about them can be found in the Reference Manual at the descriptions of the corresponding operators, which have the same name but start with tuple_.
In particular, at the description of tuple_regexp_match you find further information about the used syntax, a list of possible options, and a link to suitable literature about regular expressions.
regexp_match
See also: tuple_regexp_match regexp_match(s1,s2) searches for elements of the tuple s1 that match the regular expression s2.
It returns a tuple with the same size as the input tuple (exceptions exist when working with capturing groups, see the description of tuple_regexp_match in the Reference Manual for details). The resulting tuple contains the matching results for each tuple element of the input tuple. For a successful match the matching substring is returned. Otherwise, an empty string is returned.
regexp_replace
See also: tuple_regexp_replace regexp_replace(s1,s2,s3) replaces substrings in s1 that match the regular expression s2 with the string given in s3. By default, only the first matching substring of each element in s1 is replaced. To replace all occurrences, the option ’replace_all’ has to be set in s2 (see tuple_regexp_replace
).
For example: assign(regexp_replace(List,
'\\.jpg$', '.png'), List) substitutes file names that look like JPEG images with PNG images.
228 HDevelop Language
Operation Meaning t1 < t2 less than
HALCON operator tuple_less t1 > t2 greater than t1 <= t2 less or equal tuple_greater tuple_less_equal t1 >= t2 greater of equal tuple_greater_equal t1 = t2 t1 # t2 equal not equal tuple_equal tuple_not_equal
Table 7.10: Comparison operations.
regexp_select
See also: tuple_regexp_select regexp_select(s1,s2) returns only the elements of the tuple s1 that match the regular expression s2. In contrast to regexp_match, the original tuple elements instead of the matching substrings are returned. Tuple elements that do not match the regular expression are discarded.
For example: assign(regexp_select(List,
'\\.jpg$'), Selection) sets Selection to all the strings from List that look like file names of JPEG images. Please note that the backslash character has to be escaped to be preserved.
regexp_test
See also: tuple_regexp_test regexp_test(s1,s2) returns the number of elements of the tuple s1 that match the regular expression s2. Additionally, a short-hand notation of the operator is available, which is convenient in conditional expressions: s1 =~ s2
7.5.8
Comparison Operations
In HDevelop, the comparison operations are defined not only on atomic values, but also on tuples with an arbitrary number of elements. They always return values of type boolean.
shows all comparison operations.
t1 = t2 and t1 # t2 are defined on all types. Two tuples are equal (true), if they have the same length and all the data items on each index position are equal. If the operands have different types (integer and real), the integer values are first transformed into real numbers. Values of type string cannot be mixed up with numbers, i.e., string values are considered to be not equal to values of other types.
7.5.9 Boolean Operations 229
1st Operand
1
2nd Operand
1.0
[]
’’
[1,’2’]
[]
[]
[1,2]
[1,2,3] [1,2]
[4711,’Hugo’] [4711,’Hugo’]
’Hugo’ ’hugo’
2
2
[5,4,1]
[2,1] true
’Hugo’
1
1.0
[5,4]
[2,0] false
’hugo’
=
>
>
>
>
>
<
=
=
=
=
=
Operation Result
= true true false false false true false true true true true true true
Table 7.11: Examples for the comparison of tuples.
Operation Meaning HALCON operator l1 and l2 logical ’and’ tuple_and l1 xor l2 logical ’xor’ tuple_xor l1 or l2 logical ’or’ not l negation tuple_or tuple_not
Table 7.12: Boolean operations.
The four comparison operations compute the lexicographic order of tuples. On equal index positions the types must be identical, however, values of type integer, real, and boolean are adapted automatically. The lexicographic order applies to strings, and the boolean false is considered to be smaller than the boolean true (false < true). In the program compare.dev you can find examples for the comparison operations.
7.5.9
Boolean Operations
The boolean operations and, xor, or, and not are defined only for tuples of length 1. l1 and l2 is set to true (1) if both operands are true (1), whereas l1 xor l2 returns true (1) if exactly one of both operands is true. l1 or l2 returns true (1) if at least one of the operands is true (1). not l returns true (1) if the input is false (0), and false (0), if the input is true (1).
230 HDevelop Language
7.5.10
Trigonometric Functions
All these functions work on tuples of numbers as arguments. The input can either be of type integer or real. However, the resulting type will be of type real. The functions are applied to all tuple values, and the resulting tuple has the same length as the input tuple. For atan2 the two input tuples have to be of equal length.
shows the provided trigonometric functions. For the trigonometric functions the angle is specified in radians.
Operation sin(a) cos(a)
Meaning sine of a cosine of a
HALCON Operator tuple_sin tuple_cos tan(a) asin(a) acos(a) atan(a) tangent of a arc sine of a in the interval [−π/2, π/2], a ∈ [−1, 1] tuple_tan tuple_asin arc cosine a in the interval [−π/2, π/2], a ∈ [−1, 1] tuple_acos arc tangent a in the interval [−π/2, π/2], a ∈ [−∞, +∞] tuple_atan atan2(a1,a2) arc tangent a1/a2 in the interval [−π, π] sinh(a) hyperbolic sine of a cosh(a) hyperbolic cosine of a tanh(a) hyperbolic tangent of a tuple_atan2 tuple_sinh tuple_cosh tuple_tanh
Table 7.13: Trigonometric functions.
7.5.11
Exponential Functions
All these functions work on tuples of numbers as arguments. The input can either be of type integer or real. However, the resulting type will be of type real. The functions are applied to all tuple values and the resulting tuple has the same length as the input tuple. For pow and ldexp the two input tuples have to be of equal length.
See
for the provided exponential functions.
Operation exp(a)
Meaning exponential function ea
HALCON operator tuple_exp log(a) natural logarithm ln(a), a > 0 tuple_log log10(a) pow(a1,a2) decadic logarithm, log
10
(a), a > 0 tuple_log10 a1 a2 ldexp(a1,a2) a1 · 2 a2 tuple_pow tuple_ldexp
Table 7.14: Exponential functions.
7.5.12 Numerical Functions 231
Operation min(t) fabs(a) ceil(a) floor(a) fmod(a1,a2) sgn(a)
Meaning minimum value of the tuple
HALCON operator tuple_min min2(t1,t2) max(t) max2(t1,t2) sum(t) mean(a) element-wise minimum of two tuples maximum value of the tuple element-wise maximum of two tuples tuple_min2 tuple_max tuple_max2 sum of all tuple elements or string concatenation tuple_sum mean value tuple_mean standard deviation tuple_deviation deviation(a) cumul(a) median(a) cumulative sums of a tuple median of a tuple select_rank(a,i) element at rank i of a tuple
√ sqrt(a) square root a deg(a) rad(a) real(a) convert radians to degrees convert degrees to radians convert integer to real int(a) round(a) abs(a) truncate real to integer convert real to integer absolute value of a (integer or real) tuple_cumul tuple_median tuple_select_rank tuple_sqrt tuple_deg tuple_rad tuple_real tuple_int tuple_round tuple_abs absolute value of a (always real) smallest integer value not smaller than a largest integer value not greater than a tuple_fabs tuple_ceil tuple_floor fractional part of a1/a2, with the same sign as a1 tuple_fmod element-wise sign of a tuple tuple_sgn
Table 7.15: Numerical functions.
7.5.12
Numerical Functions
The numerical functions shown in
work on different data types.
The functions min and max select the minimum and the maximum values of the tuple values. All of these values either have to be of type string, or integer/real. It is not allowed to mix strings with numerical values. The resulting value will be of type real, if at least one of the elements is of type real. If all elements are of type integer the resulting value will also be of type integer. The same applies to the function sum that determines the sum of all values. If the input arguments are strings, string concatenation will be used instead of addition.
The functions mean, deviation, sqrt, deg, rad, fabs, ceil, floor and fmod work with integer and real; the result is always of type real. The function mean calculates the mean value and deviation the standard deviation of numbers. sqrt calculates the square root of a number.
232 HDevelop Language
cumul returns the different cumulative sums of the corresponding elements of the input tuple, and median calculates the median of a tuple. For both functions, the resulting value will be of type real, if at least one of the elements is of type real. If all elements are of type integer the resulting value will also be of type integer. select_rank returns the element at rank i and works for tuples containing int or real values. The index i is of type int.
deg and rad convert numbers from radians to degrees and from degrees to radians, respectively.
real converts an integer to a real. For real as input it returns the input. int converts a real to an integer and truncates it. round converts a real to an integer and rounds the value. For integer it returns the input. The function abs always returns the absolute value that is of the same type as the input value.
The following example (file name: euclid_distance.dev) shows the use of some numerical functions:
V1 := [18.8,132.4,33,19.3]
V2 := [233.23,32.786,234.4224,63.33]
Diff := V1 - V2
Distance := sqrt(sum(Diff * Diff))
Dotvalue := sum(V1 * V2)
First, the Euclidian distance of the two vectors V1 and V2 is computed, by using the formula: d = s
X
(V 1 i
− V 2 i
)
2 i
The difference and the multiplication (square) are successively applied to each element of both vectors.
Afterwards sum computes the sum of the squares. Then the square root of the sum is calculated. After that the dot product of V1 and V2 is determined by the formula: hV 1, V 2i =
X
(V 1 i
∗ V 2 i
) i
7.5.13
Miscellaneous Functions
sort sorts the tuple values in ascending order, that means, that the first value of the resulting tuple is the smallest one. But again: strings must not be mixed up with numbers. sort_index sorts the tuple values in ascending order, but in contrast to sort it returns the index positions (0..) of the sorted values.
The function inverse reverses the order of the tuple values. Both sort and inverse are identical, if the input is empty, if the tuple is of length 1, or if the tuple contains only one value in all positions, e.g.,
[1,1,...,1].
is_number returns true for variables of the type integer or real and for variables of the type string that represent a number.
The function number converts a string representing a number to an integer or a real depending on the type of the number. Note that strings starting with 0x are interpreted as hexadecimal numbers, and
7.5.14 Operation Precedence 233
Operation sort(t)
Meaning sorting in increasing order sort_index(t) return index instead of values inverse(t) reverse the order of the values is_number(v) test if value is a number
HALCON operator tuple_sort tuple_sort_index tuple_inverse tuple_is_number number(v) convert string to a number environment(s) value of an environment variable ord(a)
ASCII number of a character chr(a) ords(s) chrt(i) rand(a) create random numbers tuple_number tuple_environment tuple_ord convert an ASCII number to a character tuple_chr
ASCII number of a tuple of strings tuple_ords convert a tuple of integers into a string tuple_chrt tuple_rand
Table 7.16: Miscellaneous functions.
strings starting with 0 (zero) as octal numbers; for example, the string ’20’ is converted to the integer
20, ’020’ to 16, and ’0x20’ to 32. If called with a string that does not represent a number or with a variable of the type integer or real, number returns a copy of the input.
environment returns the value of an environment variable. Input is the name of the environment variable as a string.
ord gives the ASCII number of a character as an integer. chr converts an ASCII number to a character.
ords converts a tuple of strings into a tuple of (ASCII) integers. chrt converts a tuple of integers into a string.
7.5.14
Operation Precedence
See
for the precedence of the operations for control data. Some operations (like functions, |
|, t[], etc.) are left out, because they mark their arguments clearly.
7.6
Reserved Words
The identifiers listed in
on page
are reserved words and their usage is strictly limited to their predefined meaning. They cannot be used as variable names.
7.7
Control Flow Operators
The operators introduced in this section execute a block of operators conditionally or repeatedly. Usually, these operators come in pairs: One operator marks the start of the block while the other marks the end.
234 HDevelop Language
band bxor bor and xor or
# =
<= >= < >
+ -
/ * %
- (unary minus) not
$
Table 7.17: Operation precedence (increasing from top to bottom).
The code lines inbetween are referred to as the body of a control flow structure.
When you enter a control flow operator to start a block, HDevelop also adds the corresponding closing operator by default to keep the program code balanced. In addition, the IC is placed between the control flow operators. This is fine for entering new code blocks. If you want to add control flow operators to existing code, you can also add the operators individually. Keep in mind, however, that a single control flow operator is treated as invalid code until its counterpart is entered as well.
In the following, <condition> is an expression that evaluates to an integer or boolean value. A condition is false if the expression evaluates to 0 (zero). Otherwise, it is true. HDevelop provides the following operators to control the program flow: if
...
endif
This control flow structure executes a block of code conditionally. The operator if takes a condition as its input parameter. If the condition is true, the body is executed. Otherwise the execution is continued at the operator call that follows the operator endif
.
To enter both if and endif at once, select the operator if in the operator window and make sure the check box next to the operator is ticked.
if (<condition>)
...
endif ifelse
( if
...
else
...
endif
) Another simple control flow structure is the condition with alternative.
If the condition is true, the block between if and else is executed. If the condition is false, the part between else and endif is executed.
To enter all three operators at once, select the operator ifelse in the operator window and make sure the check box next to the operator is ticked.
if (<condition>)
...
7.7 Control Flow Operators 235
abs assign bnot by chrt acos atan bor catch comment and atan2 break ceil continue cosh else endtry cumul elseif endwhile deg endfor environment exp floor fabs fmod false for
H_MSG_FAIL H_MSG_FALSE H_MSG_TRUE asin band bxor chr cos deviation endif exit find gen_tuple_const
H_MSG_VOID if inverse log10 mean not ords real ifelse is_number lsh median insert ldexp max min int log max2 min2 number pow or rad ord rand regexp_match regexp_replace regexp_select regexp_test remove round rsh sin sinh split strlen subset throw uniq sqrt strrchr sum to until repeat select_rank sort stop strrstr tan true while return sgn sort_index strchr strstr tanh try xor
Table 7.18: Reserved words.
else
...
endif elseif
This operator is similar to the else
-part of the previous control flow structure. However, it allows to test for an additional condition. The block between elseif and endif is executed if
<condition1> is false and <condition2> is true.
elseif may be followed by an arbitrary number of additional elseif instructions. The last elseif may be followed by a single else instruction.
if (<condition1>)
236 HDevelop Language
...
elseif (<condition2>)
...
endif
This is syntactically equivalent and thus a shortcut for the following code block: if (<condition1>)
...
else if (<condition2>)
...
endif endif while
...
endwhile
This is a looping control flow structure. As long as the condition is true, the body of the loop is executed. In order to enter the loop, the condition has to be true in the first place.
The loop can be restarted and terminated immediately with the operator continue and break
, respectively (see below).
To enter both while and endwhile at once, select the operator while in the operator window and make sure the check box next to the operator is ticked.
while (<condition>)
...
endwhile repeat
...
until
This loop is similar to the while loop with the exception that the condition is tested at the end of the loop. Thus, the body of a repeat
...
until loop is executed at least once. Also in contrast to the while loop, the loop is repeated if the condition is false, i.e., until it is finally true.
To enter both repeat and until at once, select the operator until in the operator window and make sure the check box next to the operator is ticked.
repeat
...
until (<condition>) for
...
endfor
The for loop is controlled by a start and an end value and an increment value, step, that determines the number of loop steps. These values may also be expressions, which are evaluated immediately before the loop is entered. The expressions may be of type integer or of type real.
If all input values are of type integer, the loop variable will also be of type integer. In all other cases the loop variable will be of type real.
Please note that the for loop is displayed differently in the program window than entered in the operator window. What you enter in the operator window as for(start,end,step,index ) is displayed in the program window as:
7.7 Control Flow Operators 237
for <index> := <start> to <end> by <step>
...
endfor
To enter both for and endfor at once, select the operator for in the operator window and make sure the check box next to the operator is ticked.
The start value is assigned to the index variable. The loop is executed as long as the following conditions are true: 1) The step value is positive, and the loop index is smaller than or equal to the end value. 2) The step value is negative, and the loop index is greater than or equal to the end value. After a loop cycle, the loop index is incremented by the step value and the conditions are evaluated again.
Thus, after executing the following lines, for i := 1 to 5 by 1 j := i endfor i is set to 6 and j is set to 5, while in for i := 5 to 1 by -1 j := i endfor i is set to 0, and j is set to 1.
The loop can be restarted and terminated immediately with the operator continue and break
, respectively. (see below).
Please note, that the expressions for start and termination value are evaluated only once when entering the loop . A modification of a variable that appears within these expressions has no influence on the termination of the loop. The same applies to the modifications of the loop index. It also has no influence on the termination. The loop value is assigned to the correct value each time the for operator is executed.
If the for loop is left too early (e.g., if you press Stop and set the PC) and the loop is entered again, the expressions will be evaluated, as if the loop were entered for the first time.
In the following example the sine from 0 up to 6π is computed and printed into the graphical window (file name: sine.dev): old_x := 0 old_y := 0 dev_set_color (
'red') dev_set_part(0, 0, 511, 511) for x := 1 to 511 by 1 y := sin(x / 511.0 * 2 * 3.1416 * 3) * 255 disp_line (WindowID, -old_y+256, old_x, -y+256, x) old_x := x old_y := y endfor
238 HDevelop Language
In this example the assumption is made that the window is of size 512×512. The drawing is always done from the most recently evaluated point to the current point.
continue
The operator continue forces the next loop cycle of a for
, while
, or repeat loop. The loop condition is tested, and the loop is executed depending on the result of the test.
In the following example, a selection of RGB color images is processed. Images with channel numbers other than three are skipped through the use of the operator continue
. An alternative is to invert the condition and put the processing instructions between if and endif
. But the form with continue tends to be much more readable when very complex processing with lots of lines of code is involved.
i := |Images| while (i)
Image := Images[i] count_channels (Image, Channels) if (Channels # 3) continue endif
* extensive processing of color image follows endwhile break
The opeator break enables you to exit for
, while
, and repeat loops. The program is then continued at the next line after the end of the loop.
A typical use of the operator break is to terminate a for loop as soon as a certain condition becomes true, e.g., as in the following example:
Number := |Regions|
AllRegionsValid := 1
* check whether all regions have an area <= 30 for i := 1 to Number by 1
ObjectSelected := Regions[i] area_center (ObjectSelected, Area, Row, Column) if (Area > 30)
AllRegionsValid := 0 break () endif endfor
In the following example, the operator break is used to terminate an (infinite) while loop as soon as one clicks into the graphics window: while (1) grab_image (Image, FGHandle) dev_error_var (Error, 1) dev_set_check (
'~give_error') get_mposition (WindowHandle, R, C, Button)
7.8 Error Handling 239
dev_error_var (Error, 0) dev_set_check (
'give_error') if ((Error = H_MSG_TRUE) and (Button # 0)) break () endif endwhile stop
The operator stop stops the program after the operator is executed. The program can be continued by pressing the Step Over or Run button.
exit
The exit operator terminates the HDevelop session.
return
The operator return returns from the current procedure call to the calling procedure. If return is called in the main procedure, the PC jumps to the end of the program, i.e., the program is finished.
try
...
catch
...
endtry
This control flow structure enables dynamic exception handling in HDevelop.
The program block between the operators try and catch is watched for exceptions, i.e., runtime errors. If an exception occurs, diagnostic data about what caused the exception is stored in an exception tuple. The exception tuple is passed to the catch operator, and program execution continues from there. The program block between the operators catch and endtry is intended to analyze the exception data and react to it accordingly. If no exception occurs, this program block is never executed.
See section “Error Handling” on page
239 , and the reference manual, e.g., the operator
try for detailed information.
throw
The operator throw allows to generate user-defined exceptions.
7.8
Error Handling
This section describes how errors are handled in HDevelop programs. When an error occurs, the default behavior of HDevelop is to stop the program execution and display an error message box. While this is certainly beneficial at the time the program is developed, it is usually not desired when the program is actually deployed. A finished program should react to errors itself. This is of particular importance if the program interacts with the user.
There are basically two approaches to error handling in HDevelop:
• tracking the return value (error code) of operator calls
• using exception handling
A major difference between these approaches is the realm of application: The first method handles errors inside the procedure in which they occur. The latter method allows errors to work their way up in the call stack until they are finally dealt with.
240 HDevelop Language
7.8.1
Tracking the Return Value of Operator Calls
The operator dev_set_check specifies if error message boxes are displayed at all.
To turn message boxes off, use dev_set_check(
'~give_error')
HDevelop will then ignore any errors in the program. Consequently, the programmer has to take care of the error handling. Every operator call provides a return value (or error code) which signals success or failure of its execution. This error code can be accessed through a designated error variable: dev_error_var(
'ErrorCode', 1)
This operator call instantiates the variable ErrorCode. It stores the error code of the last executed operator. Using this error code, the program can depend its further flow on the success of an operation.
...
if (ErrorCode # H_MSG_TRUE)
* react to error endif
* continue with program
...
The error message related to a given error code can be obtained with the operator get_error_text
.
This is useful when reporting errors back to the user of the program.
Due to the lack of global variables in HDevelop, errors have to be responded to in the same procedure where they occur. If the error is to be handled in a calling procedure, an appropriate output control variable has to be added to the interface of each participating procedure.
7.8.2
Exception Handling
HDevelop supports dynamic exception handling, which is comparable to the exception handling in C++ and C#.
A block of program lines is watched for run-time errors. If an error occurs, an exception is raised and an associated exception handler is called. An exception handler is just another block of program lines, which is invisible to the program flow unless an error occurs. The exception handler may directly act on the error or it may pass the associated information (i.e., the exception) on to a parent exception handler.
This is also known as rethrowing an exception.
In contrast to the tracking method described in the previous section, the exception handling requires
HDevelop to be set up to stop on errors. This is the default behavior. It can also be turned on explicitly: dev_set_check(
'give_error')
7.8.2 Exception Handling 241
Furthermore, HDevelop can be configured to let the user choose whether or not an exception is thrown, or to throw exceptions automatically. This behavior is set in the preferences tab General Options ->
Experienced User.
An HDevelop exception is a tuple containing data related to a specific error. It always contains the error code as the first item. The operator dev_get_exception_data provides access to the elements of an exception tuple.
HDevelop exception handling is applied in the following way:
...
try
* start block of watched program lines
...
catch(Exception)
* get error code
ErrorCode := Exception[0]
* react to error endtry
* program continues normally
...
242 HDevelop Language
7.9
Summary of HDevelop operations
Functionality concatenation number of elements select tuple element select tuple slice select elements remove tuple elements lookup tuple values unify tuple elements tuple creation division multiplication modulo addition subtraction negation left shift right shift bitwise and bitwise xor bitwise or bitwise complement string conversion string concatenation search character search character (reverse) search string search string (reverse) length of string select character select substring split string regular expression match regular expression replace regular expression select regular expression test less than greater than less or equal greater or equal equal not equal logical and logical xor
HDevelop Operation
[t1,t2]
|t| t[i] t[i1:i2] subset(t,i) remove(t,i) find(t1,t2) uniq(t) gen_tuple_const(i1,i2) a1 / a2 a1 * a2 a1 % a2 a1 + a2 a1 - a2
-a
HALCON operator tuple_concat tuple_length tuple_select tuple_select_range tuple_select tuple_remove tuple_find tuple_uniq tuple_gen_const tuple_div tuple_mult tuple_mod tuple_add tuple_sub tuple_neg lsh(i1,i2) rsh(i1,i2) i1 band i2 i1 bxor i2 i1 bor i2 bnot i v$s v1 + v2 tuple_lsh tuple_rsh tuple_band tuple_bxor tuple_bor tuple_bnot tuple_string tuple_concat strchr(s1,s2) strrchr(s1,s2) strstr(s1,s2) strrstr(s1,s2) tuple_strchr tuple_strrchr tuple_strstr tuple_strrstr strlen(s) s{i} s{i1:i2} split(s1,s2) tuple_strlen tuple_str_bit_select tuple_str_bit_select tuple_split regexp_match(s1,s2) tuple_regexp_match regexp_replace(s1,s2,s3) tuple_regexp_replace regexp_select(s1,s2) regexp_test(s1,s2) tuple_regexp_select tuple_regexp_test t1 < t2 t1 > t2 t1 <= t2 t1 >= t2 t1 = t2 t1 # t2 l1 and l2 l1 xor l2 tuple_less tuple_greater tuple_less_equal tuple_greater_equal tuple_equal tuple_not_equal tuple_and tuple_xor
logical or negation sine cosine tangent arc sine arc cosine arc tangent arc tangent2 hyperbolic sine hyperbolic cosine hyperbolic tangent exponential function natural logarithm decadic logarithm power function ldexp function minimum element-wise minimum maximum element-wise maximum sum function mean value standard deviation cumulative sum median element rank square root radians to degrees degrees to radians integer to real real to integer real to integer absolute value floating absolute value ceiling function floor function fractional part element-wise sign sort elements sort elements (returns index) reverse element order test for numeric value string to number environment variable character to ASCII number
ASCII number to character l1 or l2 not l sin(a) cos(a) tan(a) asin(a) acos(a) atan(a) atan2(a1,a2) sinh(a) cosh(a) tanh(a) exp(a) log(a) log10(a) pow(a1,a2) ldexp(a1,a2) min(t) min2(t1,t2) max(t) max2(t1,t2) sum(t) mean(a) deviation(a) cumul(a) median(a) select_rank(a,i) sqrt(a) deg(a) rad(a) real(a) int(a) round(a) abs(a) fabs(a) ceil(a) floor(a) fmod(a1,a2) sgn(a) sort(t) sort_index(t) inverse(t) is_number(v) number(v) environment(s) ord(a) chr(a)
7.9 Summary of HDevelop operations 243
tuple_or tuple_not tuple_sin tuple_cos tuple_tan tuple_asin tuple_acos tuple_atan tuple_atan2 tuple_sinh tuple_cosh tuple_tanh tuple_exp tuple_log tuple_log10 tuple_pow tuple_ldexp tuple_min tuple_min2 tuple_max tuple_max2 tuple_sum tuple_mean tuple_deviation tuple_cumul tuple_median tuple_select_rank tuple_sqrt tuple_deg tuple_rad tuple_real tuple_int tuple_round tuple_abs tuple_fabs tuple_ceil tuple_floor tuple_fmod tuple_sgn tuple_sort tuple_sort_index tuple_inverse tuple_is_number tuple_number tuple_environment tuple_ord tuple_chr
244 HDevelop Language
tuple of strings to ASCII numbers ords(s) tuple of integers to string chrt(i) random number rand(a) tuple_ords tuple_chrt tuple_rand
7.10 HDevelop Error Codes
7.10
HDevelop Error Codes
21000 HALCON operator error
21001 User defined exception (’throw’)
21002 User defined error during execution
21003 User defined operator does not implement execution interface
21010 HALCON license error
21011 HALCON startup error
21012 HALCON operator error
21020 Format error: file is not a valid HDevelop program or procedure
21021 File is no HDevelop program or has the wrong version
21022 External procedure could not be decompressed
21023 External procedure could not be compressed and encrypted for saving
21030 The program was modified inconsistently outside HDevelop.
21031 The program was modified outside HDevelop: inconsistent procedure lines.
21032 The program was modified outside HDevelop: unmatched control statements
21033 renaming of procedure failed
21040 Unable to open file
21041 Unable to read from file
21042 Unable to write to file
21043 Unable to rename file
21044 Unable to open file: invalid file name
21050 Old program version: Not supported for hdevelop_demo
21051 Wrong program crypt code: Not allowed in hdevelop_demo
21052 Inserting procedures is not supported in hdevelop_demo
21060 Iconic variable is not instantiated
21061 Control variable is not instantiated (no value)
21062 Wrong number of control values
21063 Wrong value type of control parameter
21064 Wrong value of control parameter
21065 Control parameter does not contain a variable
21066 Wrong number of control values in condition variable
21067 Wrong type: Condition variable must be an integer or boolean
21068 Variable names must not be empty
21069 Variable names must not start with a number
21070 Invalid variable name
21071 Invalid name for a control variable: the name is already used for an iconic variable
21072 Invalid name for an iconic variable: the name is already used for a control variable
21073 For loop variable must be a number
21074 Step parameter of for loop must be a number
21075 End parameter of for loop must be a number
21076 Variable names must not be a reserved expression
21100 Access to an erroneous expression
21101 Wrong index in expression list
21102 Empty expression
21103 Empty expression argument
21104 Syntax error in expression
245
246 HDevelop Language
21105 Wrong number of function arguments in expression
21106 Expression expected
21107 Unary expression expected
21108 Expression list expected
21109 Function arguments in parentheses expected
21110 One function argument in parentheses expected
21111 Two function arguments in parentheses expected
21112 Three function arguments in parentheses expected
21113 Four function arguments in parentheses expected
21114 Five function arguments in parentheses expected
21115 Right parenthesis ’)’ expected
21116 Right curly brace ’}’ expected
21117 Right square bracket ’]’ expected
21118 Unmatched right parenthesis ’)’ found
21119 Unmatched right curly brace ’}’ found
21120 Unmatched right square bracket ’]’ found
21121 Second bar ’|’ expected
21122 Function name expected before parentheses
21123 Unterminated string detected
21124 Invalid character in an expression identifier detected
21125 Parameter expression expected
21200 Syntax error in operator expression
21201 Identifier (operator or variable name) expected
21202 Syntax error in parameter list
21203 Parenthesis expected
21204 No parenthesis expected
21205 List of parameters in parenthesis expected
21206 Wrong number of parameters
21207 Unexpected characters at end of line
21208 Assign operator ’:=’ expected
21209 Expression after assign operator ’:=’ expected
21210 Expression in brackets ’[ ]’ for the insert index expected
21211 In for statement, after keyword ’by’ expression for parameter ’Step’ expected
21212 In for statement, after keyword ’to’ expression for parameter ’End’ expected
21213 In for statement, after assign operation (’:=’) expression for parameter ’Start’ expected
21214 In for statement, after ’for .. := .. to ..’ keyword ’by’ expected
21215 In for statement, after ’for .. := ..’ keyword ’to’ expected
21216 In for statement, assign operation ’:=’ for initializing the index variable expected
21217 After ’for’ keyword, assignment of ’Index’ parameter expected
21218 In for statement, error after ’by’ keyword in expression of parameter ’Step’
21219 In for statement, error after ’to’ keyword in expression of parameter ’End’ or the following ’by’ keyword
21220 In for statement, error after assignment operation (’:=’) in expression of parameter ’Start’ or the following ’to’ keyword
21221 In for statement, invalid variable name in parameter ’Index’ or error in the following assignment operation (’:=’)
21222 for statement not complete
21223 In for statement, space after ’for’ expected
21224 In for statement, space after ’to’ expected
21225 In for statement, space after ’by’ expected
21226 Unknown operator or procedure
22000 Internal operation in expression failed
22010 Parameters are tuples with different size
22011 Division by zero
22012 String exceeds maximum length
22100 Parameter is an empty tuple
22101 Parameter has more than one single value
22102 Parameter is not a single value
22103 Parameter has the wrong number of elements
22104 Parameter contains undefined value(s)
22105 Parameter contains wrong value(s)
22106 Parameter contains value(s) with the wrong type
22200 First parameter is an empty tuple
22201 First parameter has more than one single value
22202 First parameter is not a single value
22203 First parameter has the wrong number of elements
22204 First parameter contains undefined value(s)
22205 First parameter contains wrong value(s)
22206 First parameter contains value(s) with the wrong type
22300 Second parameter is an empty tuple
22301 Second parameter has more than one single value
22302 Second parameter is not a single value
22303 Second parameter has the wrong number of elements
22304 Second parameter contains undefined value(s)
22305 Second parameter contains wrong value(s)
22306 Second parameter contains value(s) with the wrong type
30000 User defined exception
7.10 HDevelop Error Codes 247
248 HDevelop Language
Code Export 249
Chapter 8
Code Export
The idea of code export or code generation is as follows: After developing a program according to the given requirements it has to be translated into its final environment. For this, the program is transferred into another programming language that can be compiled.
HDevelop allows to export a developed HDevelop program to the programming languages C++, Visual
Basic, Visual Basic .NET, C#, and C by writing the corresponding code to a file. The following sections describe the general steps of program development using this feature for the languages
• C# - HALCON/.NET ( section 8.2
on page
• C# - HALCON/COM ( section 8.3
on page
• Visual Basic .NET - HALCON/.NET ( section 8.4
on page
• Visual Basic .NET - HALCON/COM ( section 8.5
on page
• Visual Basic 6 - HALCON/COM ( section 8.6
on page
on page
including some language-specific details of the code generation and optimization aspects.
Because HDevelop does more than just execute a HALCON program, the behavior of an exported program will differ in some points from its HDevelop counterpart. A prominent example is that in HDevelop, all results are automatically displayed, while in the exported programs you have to insert the corresponding display operators explicitly.
on page
describes these differences in more detail.
8.1
Code Generation for C++
This section describes how to create a HALCON application in C++, starting from a program developed in HDevelop.
250 Code Export
8.1.1
Basic Steps
8.1.1.1
Program Export
The first step is to export the program using the menu File . Export.... Here, select the language
(C++ - HALCON/C++) and save it to a file. A file will be created that contains the HDevelop program as
C++ source code. For every HDevelop procedure except the main procedure, the exported file contains a C++ procedure with the corresponding name. Iconic input and output parameters of a procedure are declared as Hobject and Hobject*, respectively, while control input and output parameters are declared as HTuple and HTuple*, respectively. All procedures are declared at the beginning of the file.
The program body of the HDevelop main procedure is contained in a procedure action() which is called in the function main(). action() and main() can be excluded from compilation by inserting the instruction #define NO_EXPORT_MAIN at the appropriate position in the application. Using the instruction #define NO_EXPORT_APP_MAIN only the main() procedure is excluded from compilation.
This can be useful if you want to integrate exported HDevelop code into your application through specific procedure interfaces. In that case, there is typically no need to export the main procedure, which was probably used only for testing the functionality implemented in the corresponding ’real’ procedures.
Besides the program code, the file contains all necessary #include instructions. All local variables
(iconic as well as control) are declared in the corresponding procedures. Iconic variables belong to the class Hobject and all other variables belong to HTuple.
8.1.1.2
Compiling and Linking in Windows Environments
The next step is to compile and link this new program. In the Windows environment, Visual C++ is used for the compiling and linking. Example projects can be found in the directory %HALCONROOT%\ examples\cpp.
If you want to use HALCON XL, you have to include the libraries halconxl.lib/.dll and halconcppxl.lib/.dll instead of halcon.lib/.dll and halconcpp.lib/.dll in your project
(see the Programmer’s Guide, chapter 7 on page 71 , for more details).
8.1.1.3
Compiling and Linking in UNIX Environments
To compile and link the new program (called, e.g., test.cpp) under UNIX, you can use the example makefile, which can be found in the directory $HALCONROOT/examples/cpp , by calling make PROG=test
Alternatively, you can set the variable PROG in makefile to test and then just type make.
You can link the program to the HALCON XL libraries by calling make PROG=test XL=1 or just type make XL=1 if you set the variable PROG as described above.
For more details see the Programmer’s Guide, chapter 7 on page 71 .
8.1.2 Optimization
8.1.2
Optimization
Optimization might be necessary for variables of class HTuple. This kind of optimization can either be done in HDevelop or in the generated C++ code. In most cases optimization is not necessary if you program according to the following rules.
1. Using the tuple concatenation, it is more efficient to extend a tuple at the “right” side, like:
T := [T,New] because this can be transformed to
T.Append(New); in C++ and requires no creation of a new tuple, whereas
T := [New,T] which is translated into
T = New.Append(T); would need the creation of a new tuple.
2. Another good way to modify a tuple is the operator insert (see
on page
this case HDevelop code like
T[i] := New can directly be translated into the efficient and similar looking code
T[i] = New;
251
8.1.3
Used Classes
There are only two classes that are used: HTuple for control parameters and Hobject for iconic data.
There is no need for other classes as long as the program has the same functionality as in HDevelop.
When editing a generated program you are free to use any of the classes of HALCON/C++ to extend the functionality.
8.1.4
Limitations and Troubleshooting
Besides the restrictions mentioned in this section and in
on page
description of the HDevelop operators in
on page
252 Code Export
8.1.4.1
Exception Handling
In HDevelop, every exception normally causes the program to stop and report an error message in a dialog window. This might not be useful in C++. In addition, there are different default behaviors concerning the result state of operators.
Messages
In HALCON/C++ only severe errors cause an exception handling which terminates the program and prints an error message. This might cause problems with minor errors, so called messages in HALCON.
These messages are handled as return values of the operators and can have the following values, which are also available in HDevelop as constants:
H_MSG_TRUE
H_MSG_FALSE
H_MSG_FAIL
H_MSG_VOID
One of these messages is always returned indicating the status of the operator. Normally, the result is
H_MSG_TRUE. Some operators return H_MSG_FAIL like read_image or read_region to indicate that they could not open a file or there was no permission to read it. In this case the programmer has to check the return value and apply some adequate action. If the message H_MSG_FALSE is ignored, errors like
Halcon Error #4056: Image data management: object-ID is NULL will happen in successive operators, because the predecessor operator did not calculate an appropriate value.
Errors
In the case of hard errors (i.e., no message as described above) the program stops with an error message.
To prevent this behavior the HDevelop operators dev_error_var and dev_set_check can be used to control the exception handling in the application. This works similarly in HDevelop and C++. One difference is caused by the dynamic evaluation of dev_error_var in HDevelop. This means that each time the operator is executed (e.g., in a loop) the use of the error variable might change. In contrast to this, in C++ special code is added to store the return values of operators. This code will therefore be static and cannot change during program execution. To understand how the code generation works let us have a look at a short example. Here at first the HDevelop program: dev_set_check(
'~give_error') dev_error_var(error,true) threshold(image,region,100,255) dev_error_var(error,false) if (error # H_MSG_TRUE) write_string(WindowId,
'error number = ' + error) exit() endif dev_set_check(
'give_error')
8.2 Code Generation for C# (HALCON/.NET) 253
This program will be translated into
HTuple error; set_check("~give_error"); error = threshold(image,®ion,100,255); if (error != 2)
{ write_string(WindowId,HTuple("error number = ") + HTuple(error)); exit(1);
} set_check("give_error");
As can be seen, the operator dev_error_var is eliminated and replaced by the use of the error variable later on.
The points mentioned above might cause these two problems:
• If the second parameter of dev_error_var cannot be derived from the program (because no constant false or true are used but expressions, the value will be interpreted as true, that means:
“start to use the variable”. To avoid confusion use only the constants false or true as values for the second parameter.
• The usage of a variable starts after the first call of dev_error_var(ErrVariable,true).
In C++ this means that all successive lines (i.e., lines “below”), until the first dev_error_var(ErrVariable,false) will have the assignment to ErrVariable. This might lead to a different behavior compared with HDevelop, if dev_error_var is called inside a loop, because here the operators inside the loop before dev_error_var might also use ErrVariable after the second execution of the loop body. Therefore: Try not to use dev_error_var inside a loop. Use it right at the beginning of the program.
8.2
Code Generation for C# (HALCON/.NET)
This section describes how to create a HALCON application in C#, starting from a program developed in HDevelop. HALCON can be used together with C# based on the .NET interface of HALCON. A detailed description of this interface can be found in the Programmer’s Guide, part III on page 83 .
8.2.1
Basic Steps
8.2.1.1
Export
The first step is to export the program using the menu File . Export.... Here, select the language
(C# - HALCON/.NET) and save it to file. The result is a new file with the given name and the extension
“.cs”.
254 Code Export
8.2.1.2
The C# Template
If the file has been exported using the option Use Export Template, it is intended to be used together with the predefined C# project that can be found in the directory
%HALCONROOT%\examples\c#\HDevelopTemplate
This project contains a form with a display window (HWindowControl) and a button labeled Run. Add the file generated by HDevelop to the project in the Solution Explorer (Add Existing Item). Now the project is ready for execution: Run the project and then press the button Run on the form, which will call the exported code.
Additional information about using the template can be found in the Programmer’s Guide, section 11.4.1
on page 114 .
8.2.2
Program Structure
If the program has been exported using the option Use Export Template, the file created by HDevelop contains a subroutine with the corresponding name for every HDevelop procedure except the main procedure, which is contained in the subroutine action(). Otherwise, the file is exported as a standalone application. Iconic input and output parameters of a procedure are passed as HObject and out HObject, respectively, while control input and output parameters are passed as HTuple and out
HTuple, respectively. The subroutine RunHalcon() contains a call to the subroutine action() and has a parameter Window, which is of type HTuple. This is the link to the window on the form to which all output operations are passed. In addition, another subroutine is created with the name InitHalcon().
This subroutine applies the same initializations that HDevelop performs.
Most of the variables (iconic as well as control) are declared locally inside the corresponding subroutines.
Iconic variables belong to the class HObject and control variables belong to HTuple.
Depending on the program, additional subroutines and variables are declared.
8.2.2.1
Stop
The HDevelop operator stop is translated into a subroutine in C# that creates a message box. This message box causes the program to halt until the button is pressed.
8.2.2.2
Used Classes
There are only four classes/types that are used: HTuple for control parameters and HObject for iconic data. In addition, there is the class HWindowControl. It is used inside the project for the output window and a variable of class HTuple directs the output to this window. Finally, the class HOperatorSet is used as a container for all HALCON operators. There is no need for other classes as long as the program has the same functionality as in HDevelop. When editing a generated program you are free to use any of the classes of HALCON/.NET to extend the functionality.
8.2.3 Limitations and Troubleshooting
8.2.3
Limitations and Troubleshooting
Besides the restrictions mentioned in this section and in
on page
description of the HDevelop operators in
on page
8.2.3.1
Variable Names
The export adds the prefix ho_ to all local iconic and hv_ to all local control variables, respectively, in order to avoid collisions with reserved words.
8.2.3.2
Exception Handling
In HDevelop, every exception normally causes the program to stop and report an error message in a dialog window. This might not be useful in C#. The standard way to handle this in C# is by using the try/catch mechanism. This allows to access the reason for the exception and to continue accordingly.
Thus, for HDevelop programs containing error handling ((dev_)set_check("˜give_error")) the corresponding code is automatically included. Every operator call, for which it is assumed that the
HALCON error mechanism is turned off, is enclosed in a try block followed by a catch block. The latter handles the exception and assigns the corresponding HALCON error number to the error variable activated by dev_error_var or to a local error variable, otherwise.
Please note that a call of (dev_)set_check("˜give_error") has no influence on the operator call.
The exception will always be raised. This is also true for messages like H_MSG_FAIL, which are not handled as exceptions in C++, for example.
8.2.3.3
Memory Management
The .NET Framework’s runtime environment CLR (Common Language Runtime) has a mechanism called garbage collector, which is used by the CLR to remove no longer needed .NET objects from memory. As mentioned earlier, in the exported C# code every iconic object is represented by a .NET
HObject object. From the garbage collector’s point of view, a .NET HObject object is rather small.
Thus, it might not be collected from memory although the underlying iconic object (e.g., an image) might in fact occupy a large portion of memory. In order to avoid memory leaks caused by this effect, in the exported code every iconic object is deleted explicitly before it is assigned a new value.
255
8.3
Code Generation for C# (HALCON/COM)
This section describes how to create a HALCON application in C#, starting from a program developed in HDevelop. HALCON can be used together with C# based on the COM interface of HALCON. A detailed description of this interface can be found in the Programmer’s Guide, part IV on page 121 .
Note that this export is only provided for backwards compatibility. We recommend to use the export based on HALCON/.NET (see
on page
256 Code Export
8.3.1
Basic Steps
8.3.1.1
Export
The first step is to export the program using the menu File . Export.... Here, select the language (C#
- HALCON/COM) and save it to file. The result is a new file with the given name and the extension “.cs”.
8.3.1.2
The C# Template
If the file has been exported using the option Use Export Template, it is intended to be used together with the predefined C# project that can be found in the directory
%HALCONROOT%\examples\c#\HDevelopTemplateCOM
This project contains a form with a display window (HWindowXCtrl) and a button labeled Run. Add the file generated by HDevelop to the project in the Solution Explorer (Add Existing Item). Now the project is ready for execution: Run the project and then press the button Run on the form, which will call the exported code.
8.3.2
Program Structure
If the program has been exported using the option Use Export Template, the file created by HDevelop contains a subroutine with the corresponding name for every HDevelop procedure except the main procedure, which is contained in the subroutine action(). Otherwise, the file is exported as a standalone application. Iconic input and output parameters of a procedure are passed as HUntypedObjectX and out
HUntypedObjectX, respectively, while control input and output parameters are passed as object and out object, respectively. The subroutine RunHalcon() contains a call to the subroutine action() and has a parameter Window, which is of type HWindowX. This is the link to the window on the form to which all output operations are passed. In addition, another subroutine is created with the name
InitHalcon(). This subroutine applies the same initializations that HDevelop performs.
Most of the variables (iconic as well as control) are declared locally inside the corresponding subroutines.
Iconic variables belong to the class HUntypedObjectX and control variables belong to object.
Depending on the program, additional subroutines and variables are declared.
8.3.2.1
Arrays
If a single value is inserted into an object array, a special subroutine is called to ensure that the array is valid. If the array is too small or of the wrong type, it is recreated in the appropriate way.
8.3.3 Limitations and Troubleshooting 257
8.3.2.2
Expressions
All parameter expressions inside HDevelop are translated into expressions based on the HALCON tuple operators. Therefore, an expression might look somewhat complex. In many cases these expressions can be changed to simple C# expressions. For example, TupleSub becomes a simple subtraction. To ensure that the exported program has the same effect in C#, this exchange is not applied automatically because the semantics are not always identical.
8.3.2.3
Used Classes
There are only six classes/types that are used: object for control parameters and HUntypedObjectX for iconic data. In addition, there is the container class HTupleX, which comprises all operators of HALCON processing tuples, in this case the data type object. Then, there are the classes HWindowXCtrl and its low-level content HWindowX. HWindowXCtrl is used inside the project for the output window and a variable of class HWindowX directs the output to this window. Finally, the class HOperatorSetX is used as a container for all HALCON operators. There is no need for other classes as long as the program has the same functionality as in HDevelop. When editing a generated program you are free to use any of the classes of HALCON/COM to extend the functionality.
8.3.3
Limitations and Troubleshooting
Besides the restrictions mentioned in this section and in
on page
description of the HDevelop operators in
on page
8.3.3.1
Variable Names
The export adds the prefix ho_ to all local iconic and hv_ to all local control variables, respectively, in order to avoid collisions with reserved words.
8.3.3.2
Exception Handling
In HDevelop, every exception normally causes the program to stop and report an error message in a dialog window. This might not be useful in C#. The standard way to handle this in C# is by using the try/catch mechanism. This allows to access the reason for the exception and to continue accordingly.
Thus, for HDevelop programs containing error handling ((dev_)set_check("˜give_error")) the corresponding code is automatically included. Every operator call, for which it is assumed that the
HALCON error mechanism is turned off, is enclosed in a try block followed by a catch block. The latter handles the exception and assigns the corresponding HALCON error number to the error variable activated by dev_error_var or to a local error variable, otherwise.
Please note that a call of (dev_)set_check("˜give_error") has no influence on the operator call.
The exception will always be raised. This is also true for messages like H_MSG_FAIL, which are not handled as exceptions in C++, for example.
258 Code Export
When handling exceptions you also have to be aware that the COM interface always resets the output parameters at the beginning of the operator execution. Thus, when the exception occurs, output variables are set to Nothing. Therefore, you cannot use the values of variables used as output parameters of the operator causing the exception.
8.3.3.3
Memory Management
The .NET Framework’s runtime environment CLR (Common Language Runtime) has a mechanism called garbage collector, which is used by the CLR to remove no longer needed .NET objects from memory. As mentioned earlier, in the exported C# code every iconic object is represented by a .NET
HUntypedObjectX object, which contains a reference to a COM HUntypedObjectX object. From the garbage collector’s point of view, a .NET HUntypedObjectX object is rather small. Thus, it might not be collected from memory although the underlying iconic object (e.g., an image) might in fact occupy a large portion of memory. In order to avoid memory leaks caused by this effect, in the exported code every iconic object is deleted explicitly before it is assigned a new value.
8.4
Code Generation for Visual Basic .NET (HALCON/.NET)
This section describes how to create a HALCON application in Visual Basic .NET, starting from a program developed in HDevelop. HALCON can be used together with Visual Basic .NET based on the
.NET interface of HALCON. A detailed description of this interface can be found in the Programmer’s
Guide, part III on page 83 .
8.4.1
Basic Steps
8.4.1.1
Export
The first step is to export the program using the menu File . Export.... Here, select the language
(Visual Basic .NET - HALCON/.NET) and save it to file. The result is a new file with the given name and the extension “.vb”.
8.4.1.2
The Visual Basic .NET Template
If the file has been exported using the option Use Export Template, it is intended to be used together with the predefined Visual Basic .NET project that can be found in the directory
%HALCONROOT%\examples\vb.net\HDevelopTemplate
This project contains a form with a display window (HWindowControl) and a button labeled Run. Add the file generated by HDevelop to the project in the Solution Explorer (Add Existing Item). Now the project is ready for execution: Run the project and then press the button Run on the form, which will call the exported code.
Additional information about using the template can be found in the Programmer’s Guide, section 11.4.1
on page 114 .
8.4.2 Program Structure
8.4.2
Program Structure
If the program has been exported using the option Use Export Template, the file created by HDevelop contains a subroutine with the corresponding name for every HDevelop procedure except the main procedure, which is contained in the subroutine action(). Otherwise, the file is exported as a standalone application. Iconic input and output parameters of a procedure are passed as ByVal HObject and ByRef
HObject, respectively, while control input and output parameters are passed as ByVal HTuple and
ByRef HTuple, respectively. The subroutine RunHalcon() contains a call to the subroutine action() and has a parameter Window, which is of type HTuple. This is the link to the window on the form to which all output operations are passed. In addition, another subroutine is created with the name
InitHalcon(). This subroutine applies the same initializations that HDevelop performs.
Most of the variables (iconic as well as control) are declared locally inside the corresponding subroutines.
Iconic variables belong to the class HObject and control variables belong to HTuple.
Depending on the program, additional subroutines and variables are declared.
8.4.2.1
Stop
The HDevelop operator stop is translated into a subroutine in Visual Basic .NET that creates a message box. This message box causes the program to halt until the button is pressed.
8.4.2.2
Exit
The HDevelop operator exit is translated into the Visual Basic .NET routine End. Because this routine has no parameter, the parameters of exit are suppressed.
8.4.2.3
Used Classes
There are only four classes/types that are used: HTuple for control parameters and HObject for iconic data. In addition, there is the class HWindowControl. It is used inside the project for the output window and a variable of class HTuple directs the output to this window. Finally, the class HOperatorSet is used as a container for all HALCON operators. There is no need for other classes as long as the program has the same functionality as in HDevelop. When editing a generated program you are free to use any of the classes of HALCON/.NET to extend the functionality.
8.4.3
Limitations and Troubleshooting
Besides the restrictions mentioned in this section and in
on page
description of the HDevelop operators in
on page
8.4.3.1
Variable Names
In contrast to C, C++, or HDevelop, Visual Basic .NET has many reserved words. Thus, the export adds the prefix ho_ to all iconic and hv_ to all control variables, respectively, in order to avoid collisions with these reserved words. See also
on page
about case sensitivity.
259
260 Code Export
8.4.3.2
Exception Handling
In HDevelop, every exception normally causes the program to stop and report an error message in a dialog window. This might not be useful in Visual Basic .NET. The standard way to handle this in Visual Basic .NET is by using the Try/Catch mechanism. This allows to access the reason for the exception and to continue accordingly. Thus, for HDevelop programs containing error handling
((dev_)set_check("˜give_error")) the corresponding code is automatically included. Every operator call, for which it is assumed that the HALCON error mechanism is turned off, is enclosed in a
Try block followed by a Catch block. The latter handles the exception and assigns the corresponding
HALCON error number to the error variable activated by dev_error_var or to a local error variable, otherwise.
Please note that a call of (dev_)set_check("˜give_error") has no influence on the operator call.
The exception will always be raised. This is also true for messages like H_MSG_FAIL, which are not handled as exceptions in C++, for example.
8.4.3.3
Memory Management
The .NET Framework’s runtime environment CLR (Common Language Runtime) has a mechanism called garbage collector, which is used by the CLR to remove no longer needed .NET objects from memory. As mentioned earlier, in the exported Visual Basic .NET code every iconic object is represented by a .NET HObject object. From the garbage collector’s point of view, a .NET HObject object is rather small. Thus, it might not be collected from memory although the underlying iconic object (e.g., an image) might in fact occupy a large portion of memory. In order to avoid memory leaks caused by this effect, in the exported code every iconic object is deleted explicitly before it is assigned a new value.
8.5
Code Generation for Visual Basic .NET (HALCON/COM)
This section describes how to create a HALCON application in Visual Basic .NET, starting from a program developed in HDevelop. HALCON can be used together with Visual Basic .NET based on the
COM interface of HALCON. A detailed description of this interface can be found in the Programmer’s
Guide, part IV on page 121 .
Note that this export is only provided for backwards compatibility. We recommend to use the export based on HALCON/.NET (see
on page
8.5.1
Basic Steps
8.5.1.1
Export
The first step is to export the program using the menu File . Export.... Here, select the language
(Visual Basic .NET - HALCON/COM) and save it to file. The result is a new file with the given name and the extension “.vb”.
8.5.2 Program Structure 261
8.5.1.2
The Visual Basic .NET Template
If the file has been exported using the option Use Export Template, it is intended to be used together with the predefined Visual Basic .NET project that can be found in the directory
%HALCONROOT%\examples\vb.net\HDevelopTemplateCOM
This project contains a form with a display window (HWindowXCtrl) and a button labeled Run. Add the file generated by HDevelop to the project in the Solution Explorer (Add Existing Item). Now the project is ready for execution: Run the project and then press the button Run on the form, which will call the exported code.
8.5.2
Program Structure
If the program has been exported using the option Use Export Template, the file created by HDevelop contains a subroutine with the corresponding name for every HDevelop procedure except the main procedure, which is contained in the subroutine action(). Otherwise, the file is exported as a standalone application. Iconic input and output parameters of a procedure are passed as ByVal HUntypedObjectX and ByRef HUntypedObjectX, respectively, while control input and output parameters are passed as
ByVal Object and ByRef Object, respectively. The subroutine RunHalcon() contains a call to the subroutine action() and has a parameter Window, which is of type HWindowX. This is the link to the window on the form to which all output operations are passed. In addition, another subroutine is created with the name InitHalcon(). This subroutine applies the same initializations that HDevelop performs.
Most of the variables (iconic as well as control) are declared locally inside the corresponding subroutines.
Iconic variables belong to the class HUntypedObjectX and control variables belong to Object.
Depending on the program, additional subroutines and variables are declared.
8.5.2.1
Arrays
If a single value is inserted into an Object array, a special subroutine is called to ensure that the array is valid. If the array is too small or of the wrong type, it is recreated in the appropriate way.
8.5.2.2
Expressions
All parameter expressions inside HDevelop are translated into expressions based on the HALCON tuple operators. Therefore, an expression might look somewhat complex. In many cases these expressions can be changed to simple Visual Basic .NET expressions. For example, TupleSub becomes a simple subtraction. To ensure that the exported program has the same effect in Visual Basic .NET, this exchange is not applied automatically because the semantics are not always identical.
8.5.2.3
Stop
The HDevelop operator stop is translated into a subroutine in Visual Basic .NET that creates a message box. This message box causes the program to halt until the button is pressed.
262 Code Export
8.5.2.4
Exit
The HDevelop operator exit is translated into the Visual Basic .NET routine End. Because this routine has no parameter, the parameters of exit are suppressed.
8.5.2.5
Used Classes
There are only six classes/types that are used: Object for control parameters and HUntypedObjectX for iconic data. In addition, there is the container class HTupleX, which comprises all operators of HALCON processing tuples, in this case the data type Object. Then, there are the classes HWindowXCtrl and its low-level content HWindowX. HWindowXCtrl is used inside the project for the output window and a variable of class HWindowX directs the output to this window. Finally, the class HOperatorSetX is used as a container for all HALCON operators. There is no need for other classes as long as the program has the same functionality as in HDevelop. When editing a generated program you are free to use any of the classes of HALCON/COM to extend the functionality.
8.5.3
Limitations and Troubleshooting
Besides the restrictions mentioned in this section and in
on page
description of the HDevelop operators in
on page
8.5.3.1
Variable Names
In contrast to C, C++, or HDevelop, Visual Basic .NET has many reserved words. Thus, the export adds the prefix ho_ to all iconic and hv_ to all control variables, respectively, in order to avoid collisions with these reserved words.
8.5.3.2
Exception Handling
In HDevelop, every exception normally causes the program to stop and report an error message in a dialog window. This might not be useful in Visual Basic .NET. The standard way to handle this in Visual Basic .NET is by using the Try/Catch mechanism. This allows to access the reason for the exception and to continue accordingly. Thus, for HDevelop programs containing error handling
((dev_)set_check("˜give_error")) the corresponding code is automatically included. Every operator call, for which it is assumed that the HALCON error mechanism is turned off, is enclosed in a
Try block followed by a Catch block. The latter handles the exception and assigns the corresponding
HALCON error number to the error variable activated by dev_error_var or to a local error variable, otherwise.
Please note that a call of (dev_)set_check("˜give_error") has no influence on the operator call.
The exception will always be raised. This is also true for messages like H_MSG_FAIL, which are not handled as exceptions in C++, for example.
When handling exceptions you also have to be aware that the COM interface always resets the output parameters at the beginning of the operator execution. Thus, when the exception occurs, output variables are set to Nothing. Therefore, you cannot use the values of variables used as output parameters of the operator causing the exception.
8.6 Code Generation for Visual Basic 6 (HALCON/COM) 263
8.5.3.3
Memory Management
The .NET Framework’s runtime environment CLR (Common Language Runtime) has a mechanism called garbage collector, which is used by the CLR to remove no longer needed .NET objects from memory. As mentioned earlier, in the exported Visual Basic .NET code every iconic object is represented by a .NET HUntypedObjectX object, which contains a reference to a COM HUntypedObjectX object.
From the garbage collector’s point of view, a .NET HUntypedObjectX object is rather small. Thus, it might not be collected from memory although the underlying iconic object (e.g., an image) might in fact occupy a large portion of memory. In order to avoid memory leaks caused by this effect, in the exported code every iconic object is deleted explicitly before it is assigned a new value.
8.6
Code Generation for Visual Basic 6 (HALCON/COM)
This section describes how to create a HALCON application in Visual Basic 6, starting from a program developed in HDevelop. HALCON can be used together with Visual Basic 6 based on the COM interface of HALCON. A detailed description of this interface can be found in the Programmer’s Guide, part IV on page 121 .
8.6.1
Basic Steps
8.6.1.1
Export
The first step is to export the program using the menu File . Export.... Here, select the language
(Visual Basic 6.0 - HALCON/COM) and save it to file. The result is a new file with the given name and the extension “.bas”.
8.6.1.2
The Visual Basic 6 Template
If the file has been exported using the option Use Export Template, it is intended to be used together with the predefined Visual Basic 6 project that can be found in the directory
%HALCONROOT%\examples\vb\HDevelopTemplate
This project contains a form with a display window (HWindowXCtrl) and a button labeled Run. The file generated by HDevelop has to be added to this project. This is done by using the menu Project . Add
Module . Existing and selecting the file. Now the project is ready for execution: Run the project and then press the button Run on the form, which will call the exported code.
8.6.2
Program Structure
If the program has been exported using the option Use Export Template, the file created by HDevelop contains a subroutine with the corresponding name for every HDevelop procedure except the main procedure, which is contained in the subroutine action(). Otherwise, the file is exported as a standalone
264 Code Export
application. Iconic input and output parameters of a procedure are passed as ByVal HUntypedObjectX and ByRef HUntypedObjectX, respectively, while control input and output parameters are passed as
ByVal Variant and ByRef Variant, respectively. The subroutine RunHalcon() contains a call to the subroutine action() and has a parameter Window, which is of type HWindowX. This is the link to the window on the form to which all output operations are passed. In addition, another subroutine is created with the name InitHalcon(). This subroutine applies the same initializations that HDevelop performs.
Most of the variables (iconic as well as control) are declared locally inside the corresponding subroutines.
Iconic variables belong to the class HUntypedObjectX and control variables belong to Variant. The subroutine RunHalcon() has a parameter Window, which is of type HWindowX. This is the link to the window in the panel to which all output operations are passed.
Depending on the program, additional subroutines and variables are declared.
8.6.2.1
Arrays
If a single value is inserted into a Variant array, a special subroutine is called to ensure that the index is valid. If the array is too small it is resized.
8.6.2.2
Expressions
All parameter expressions inside HDevelop are translated into expressions based on the HALCON tuple operators. Therefore, an expression might look somewhat complex. In many cases these expressions can be changed to simple Visual Basic expressions. For example, TupleSub becomes a simple subtraction.
To ensure that the exported program has the same effect in Visual Basic, this exchange is not applied automatically because the semantics are not always identical.
8.6.2.3
Stop
The HDevelop operator stop is translated into a subroutine in Visual Basic that creates a message box.
This message box causes the program to halt until the button is pressed.
8.6.2.4
Exit
The HDevelop operator exit is translated into the Visual Basic routine End. Because this routine has no parameter, the parameters of exit are suppressed.
8.6.2.5
Used Classes
There are only six classes/types that are used: Variant for control parameters and HUntypedObjectX for iconic data. In addition, there is the container class HTupleX, which comprises all operators of HAL-
CON processing tuples, in this case the data type Variant. Then, there are the classes HWindowXCtrl and its low-level content HWindowX. HWindowXCtrl is used inside the project for the output window
8.6.3 Limitations and Troubleshooting 265
and a variable of class HWindowX directs the output to this window. Finally, the class HOperatorSetX is used as a container for all HALCON operators. There is no need for other classes as long as the program has the same functionality as in HDevelop. When editing a generated program you are free to use any of the classes of HALCON/COM to extend the functionality.
8.6.3
Limitations and Troubleshooting
Besides the restrictions mentioned in this section and in
on page
description of the HDevelop operators in
on page
8.6.3.1
Variable Names
In contrast to C, C++, or HDevelop, Visual Basic has many reserved words. Thus, the export adds the prefix ho_ to all iconic and hv_ to all control variables, respectively, in order to avoid collisions with these reserved words.
8.6.3.2
Exception Handling
In HDevelop, every exception normally causes the program to stop and report an error message in a dialog window. This might not be useful in Visual Basic. The standard way to handle this in Visual
Basic is by using the On Error Goto command. This allows to access the reason for the exception and to continue accordingly. Thus, for HDevelop programs containing error handling (dev_error_var) the corresponding code is automatically included.
Please note that a call of (dev_)set_check("˜give_error") has no influence on the operator call.
The exception will always be raised. This is also true for messages like H_MSG_FAIL, which are not handled as exceptions in C++, for example.
When handling exceptions you also have to be aware that the COM interface always resets the output parameters at the beginning of the operator execution. Thus, when the exception occurs, output variables are set to Nothing. Therefore, you cannot use the values of variables used as output parameters of the operator causing the exception.
8.7
Code Generation for C
This section describes how to create a HALCON application in C, starting from a program developed in
HDevelop.
8.7.1
Basic Steps
8.7.1.1
Program Export
The first step is to export the program using the menu File . Export.... Here, select the language
(C - HALCON/C) and save it to file. A file will be created that contains the HDevelop program as C
266 Code Export
source code. For every HDevelop procedure except the main procedure, the exported file contains a
C procedure with the corresponding name. Iconic input and output parameters of a procedure are declared as Hobject and Hobject*, respectively, while control input and output parameters are declared as Htuple and Htuple*, respectively. All procedures are declared at the beginning of the file. The program body of the HDevelop main procedure is contained in a procedure action() which is called in function main(). action() and main() can be excluded from compilation by inserting the instruction #define NO_EXPORT_MAIN at the appropriate position in the application. Using the instruction
#define NO_EXPORT_APP_MAIN only the main() procedure is excluded from compilation. This can be useful if you want to integrate exported HDevelop code into your application through specific procedure interfaces. In that case, there is typically no need to export the main procedure, which was probably used only for testing the functionality implemented in the corresponding ’real’ procedures.
Besides the program code, the file contains all necessary #include instructions. All local variables
(iconic as well as control) are declared in the corresponding procedures. Iconic variables belong to the class Hobject and all other variables belong to Htuple.
Please note that in the current version the generated C code is not optimized for readability. It is output such that it always produces identical results as the HDevelop code.
8.7.1.2
Compiling and Linking in Windows Environments
The next step is to compile and link this new program. In the Windows environment, Visual C++ is used for the compiling and linking. Example projects can be found in the directory %HALCONROOT%\ examples\c.
If you want to use HALCON, you have to include the libraries halconxl.lib/.dll and halconcxl.lib/.dll instead of halcon.lib/.dll and halconc.lib/.dll in your project (see the
Programmer’s Guide, chapter 18 on page 159 , for more details).
8.7.1.3
Compiling and Linking in UNIX Environments
To compile and link the new program (called, e.g., test.c) under UNIX, you can use the example makefile, which can be found in the directory $HALCONROOT/examples/c , by calling make TEST_PROG=test
Alternatively, you can set the variable TEST_PROG in makefile to test and then just type make.
You can link the program to the HALCON XL libraries by calling make TEST_PROG=test XL=1 or just type make XL=1 if you set the variable TEST_PROG as described above.
For more details see the Programmer’s Guide, chapter 18 on page 159 .
8.8 General Aspects of Code Generation
8.8
General Aspects of Code Generation
In the following, general differences in the behavior of a HDevelop program and its exported versions are described.
8.8.1
User-Defined Code Blocks
HDevelop comments containing the # symbol as the first character are exported as plain text statements.
For example, the line
* #Call MsgBox("Press button to continue",vbYes,"Program stop","",1000) in HDevelop will result in
Call MsgBox("Press button to continue",vbYes,"Program stop","",1000) in Visual Basic 6. This feature can be used to integrate Visual Basic, Visual Basic .NET, C#, C++, or
C code into a HDevelop program. Furthermore, some additional special comments are recognized to specify the destination of the plain text statements. For example, the line
* #^^#define NO_EXPORT_APP_MAIN puts the given text at the very beginning of the exported program. Comments in this format are collected from the main procedure first, followed by #^^ comments in other procedures.
The recognized special comments are summarized in
8.8.2
Assignment
In HDevelop each time a new value is assigned to a variable its old contents are removed automatically, independent of the type of the variable. In the exported code, this is also the case for iconic objects
Prefix Where the text following the prefix goes in the exported program
#
#ˆˆ
#$$
#ˆ
#$
The place of insertion
Beginning of the program
End of the program
Before the current procedure
After the current procedure
Table 8.1: Special comments in HDevelop.
267
268 Code Export
(HALCON/C++: Hobject, HALCON/.NET: HObject, HALCON/COM: HUntypedObjectX) and for the class HTuple (HALCON/C++, HALCON/.NET), the type Variant (Visual Basic 6), and the class object (HALCON/COM for .NET languages), as they all have a destructor that removes the stored data. Because C does not provide destructors, the generated C code calls the operators clear_obj and destroy_tuple to remove the content of iconic output parameters (Hobject) and control output parameters (Htuple) before each operator call. Memory issues regarding iconic objects in HALCON/.NET
are described in
(Visual Basic .NET) and
(C#). Memory issues regarding iconic objects in HALCON/COM are described in
(Visual Basic .NET) and
(C#).
However, problems arise if a tuple (variant) contains a handle, for example for a file, a window, or for
OCR. In this case, the memory of the handle is automatically removed but not the data to which it points.
In the exported programs, this data therefore has to be removed explicitly by calling the corresponding operators close_* like close_ocr or close_ocv. Please insert the close_* operators for all handles in use
• before a new value is assigned to a handle and
• at the end of the program.
8.8.3
Variable Names
Variable names in HDevelop are case-sensitive, i.e., x and X are distinct variable names in HDevelop programs. If you export such a program to a case-insensitive target language (e.g., Visual Basic .NET), the development environment will complain about multiple declarations. Either plan ahead and avoid these variable names, or use the Find/Replace dialog to substitute conflicting variable names before exporting your program.
8.8.4
for Loops
HDevelop and the programming languages have different semantics for loops, which may cause confusion. Because the problems are so rare and the generated code would become very difficult to understand otherwise, the code generation ignores the different semantics. These differences are:
1. In the programming languages, you can modify the loop variable (e.g., by setting it to the end value of the condition) to terminate the loop. This can’t be done in HDevelop because here the current value is stored “inside” the for-operator and is automatically updated when it is executed again.
2. In the programming languages, you can modify the step range if you use a variable for the increment. This is also not possible with HDevelop because the increment is stored “inside” the for-operator when the loop is entered.
3. The last difference concerns the value of the loop variable after exiting the loop. In the programming languages, it has the value with which the condition becomes false for the first time. In
HDevelop it contains the end value, which was calculated when the loop was entered.
Looking at the mentioned points, we recommend to program according to the following rules:
8.8.5 Protected External Procedures 269
1. Don’t modify the loop variable or the step value inside the loop. If you need this behavior, use the while-loop.
2. Don’t use the loop variable after the loop.
8.8.5
Protected External Procedures
As described for the different programming languages, HDevelop procedures are exported automatically to procedures or subroutines of the selected programming language. This does not hold for the protected external procedures described in
on page
123 . These procedures are protected by a
password so that they cannot be viewed and modified by unauthorized users. Thus, as long as they are locked by the password, they can not be exported to any programming language.
8.8.6
System Parameters
You should know that HDevelop performs some changes of system parameters of HALCON by calling the operator set_system (see the reference manual). This might cause the exported program not to produce identical output. If such a problem arises, you may query the system parameters by means of get_system in HDevelop after or while running the original HDevelop version of the program.
Depending to the problem, you can now modify relevant parameters by explicitly calling the operator set_system in the exported program.
8.8.7
Graphics Windows
HALCON provides a functionality that emulates the behavior of HDevelop graphics windows for HAL-
CON windows. This HALCON window stack is accessible via class methods and functions in the
HALCON interfaces, and code exported from HDevelop uses this functionality when opening, closing, setting, or accessing the active window. The HALCON window stack mechanism is threadsafe. Thus, in a multithreaded application every thread has its own window stack. In order to avoid memory leaks or similar problems, the application must take care to close all HALCON windows opened by a thread before terminating the thread because this is not done automatically by HALCON.
For the .NET and COM code exports it is optional whether to export HDevelop programs as code using the HDevelop export example templates or as code using the previously described HALCON window stack functionality when doing graphics windows output. Additionally, in the latter case the exported code contains a main function and thus is usable as a standalone application. The HDevelop Export dialog allows to select the corresponding option.
The graphics windows of HDevelop and the basic windows of the HALCON libraries
• HALCON/C++: class HWindow,
• HALCON/.NET: class HWindowControl,
• HALCON/COM: class HWindowXCtrl, and
• HALCON/C: addressed via handles
270 Code Export
have different functionality.
• Multiple windows
If you use the operator dev_open_window to open multiple graphics windows in HDevelop, these calls will be converted into corresponding calls of open_window only if the export option Use
HALCON Windows is selected.
In the export of Visual Basic, Visual Basic .NET, and C# programs using the option Use Export
Template, all window operations are suppressed, because the exported code is intended to work together with the corresponding template. If you want to use more than one window in programs exported in this mode, you have to modify the code and project manually.
Note that the export of programs containing multiple windows using the option Use HALCON
Windows might be incorrect if the active graphics window was changed using the mouse during program execution. It is recommended to use the operator dev_set_window explicitly to achieve the same functionality.
• Window size
In exported Visual Basic, Visual Basic .NET, and C# programs, the size of the window on the form is predefined (512 × 512); thus, it will normally not fit your image size. Therefore, you must adapt the size interactively or by using the properties of the window.
• Displaying results
Normally, the result of every operator is displayed in the graphics window of HDevelop. This is not the case when using an exported program. It behaves like the HDevelop program running with the option: “update window = off”. We recommend to insert the operator dev_display in the HDevelop program at each point where you want to display data. This will not change the behavior of the HDevelop program but result in the appropriate call in the exported code.
When generating code using the option Use HALCON Windows, close the default graphics window
(using dev_close_window
) and open a new one (using dev_open_window
) before the first call of dev_display in order to assure a correct export.
• Displaying images
In HDevelop, images are automatically scaled to fit the current window size. This is not the case in exported programs . For example, if you load and display two images of different size, the second one will appear clipped if it is larger than the first image or filled up with black areas if it is smaller.
For a correct display, you must use the operator dev_set_part before displaying an image with dev_display as follows: dev_set_part (0, 0, ImageHeight-1, ImageWidth-1) dev_display (Image)
In this example, Image is the image variable, ImageHeight and ImageWidth denote its size.
You can query the size of an image with the operator get_image_pointer1
. Please consult the
HALCON Reference Manuals for more details.
Note that the operator dev_set_part
(and its HALCON library equivalent set_part
) is more commonly used for displaying (and thereby zooming) parts of images. By calling it with the full size of an image as shown above, you assure that the image exactly fits the window.
• Changing display parameters
If you change the way how results are displayed (color, line width, etc.) in HDevelop interac-
8.8.7 Graphics Windows 271
tively via the menu Visualization, these changes will not be incorporated in the exported program. We recommend to insert the corresponding Develop operators (e.g., dev_set_color or dev_set_line_width
) in the HDevelop program explicitly. This will result in the appropriate call ( set_color
, set_line_width
, etc.) in the exported code.
272 Code Export
Tips & Tricks 273
Chapter 9
Tips & Tricks
This chapter contains helpful information for working with HDevelop.
9.1
Keycodes
In order to speed up the entering of values in the input fields of HDevelop (e.g., operator parameters), several keycodes are defined, which have special functions. These keyboard mappings are shown in
9.2
Online Help
Online documentation is available in PDF and partly in HTML format.
HDevelop provides an integrated online help window. You can conveniently browse the HTML-based documentation in this window view the HTML files in your web browser. In HDevelop you may call the online help window via the menu Help . Help or by pressing <F1>. The functionality is described in
on page
Besides HTML, the documentation is available in PDF format as well. If you click on a PDF document in the online help window, the registered application for viewing PDF files starts up automatically.
9.3
Warning and Error Windows
Warning and error windows are popups that make the user aware of user errors. Usually, they interrupt the faulty actions with a description of the error. For this purpose information about the kind of the error is determined during the execution.
shows an example of an error window.
274 Tips & Tricks
<Home>
<End>
<Left>
<Right>
<Ctrl> <Left>
<Ctrl> <Right>
<Delete>
Text editing
Move cursor to the beginning of the line.
Move cursor to the end of the line.
Move cursor left one character.
Move cursor right one character.
Move cursor left one word.
Move cursor right one word.
Delete single character to the right of the cursor position.
<Backspace>
<Ctrl> <Backspace>
<Ctrl> <Delete>
<Shift> <Left>
<Ctrl> d
<Ctrl> e
<Ctrl> k
<Ctrl> u
Delete single character to the left of the cursor position.
Delete word to the left of the cursor.
Delete word to the right of the cursor.
Select character to the left of the cursor (or extend the selection by one character).
<Shift> <Right>
Select character to the right of the cursor (or extend the selection by one character).
<Ctrl> <Shift> <Left>
Select word to the left of the cursor (or extend the selection by one word).
<Ctrl> <Shift> <Right>
Select word to the right of the cursor (or extend the selection by one word).
<Ctrl> a
Select all.
UNIX: Analogous to Delete
UNIX: Move cursor to last character in line.
UNIX: Delete all characters from current position to end of line.
UNIX: Delete entire input line.
GUI Navigation
<Ctrl> <Tab>
<Shift> <Tab>
<Tab>
<Shift> <Tab>
<Space>
<Up>
<Down>
<Pg Up>
<Pg Down>
<Home>
<End>
Focus next window and bring it to the front.
Focus the previous window and bring it to the front.
Select the following GUI element.
Select the previous GUI element.
Activate the focused button (highlighted with a dashed border)
Scroll up one line.
Scroll down one line.
Scroll up one page.
Scroll down one page.
Scroll to the beginning.
Scroll to the end.
Table 9.1: Keycodes for special editing functions.
9.4
Emergency Backup
In case HDevelop ever crashes during a program execution, an emergency backup is started which saves the recent program status to your hard disk from where you can retrieve it after restarting HDevelop to continue your application.
9.4 Emergency Backup 275
Figure 9.1: Example for an error window.
The exact location of the data depends on the operating system you are using. For Linux/UNIX you can retrieve your data from /tmp/hdevelop_login , and for Windows, the corresponding path is C:\
Documents and Settings\login \Local Settings\Temp\hdevelop. In both cases substitute login with your login name.
276 Tips & Tricks
Glossary 277
Appendix A
Glossary
Boolean is the type name for the truth values true and false as well as for the related boolean expressions.
Body A body is part of a conditional instruction (if) or a loop (while or for) and consists of a sequence of operator calls. If you consider the for-loop, for instance, all operator calls, that are located between for and endfor form the body.
Button A button is part of a graphical user interface. With the mouse the user can press a button to cause an action to be performed.
Control data Control data can be either numbers (↑integer and ↑real), character strings (↑string) and truth values (boolean). This data can be used as atomic values (i.e., single values) or as
↑tuples (i.e., arrays of values).
Empty region An empty ↑region contains no points at all, i.e., its area is zero.
Graphics window A graphics window is used in ↑HDevelop for displaying, e.g., ↑images, ↑regions, and ↑XLD.
HDevelop is an interactive program for the creation of HALCON applications.
Iconic data are image data, i.e., image arrays and data, which are described by coordinates and are derived from image arrays, e.g., ↑regions, ↑images and ↑XLD.
Image An image consists of one or more (multi-channel image) image arrays and a ↑region as the definition domain. All image arrays have the same dimension, but they can be of different pixel types. The size of the ↑region is smaller or equal than the size of the image arrays. The ↑region determines all image points that should be processed.
Iconic object Generic implementation of ↑iconic data in HALCON.
integer is the type name for integer numbers.
Operator data base The operator data base contains information about the HALCON operators. It is loaded at runtime from the binary files in %HALCONROOT%\help.
278 Glossary
Program window In HDevelop the program window contains the program. It is used to edit (copy, delete, and paste lines) and to run or debug the program.
Operator window In the operator window of HDevelop the parameters of the selected operators can be entered or modified.
Real is the type name for floating point numbers. They are implemented using the C-type double (8 bytes).
Region A region is a set of image points without gray values. A region can be imagined as a binary image (mask). Regions are implemented using runlength encoding. The region size is not limited to the image size (see also set_system(’clip_region’,’true’/’false’) in the HALCON reference manual).
String is the type name for character strings. A string starts and ends with a single quote; in between any character can be used except single quote. The empty string consists of two consecutive single quotes. The maximum length of a character string is limited to 1024 characters.
Tuple A tuple is an ordered multivalue set. In case of ↑control data a tuple can consist of a large number of items with different data types. The term tuple is also used in conjunction with ↑iconic objects, if it is to be emphasized that several ↑iconic objects will be used.
Type ↑iconic variables can be assigned with data items of type ↑image, ↑region, and ↑XLD. The types of ↑control data items can be one of ↑integer, ↑real, ↑boolean, or ↑string.
Variable window In HDevelop the variable window manages the ↑control and ↑iconic data.
XLD is the short term for eXtended Line Description. It is used as a superclass for contours, polygons, and lines.
Command Line Switches 279
Appendix B
Command Line Switches
HDevelop accepts the following command line switches: hdevelop (called as hdevelop) [options]
HDevelop options:
<program>.dev
- open the program for editing
-run <program>.dev
- load the program and start execution
<image_file>
-help
-version
--help
- load an image file with read_image
- show this help info in a message box
- show version information in a message box
- show this help information on the console
--version - show version information on the console
-convert <program>.dev <program>.{cpp,c,cs,vb,bas,cs,vb,txt,dev}
[-COM]
[-external_proc_path:<external procedure path>]
[-external_procs_only_interfaces]
[-reset_free_text]
[-no_use_hdevelop_template]
- convert an HDevelop program into a source file of the specified type
-reset_preferences - reset all persistent settings from previous sessions
-preferences <file> - start HDevelop with the preferences from a file
Qt options:
-style[=] <style> - sets the application GUI style. Possible values are: Windows Motif CDE Plastique Cleanlooks
X11 options:
-display <display> - sets the X display (default is $DISPLAY).
-geometry <geometry>- sets the client geometry of the first window that is shown.
-{fn|font} <font> - defines the application font. The font
280 Command Line Switches
should be specified using an X logical font description.
-{bg|background} <color>
- sets the default background color and an application palette (light and dark shades are calculated).
-{fg|foreground} <color>
- sets the default foreground color.
-{btn|button} <color>
- sets the default button color.
-name <name>
-title <title>
- sets the application name.
- sets the application title.
-visual TrueColor - forces the application to use a TrueColor visual on an 8-bit display.
-ncols <count> - limits the number of colors allocated in the color cube on an 8-bit display, if the application is using the
QApplication::ManyColor color specification. If count is 216 then a
6x6x6 color cube is used (i.e., 6 levels of
-cmap red, 6 of green, and 6 of blue); for other values, a cube approximately proportional to a 2x3x1 cube is used.
- causes the application to install a private color map on an 8-bit display.
Index 281
Index
* (asterisk) external procedure,
in window title,
.NET,
.avi,
.seq,
:Password,
#,
#$,
#$$,
#ˆ,
#ˆˆ,
$,
IC,
dev_set_check
,
PC,
Source image,
_COPY_1,
Live,
Detect,
Reset All,
Snap,
File,
Abort Procedure Execution,
About,
Acquisition menu (Image Acquisition Assistant),
Snap,
Acquisition menu
Live,
Acquisition Mode,
Activate,
Adapt program,
Add to User Tab,
Add Variable,
add_channels,
Advanced,
Advanced Autocompletion,
advanced autocompletion,
advanced model parameters,
advanced search parameters,
All,
Alternatives,
Always Find,
Angle Extent,
Angle Step,
Apply Immediately,
area_center,
assign,
assistant calibration,
Close Dialog,
Delete Generated Code Lines,
Exit Assistant,
image acquisition,
Insert Code,
Load Assistant Settings,
matching,
Release Generated Code Lines,
Save Current Assistant Settings,
Show Code Preview,
assistant settings, load,
assistant settings, save,
Assistants menu,
assure success,
Attention,
Auto
Disconnect,
Auto,
Auto Indent,
autocompletion,
AVI,
282 Index
Basics,
beginner,
Bit Depth,
boolean,
boolean operations,
break,
break point,
clear,
clear all,
set,
Browse Examples...,
Browse Examples...,
button,
C,
compile and link (UNIX),
compile and link (Windows),
export of HDevelop programs,
C++,
compile and link (UNIX),
compile and link (Windows),
export of HDevelop programs,
C#,
export of HDevelop programs,
Calibrate,
calibration,
Calibration Assistant,
calibration plate,
calibration plate extraction parameters,
calibration task,
Call Stack...,
camera parameters,
Camera Type,
Cascade Windows,
catch,
catch,
categories example programs,
Category,
channel gray value,
channel number,
channel selection gray histogram,
Chapters,
check box Always Find,
check box Pregenerate Shape Model,
check box Shape models may cross the image border,
Cleanup,
Clear All Breakpoints,
Clear Breakpoint,
Clear Graphics Window,
Clear Variable,
click,
clipboard,
Close Assistant,
Close Dialog,
Close Graphics Window,
Code Generation,
Image Acquisition Assistant,
Code generation,
code generation file,
image acquisition interface,
code generation, preview,
code lines, delete,
code lines, insert,
code lines, release,
code options,
Code Preview,
code variables,
Color,
color graphics window,
Color Space,
Colored,
Colors,
column,
Column Scale Step,
COM,
comment,
comment,
#,
#$,
#$$,
#ˆ,
#ˆˆ,
comparison operations,
Complexity,
concat_obj,
Connect,
Connection,
Image Acquisition Assistant,
connection,
Connection Handle,
continuation line,
continue,
Contrast,
Control,
control data,
Control Flow,
control flow break,
continue,
elseif,
exit,
for ... endfor,
if ...
else ...
endif,
if ...
endif,
operators,
repeat ... until,
return,
stop,
throw,
try ...
catch ...
endtry,
while ... endwhile,
coordinates status bar,
Copy,
variable values,
copy,
Copy History to Clipboard,
copy_obj,
count_obj,
Create Model,
create model,
Create New Procedure,
Create ROI,
Cut,
Deactivate,
Delete,
delete,
Delete All Test Images,
Delete All Unused Local,
Delete Current,
Delete Generated Code Lines,
Delete Test Image,
Delphi (Borland),
Detailed Description,
Detect,
Detect All,
determine pose bounds,
Determine Recognition Rate,
dev_ operators,
dev_clear_obj,
dev_clear_window,
dev_close_inspect_ctrl,
dev_close_window,
dev_display,
dev_display,
dev_error_var,
dev_error_var,
dev_get_exception_data,
dev_inspect_ctrl,
dev_map_par,
dev_map_prog,
dev_map_var,
dev_open_window,
dev_open_window,
dev_set_check,
dev_set_check,
dev_set_color,
dev_set_colored,
dev_set_draw,
dev_set_line_width,
dev_set_lut,
dev_set_paint,
dev_set_part,
dev_set_part,
dev_set_preferences,
dev_set_shape,
dev_set_window,
dev_set_window_extents,
dev_unmap_par,
dev_unmap_prog,
dev_unmap_var,
dev_update_pc,
dev_update_time,
dev_update_var,
dev_update_window,
Develop,
Device,
Dialog-based Editor,
Index 283
284 Index
dialog-based editor,
Directory,
Disabled,
Disconnect,
disp_circle,
disp_image,
disp_line,
disp_region,
Display,
Display Grid,
Display Image,
Display Image Pyramid,
Display Model,
display parameters,
Display Selected Test Image,
drag-and-drop,
Draw,
dump_window,
Duplicate...,
dyn_threshold,
Edit menu,
Edit program line,
Edit Interface,
Edit menu
Activate,
Copy,
Cut,
Deactivate,
Delete,
Find Again,
Find/Replace...,
Paste,
Preferences...,
Redo,
Undo,
Edit Procedure,
editor dialog-based,
full text,
Editor Mode,
else,
else,
elseif,
Emergency backup,
Enable the Context Menu in the
Graphics Window,
encoding,
native,
UTF-8,
endfor,
endfor,
endif,
endif,
endtry,
endtry,
endwhile,
endwhile,
error handling,
Error message,
escape strings,
Example,
example programs,
exception handling,
throw directly,
Exception handling,
Execute menu,
Execute menu
Abort Procedure Execution,
Call Stack...,
Clear All Breakpoints,
Clear Breakpoint,
Reset Procedure Execution,
Reset Program Execution,
Run,
Run to Insert Cursor,
Set Breakpoint,
Step Forward,
Step Into,
Step Out,
Step Over,
Stop,
exit,
Exit Assistant,
expert,
exponential functions,
Export,
UTF-8 encoding,
External Procedure Settings...,
external procedure, modified,
false,
Feature Histogram,
Feature Inspection,
Field,
File,
menu,
file history,
File menu
Browse Examples...,
Cleanup,
Export,
Insert All...,
Insert Mainbody...,
Insert Procedures...,
Insert Program,
New Program,
Open Program...,
Print,
Properties...,
Quit,
Read Image,
Recent Programs,
Save,
Save All,
Save Procedure As...,
Save Program As...,
file_exists,
Find Again,
Find Model,
Find/Replace...,
Font,
for,
for loop,
for,
frames per second
Image Acquisition Assistant,
Full Text Editor,
full text editor,
gauss_image,
gen_empty_obj,
gen_lowpass,
gen_tuple_const,
Index 285
General Documentation,
Generic,
get_error_text,
get_framegrabber_param,
get_image_pointer1,
get_mposition,
get_system,
Give Error,
graphics window,
graphics window,
clear,
close,
colors,
image size,
line width,
open,
regions,
select iconic variable,
window size,
Gray Histogram,
gray value histogram,
inspection,
status bar,
Greediness,
GUI,
guru,
H_MSG_FAIL,
H_MSG_FALSE,
H_MSG_TRUE,
H_MSG_VOID,
HALCON example programs,
modules,
HALCON News (WWW),
HALCON Reference,
HALCON XL,
HALCONIMAGES,
HALCONROOT,
HDevelop procedures,
external,
hierarchy,
local,
main,
286 Index
program export to C,
export to C++,
export to C#,
export to Visual Basic,
export to Visual Basic .NET,
HDevelop dev_ operators,
example programs,
language,
runtime error,
warning,
HDevelop Language,
HDevelop Reference,
HDevelop.ini,
Help,
About,
HALCON News (WWW),
HALCON Reference,
HDevelop Language,
HDevelop Reference,
Help,
menu,
Search Documentation,
history of files,
IC,
iconic data,
iconic object,
if,
if,
if,
ifelse,
ifelse,
image,
image acquisition assistant,
Image Acquisition Assistant,
Code Generation,
Connection,
frames per second,
Parameters,
Source,
Image Acquisition Interface,
image coordinates status bar,
Image File(s),
Image Files,
Image Object,
image properties status bar,
image pyramid, display,
Image Size,
image source,
Import,
Indent Size,
Insert
Code,
insert,
insert,
Insert All As Local,
Insert All...,
Insert Code,
insert cursor,
Insert Mainbody...,
Insert Procedures...,
Insert Program,
Insert Used As Local,
Inspect,
Interface,
Interface Library,
junctions_skeleton,
Keep dialog open,
keyboard,
keyboard menu access,
Keycodes,
Keywords...,
Language,
Last Pyramid Level,
LC_COLLATE,
Library,
line continuation,
Line Width,
Live,
Load Assistant Settings,
Load Model,
Load Test Images,
local procedure,
look-up table,
loop
body,
Loop Counter,
LUT,
Lut,
main window,
window title,
Make All External,
Manage Passwords,
Matching Assistant,
Max Column Scale,
Max Row Scale,
Maximum Number of Matches,
Maximum Overlap,
MDI,
MDI,
mean_image,
median_image,
menu
Acquisition (Image Acquisition Assistant),
Assistants,
Edit,
Execute,
File,
Help,
Operators,
Procedures,
Suggestions,
Visualization,
Window,
menu bar,
messages status bar,
Metric,
Min Column Scale,
Min Row Scale,
Minimum Component Size,
Minimum Contrast,
Minimum Score,
Miscellaneous,
model creation,
model image, display,
model image, open,
model parameters, advanced,
model parameters, standard,
model use parameters, advanced,
model use parameters, standard,
modified external procedure,
program,
mouse click,
Move Down,
Move Up,
multiple-document interface,
native encoding,
New Program,
New Zoom Window,
Normal,
number of visible objects,
Open,
Open Graphics Window,
Open Graphics Window...,
Open in new HDevelop,
Open Model Image,
Open Operator Window,
Open Program Listing,
Open Program...,
open test images,
Open Variable Window,
open_framegrabber,
open_window,
operating systems
UNIX,
Windows,
operation precedence,
operator data base,
window,
operator window,
operator window,
Operators
Control,
Develop,
menu,
submenus,
Optimization,
Optimization,
optimize parameters,
Optimize Recognition Speed,
Organize Windows,
Index 287
288 Index
orientation_region,
Output Destination,
Paint,
parameter expressions,
parameter Angle Extent,
parameter Angle Step,
parameter Column Scale Step,
parameter Contrast,
Parameter Documentation,
parameter Greediness,
parameter Last Pyramid Level,
parameter Max Column Scale,
parameter Max Row Scale,
parameter
Maximum Number of Matches,
parameter Maximum Overlap,
parameter Metric,
parameter Min Column Scale,
parameter Min Row Scale,
parameter Minimum Component Size,
parameter Minimum Contrast,
parameter Minimum Score,
parameter Optimization,
parameter optimization,
parameter Pyramid Levels,
parameter Row Scale Step,
parameter Start Angle,
parameter Subpixel,
Parameters,
Image Acquisition Assistant,
parameters, reset,
Paste,
paste,
PC,
pixel type,
pixel info,
Plot Quality,
Port,
pose bounds, determine,
Position Precision,
Predecessors,
preferences export,
HDevelop.ini (persistence),
import,
Preferences...,
Pregenerate Shape Model,
Print,
HDevelop procedure,
HDevelop program,
procedure,
program,
Procedure Name,
Procedures,
menu,
procedures documentation,
procedures (HDevelop),
export
C,
C++,
C#,
Visual Basic,
Visual Basic .NET,
external,
hierarchy,
local,
main,
Procedures menu
Create New Procedure,
Delete All Unused Local,
Delete Current,
Duplicate...,
Edit Interface,
Edit Procedure,
External Procedure Settings...,
Insert All As Local,
Insert Used As Local,
Make All External,
program counter,
program window,
edit line,
Properties...,
pull-down menu,
Pyramid Levels,
pyramid levels, lock model and model image,
pyramid levels, model,
pyramid levels, model image,
pyramid, display,
quality issues,
Quit,
Read Image,
read_image,
Recent Programs,
recognition rate, determine,
recognition speed, optimize,
Recursive,
Redo,
reduce_domain,
reference to assistant elements,
References,
Refresh,
regexp_match,
regexp_replace,
regexp_select,
regexp_test,
region,
colors,
empty,
line width,
shape,
regiongrowing,
regions visualization,
regular expressions,
Release Generated Code Lines,
Remove,
Remove from User Tab,
repeat,
repeat,
replace
Find/Replace...,
reserved words,
Reset,
reset graphics window,
Reset All,
Reset Parameters,
Reset Procedure Execution,
Reset Program Execution,
reset_obj_db,
Resolution,
Index 289
Restrictions,
return,
ROI creation,
row,
Row Scale Step,
Run,
Run to Insert Cursor,
Run Until Here,
runtime status bar,
Runtime error,
Save,
save local procedure,
Save All,
Save Current Assistant Settings,
Save Model,
Save Procedure As...,
Save Program As...,
Save Window ...,
scale range,
scale step size,
scale_image,
SDI,
SDI,
Search Documentation,
search object,
search parameters, advanced,
search parameters, standard,
See also,
Select Directory ...,
Select File(s) ...,
Select Graphics Window,
select test image,
Select...,
select_gray,
select_obj,
select_shape,
select_shape_xld,
semantics,
sequence file,
Set Breakpoint,
Set Parameters...,
set_check,
set_color,
290 Index
set_framegrabber_param,
set_line_width,
set_paint,
set_part,
set_system,
set_tposition,
set_system,
Shape,
shape model, load,
shape model, save,
Shape models may cross the image border,
Short Description,
shortcuts,
Show Caller,
Show Code Preview,
Show frames per second during live acquisition,
Show Procedure,
Show Processing Time,
sigma_image,
single-document interface,
skeleton,
smooth_image,
Snap,
Sort by Name,
Sort by Occurrence,
Source
Image Acquisition Assistant,
split,
standard model parameters,
standard search parameters,
Start Angle,
status bar,
Step,
Step Forward,
Step Into,
Step Out,
Step Over,
Stop,
stop,
stop
HDevelop program,
program,
strchr,
string,
concatenation,
operations,
special characters,
strlen,
strrchr,
strrstr,
strstr,
Subpixel,
Successors,
Suggestions,
Alternatives,
Keywords...,
Predecessors,
See also,
Successors,
suppress error messages,
syntax,
terminology,
test image sequence, delete,
test image, delete,
test image, display,
test image, select,
Test Images,
test images, load,
test model,
test_region_point,
threshold,
throw,
throw,
Trigger,
trigonometric functions,
true,
try,
try,
tuple,
concatenation,
tuple_abs,
tuple_acos,
tuple_add,
tuple_and,
tuple_asin,
tuple_atan,
tuple_atan2,
tuple_band,
tuple_bnot,
tuple_bor,
tuple_bxor,
tuple_ceil,
tuple_chr,
tuple_chrt,
tuple_concat,
tuple_cos,
tuple_cosh,
tuple_cumul,
tuple_deg,
tuple_deviation,
tuple_div,
tuple_environment,
tuple_equal,
tuple_exp,
tuple_fabs,
tuple_find,
tuple_floor,
tuple_fmod,
tuple_gen_const,
tuple_greater,
tuple_greater_equal,
tuple_int,
tuple_inverse,
tuple_is_number,
tuple_ldexp,
tuple_length,
tuple_less,
tuple_less_equal,
tuple_log,
tuple_log10,
tuple_lsh,
tuple_max,
tuple_max2,
tuple_mean,
tuple_median,
tuple_min,
tuple_min2,
tuple_mod,
tuple_mult,
tuple_neg,
tuple_not,
tuple_not_equal,
tuple_number,
tuple_or,
tuple_ord,
tuple_ords,
tuple_pow,
tuple_rad,
tuple_rand,
tuple_real,
tuple_regexp_match,
tuple_regexp_replace,
tuple_regexp_select,
tuple_regexp_test,
tuple_remove,
tuple_round,
tuple_rsh,
tuple_select,
tuple_select_range,
tuple_select_rank,
tuple_sgn,
tuple_sin,
tuple_sinh,
tuple_sort,
tuple_sort_index,
tuple_split,
tuple_sqrt,
tuple_str_bit_select,
tuple_strchr,
tuple_string,
tuple_strlen,
tuple_strrchr,
tuple_strrstr,
tuple_strstr,
tuple_sub,
tuple_sum,
tuple_tan,
tuple_tanh,
tuple_uniq,
tuple_xor,
Type,
type,
boolean,
integer,
real,
string,
Undo,
Unicode,
UNIX,
unnamed,
unsaved changes,
until,
until,
Index 291
292 Index
Update,
Update Graphics Window,
Update Image,
Update Program Counter,
Update Variables,
Update Window,
Use Model,
User,
UTF-8 encoding,
variable
_,
variable window,
variable window,
layout,
resize,
tabs (All, Auto, User),
variables,
view image pyramid,
view model image,
view test image,
Visibility,
visible objects,
Visual Basic,
export of HDevelop programs,
Visual Basic .NET,
export of HDevelop programs,
Visualization menu,
Visualization menu
Apply Immediately,
Clear Graphics Window,
Close Graphics Window,
Color,
Colored,
Display,
Draw,
Feature Histogram,
Feature Inspection,
Gray Histogram,
Image Size,
Line Width,
Lut,
New Zoom Window,
Open Graphics Window...,
Paint,
Position Precision,
Reset Parameters,
Save Window ...,
Set Parameters...,
Shape,
Update Window,
Window Size,
Zoom Window,
Volatile,
Warning,
warning,
watersheds,
while,
while loop,
while,
Window
Cascade Windows,
menu,
Open Graphics Window,
Open Operator Window,
Open Program Listing,
Open Variable Window,
Organize Windows,
Window Size,
window title,
Windows,
write_string,
X,
XLD,
colors,
line width,
Y,
Zoom,
Zoom Window,
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