OrthoMapper™ - Image Processing Software, Inc.

OrthoMapper
Softcopy Photogrammetric Software for the GIS,
Natural Resources and Engineering Professionals
From
Image Processing Software Inc.
Madison, Wisconsin 53705
www.orthomapper.com
OrthoMapper™
November 2005
OrthoMapper
Company Information:
Image Processing Software, Inc.
6409 Appalachian Way
Madison, WI 53705
USA
Phone:
Fax:
Web Site:
Image Processing Software, Inc.
PO Box 5016
Madison, WI 53705
USA
(608) 233-5033
(608) 238-7086
www.orthomapper.com
Copyright Notice:
This manual and the OrthoMapper software are copyrighted by Image Processing
Software, Inc. All rights are reserved. Neither the manual nor the software may be
reproduced without written permission from Image Processing Software, Inc.
OrthoMapper is a registered trademark of Image Processing Software, Inc., patents
pending.
Warranty: OrthoMapper is warranted for one year. There is a 30 day money-back return
policy, excluding the cost of shipping.
Software Support:
Unlimited support is given for the first 30 days.
Just call us, fax us , or send an email.
Email: mapsupport@orthomapper.com
After 30 days, support plans are available. Please contact us at the above address, phone
numbers or email.
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OrthoMapper
TABLE OF CONTENTS
Cover Page
Company Information
Table of Contents
Program Registration
1.0
Introduction
1.1
Requirements
1.2
Installation of OrthoMapper
Hardware Key
Software Key
1.3
Interacting with OrthoMapper
1.4
Workflow
1.5
Sample Data – Tutorial, see Appendix A
1.6
Preliminary Steps in the use of OrthoMapper
2.0
Main Menu – Starting OrthoMapper
2.1
Project
2.2
Open an Existing Project
2.3
Start a New Project
2.4
Selecting a Camera Sensor Model
2.5
Project Information Dialog Box
2.6
A Digital Camera is Indicated
2.7
Camera Using Film is Indicated
2.8
Project Directory
3.0
Orientation
3.1
Interior Orientation
3.2
Zoom In and Out
3.3
No Camera Calibration Report
3.4
With Camera Calibration Report
3.5
Automated Location of Fiducials
3.5.1
Additional Automation
3.6
Exterior Orientation
3.7
Visual Orientation
3.7.1
Change Z
3.7.2
Solve for Center
3.7.3
Measuring Tie Points
3.8
Manual Entry of Control Points
4.0
Producing Orthophotos
4.1
Automated Bundle Adjustment
Densify Points
Set Initial Weights
Adjust/Delete Tie Points
4.2
Select Image Parameters
4.3
Creating mosaics from large color images
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OrthoMapper™
5.0
5.1
5.2
5.3
5.4
5.5
6.0
6.1
6.2.1
6.2.2
6.3
6.4
6.4.1
6.4.2
6.4.3
6.5
6.5.1
6.5.2
6.5.3
6.5.4
6.5.5
6.5.6
6.5.7
6.6
6.6.1
6.6.2
6.6.3
6.6.4
6.7
6.7.1
6.7.2
6.7.3
6.7.4
6.7.5
6.8
6.9
6.10
6.10.1
November 2005
Image Display
Read
Display
Flicker/Split Window
SaveAs
Close
Enhance
Utilities
Change Display Parameters
Change/View Image Parameters
Test for Compatible Units
Change Coordinates
File Conversion
Create LAN/DEM from TIF/IMG & MrSid Files
Creating Orthophotos from Large Color Images
Converting 16-bit images to 8-bit images
Convert BIL/BSQ/RAW/DEM File
Convert BIL to DEM (National Elevation Data set)
Import /Mosaic/Create DEMs
Import DEM from Text File
From Regular Array of Points
From Irregular Array of Points
Create DEM from SDTS File
Create DEM from DXF File
Mosaic DEMs
DEM Arithmetic
Orthophoto Mosaic Functions
Update an Orthophoto
Manually Create an Orthophoto Mosaic
Automatically Create an Orthophoto Mosaic
Automatic Color Balance
One-Bit Overlays
MergeFill NoData
Change Color/Contrast of Image
Interactive Color Balance
Correct Lens Falloff/Uneven Illumination
Log and Exponential Transformation
Color Balance and Color Blend a Block of Images
Color Blend
Import Exterior Orientation Parameters
Rotate Image/DEM
Trim/Subset/Resize Images/DEMs
Trim Images or DEMs
Trim to polygon using visual subset
Trim to polygon file
Trim to rectangle
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6.10.2
Batch Trim
6.10.3
Trim Orthophotos before Mosaicing
6.10.4
Create Orthophoto Tiles
6.10.4.1 Create Tiles from Mosaic
6.10.4.2 Create Tiles from Individual Orthophotos
6.10.5
Resize Images/DEMs
6.11
Bundle Adjustment
6.12
Create Flicker Images
6.13
Stretch an Image to Map
6.14
Measure Point Function
6.15
Specialized Transformations
6.15.1
Extend DEM
6.15.2
Reorder Bands
6.15.3
Extract one Band
6.15.4
Create a Tilted Image
OrthoMapper Order Form
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Appendix A OrthoMapper Tutorial
Visual Orientation of an Image
Project Set-up
Interior Orientation
Zooming In and Out
Visual Orientation
Successful Orientation
Critical Steps to Mastery
Creating an Orthophoto
Choosing Tie Points
Creating a Bundle Adjustment
Updating an Orthophoto
Importing Exterior Orientation Parameters
Manually Creating an Orthophoto Mosaic
Creating an Orthorectified Overlay
Automatic Mosaicing and Color Balancing
Appendix B Preliminary Steps before using OrthoMapper
Downloading DEMs from USGS
Appendix C Transforming DRG Files along with an orthophoto
Determining the Affine Transformation
Appendix D Using a Multi-camera Array with OrthoMapper
Camera-to-camera Registration
Appendix E Using MrSid Files with OrthoMapper
Appendix F Format for Import of Exterior Orientation Parameters
Appendix G Application Notes
Orthorectifying Overlays
Correcting Soils Maps
Desert Scene Example
Color Image Example
A-1
A-2
A-2
A-11
A-13
A-14
A-17
A-18
A-27
A-29
A-33
A-41
A-52
A-74
A-92
A-106
B-1
B-2
C-1
C-2
D-1
D-2
E-1
F-1
G-1
G-1
G-19
G-24
G-26
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OrthoMapper™
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OrthoMapper
Thank you for purchasing OrthoMapper. Upon receipt of your program, please
complete this registration form, and return it to Image Processing Software, Inc. With
registration, you will receive notification of any updates for OrthoMapper.
Program Registration
Date_____________
Serial Number of OrthoMapper Key:
__________________
Name:________________________________________________
Address:
______________________________________________
______________________________________________
______________________________________________
______________________________________________
______________________________________________
______________________________________________
Phone:
___________________________________
Fax:
___________________________________
Email:
___________________________________
Website:
___________________________________
Your Applications for OrthoMapper: .________________________
___________________________________________________
. ____________________________________________________
. ____________________________________________________
. ____________________________________________________
. ____________________________________________________
Comments: .___________________________________________
___________________________________________________
___________________________________________________
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OrthoMapper™
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OrthoMapper
Software to Create Orthophotos
Designed for the GIS, Natural Resources, and Engineering Professional
1.0
INTRODUCTION
OrthoMapper is a program that can easily create orthophotos from scanned unrectified
photos. OrthoMapper features a unique method of entering the control necessary for
image orientation. This method is called visual orientation – a simple point-and-click
method of orienting images using existing DEM and either orthophotos or DRGs.
OrthoMapper is simply the easiest method of creating orthophotos available today.
1.1
REQUIREMENTS
OrthoMapper is designed to be used on an Intel based PC
Operating Systems:
Minimum Memory:
Recommended Memory:
CD-ROM Drive:
Hard Disk Space:
Parallel Port:
Swap Space:
Windows NT 4.0, Windows 98, Windows ME, Windows
2000, and Windows XP
64MB of RAM
128MB of RAM, Additional RAM will speed up operations
on large images.
Required for program installation.
A minimum of a 2 Gigabytes disk drive is required; a larger
disk may be required for large projects.
A parallel port to which you attach the hardware key is
required. The key is passive and will not affect the use of
the printer port. The hardware key is normally shipped
with OrthoMapper.
OrthoMapper requires swap space that is approximately
twice the size of the image(s) it is working on in addition to
the swap space required by the operating system. A 9" x 9"
black and white photo scanned at 25 micrometers requires
approximately 80 megabytes. A color image will need
three times the space of an equivalent black and white
image. If you allow the operating systems to manage swap
disk space, as is usually done in Window 95/98, then there
should be at least 250 megabytes of free space on the drive
your Windows folder is on, usually the C drive.
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OrthoMapper™
1.2
November 2005
INSTALLATION OF OrthoMapper™
OrthoMapper™ is supplied on a CD-ROM. The software must be installed on a
hard disk and will not operate without the hardware or software key supplied with
OrthoMapper. If you are using Windows NT, 2000 or XP, you must log on
as a user with Administrator privileges.
You cannot use OrthoMapper by just copying the program from the CD-ROM – it
must be installed using the setup program.
To install OrthoMapper:
Insert the OrthoMapper CD-ROM into your drive.
The Install Menu should automatically be displayed. Click on the Install OrthoMapper
button and follow directions.
If the Install Menu does not start automatically, do the following:
1. Click on the Start button at the lower left of your screen.
2. Choose the Run option.
3. Click on the Browse button.
4. Click on the setup.exe file in the root directory of CD-ROM.
5. Press the Run button.
Let the install program reboot your computer when the installation has finished.
You should be able to use OrthoMapper by double clicking on the icon on your
desktop.
Image Processing Software, Inc (IPS) licenses OrthoMapper for use on a single
computer. IPS supports two different methods of assuring that OrthoMapper will only
work on one computer. The user can choose a hardware key or a software key.
The hardware key is a microprocessor-based dongle that connects to the parallel port of
the computer. The hardware key can be moved to any computer with a parallel printer
port. OrthoMapper can then be used on the computer with the hardware key. The
hardware key gives the user the most flexibility for choice of the computer on which to
use OrthoMapper. The hardware key is normally shipped with OrthoMapper unless the
user has specifically requested a software key.
The software key is a method of selecting a secure certificate that allows OrthoMapper to
operate for 30 days for the Trial Version or for an unlimited time when OrthoMapper is
purchased. The software key is only operational on one computer. To “unlock” the
certificate, the user must send a file called “License_Info.Txt” to IPS to generate the key.
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Hardware Key
The hardware key supplied by IPS must be installed on the parallel port of the computer
on which the user wishes to use OrthoMapper. If the parallel port is connected to a
printer, connect the printer cable to the end of the hardware key after attaching it to the
computer. After installing OrthoMapper, you will not need to interact with the hardware
key.
Software Key
Please be advised that you cannot change your mind on which
computer OrthoMapper will be operational after you request a License
Key.
The version of OrthoMapper that is designed to work with the software key will not work
without a proper license key supplied by IPS. After installing OrthoMapper, start the
program by double clicking on the OrthoMap Icon on your desktop. You should click on
“Help” at the main menu, and then click on “License Entry”. The menu below should
then be displayed:
The Computer ID displayed at this menu is unique to the computer on which
OrthoMapper is run. When this menu is displayed, a file called “License_Info.txt” will
be created at the root directory of the C drive. The user should locate this file and email
the file to mapinfo@orthomapper.com. IPS will supply a User ID and a License Key
character string by return email. The user then must enter these data into edit boxes at
this menu and click on “Install License” button.
1.3
INTERACTING WITH OrthoMapper™
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In general, OrthoMapper™ is designed to be used like most Windows programs. The
mouse will be used extensively to choose options. The mouse and keyboard commands
will be detailed within the description of each of the functions and is summarized below.
Select an Option
Point Measurement
Image Zoom In
Image Zoom Out
Single Click with the Left Mouse Button
Single Click with Right Mouse Button or the S key. The S key
allows more precise pointing, as the mouse tends to move when
pressing a button.
Shift or Alt in conjunction with Left Mouse Button –OR – Mouse
wheel forward.
Shift or Alt in conjunction with Right Mouse Button –OR– Mouse
wheel backwards.
A very important limitation within OrthoMapper is it’s inability to
access files or folders that have embedded spaces. Be absolutely sure
that you choose folder names that do NOT contain spaces. Do NOT
create any files with spaces within the name.
1.4
WORKFLOW
A typical project to create a digital orthophoto product would consist of the following
steps:
1.
2.
3.
4.
5.
6.
7.
8.
Start a new Project
Enter file names for the orthophoto and DEM needed for the project.
Enter camera information.
Enter the name and location of the digital image to be used to produce the orthophoto.
Orient the digital image
Perform interior orientation on a photo
Perform a visual exterior orientation on a photo
Create an Orthophoto
The menu items within OrthoMapper™ are arranged so that the user will usually start on
the left side of the Main Menu and proceed to entries toward the right side of the
window. There are various import and export functions in the Utilities section which will
allow the user to exchange data with other software. If you are starting a new project, the
large icons below the main menu provide all the functions that need to be used.
OrthoMapper™ uses a custom format ( .LAN ) for the digital images within a project.
OrthoMapper™ recognizes two additional formats, .TIF images and images created by
Erdas Imagine ( .IMG format). Many other image formats can be converted to .LAN
files using the Utilities Menu.
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1. When creating a new project, be sure to copy the file(s) you wish to use to a location
on a hard disk.
2. You should enter the names of the files you will be using as they are on the hard disk
into the project. OrthoMapper will automatically convert a .TIF or .IMG to a .LAN
during the Interior Orientation process. Files with other formats must be first
converted to .LAN files using the OrthoMapper utilities before you create the
project.
3. Orthophotos are created as GeoTIF files. A TIF World file (.TFW) is also created, so,
most any GIS program such as ArcView™ or ArcGIS™ can read the orthophoto files
and associated coordinates.
1.5
SAMPLE DATA --- TUTORIAL
On the CD-ROM is a directory called OM_TUTORIAL. This directory on the CD-ROM
should be copied to the root directory of any hard disk on your system. See Appendix A
for a description of the project and a tutorial on the use of OrthoMapper. It is highly
recommended that new users work through this tutorial before attempting to use
OrthoMapper.
1.6
PRELIMINARY STEPS IN THE USE OF OrthoMapper
To use OrthoMapper, an existing DEM is required. In addition, an existing
orthophoto/DRG can be used for the X,Y coordinates during orientation. Alternately, a
number of known ground coordinates, identified on the aerial image, can be used to
orient the image. The most important aspect of using existing DEM’s and reference
orthophotos is to assure that the coordinate system (and projection) is the same for the
DEM and the reference orthophoto (or ground coordinates). This will be the coordinate
system used to produce the orthophoto within OrthoMapper.
The important preliminary steps are:
1. Scanning the Image
2. Importing a DEM
3. Importing an existing orthophoto and/or DRG for X,Y control.
These important steps are discussed in Appendix B. A good understanding of these
import issues is important before you start to use OrthoMapper on your own projects.
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2.0
MAIN MENU
November 2005
STARTING ORTHOMAPPER
When the program is executed, the following menu is displayed:
The main menu of OrthoMapper™
OrthoMapper™ is designed to be used starting on the left of the main menu (Project) and
progressing toward the right performing the first three functions: Project, Orientation,
and OrthoPhoto. The Image Display menu option allows the display of images. The
Utilities Menu can be used to import a DEM from other programs or downloaded files
from the Web. Each of the Menu items at the Main Menu is explained below:
2.1
PROJECT
Each session of work with OrthoMapper usually begins by selecting an option from the
Project entry on the menu or pressing the START button. These allow the user to either
create a new project or open an existing project. If a new project is selected, dialog
boxes are displayed to allow the user to specify the images in the project and the camera
information.
When the Project Menu item is clicked on, the following pull down dialog box is
displayed:
2.2
OPEN AN EXISTING PROJECT
This option will allow the user to open an existing project. After choosing this option, a
dialog box will be displayed on the screen to allow the user to choose a project file. All
project files have an extension of .PJ If a project file is successfully opened, a message
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to this effect is displayed on the screen. Once a project has been opened, other functions
can be chosen.
2.3
START A NEW PROJECT
This option allows a user to create a new project. This is the first option to be used when
using OrthoMapper. When this option is chosen, or the large START button is pushed,
Project Creation Wizards are started. The user is asked a number of questions about the
new project.
The first screen in the Creation Wizards is a welcome message and a reminder that before
you embark on creating orthophotos, you should be sure that you have all of the correct
material on hand. You must be sure that the data you will be using as control has
coordinates in the same datum and projection. If you have not already made sure your
control data is all in the same system, now is the time.
You have two choices before you go on to create a project for OrthoMapper. You can:
1.
2.
Indicate that you will be using Visual Orientation within the project.
Indicate that you only be using traditional ground survey points for control.
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If you have existing orthophotos or DRGs covering the extent of the imagery you wish to
make into orthophotos, the first option – Visual Orientation – is the easiest way to make
your orthophoto.
Only choose the second option if you do not at all want to use Visual Orientation. Even
if you want to do a combination of Visual Orientation and survey ground coordinates,
choose the first option.
The third option is designed for projects with many images from the same photo mission
for which an orthophoto mosaic will be produced. You must have an existing Area
Directory and Single Photo Project already oriented to choose this option.
After choosing the second option, “Only ground coordinates … “, you will go directly to
pick the Camera Model for the project. You can skip forward to section 2.4, Selecting a
Camera Sensor Model.
If you choose the first option, “Visual Orientation … “, you will be asked to enter the
orthophotos/DRGs and the DEMs you will be using in the project.
The following dialog box is displayed:
You can add up to four orthophotos or DRGs to your project from this dialog box. For
each orthophoto or DRG you wish to add, click on the “Add an Ortho” button. When
you are finished adding orthophotos and/or DRGs, press the “Finished” button.
When you “Add an Ortho” the program will allow you to Browse to choose the
orthophoto/DRG. In addition, you can change the units of the orthophoto at the dialog
box, but only do this if you are absolutely sure that you know the file is incorrect.
The Add an Orthophoto/DRG dialog box is displayed on the next page.
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When you are finished adding orthophotos/DRGs, you then must indicate the file names
for the DEMs you will be using.
Again like the orthophotos, you can add up to 4 DEMs for a project.
If you are using DEMs acquired from the USGS it is highly
recommended that you mosaic the DEMs together (see the Utilities
Menu) before using them in a project. The mosaic process will fill in
gaps between the individual DEMs.
The “Add a DEM” button is similar to the “Add an Ortho” button. A click on the
button brings up the Add a DEM file dialog box.
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November 2005
In addition to allowing you indicate the file names for a DEM to add to the project, this
dialog box also allows you to specify that a Flat DEM is to be used instead of a real
DEM. If the area you are working on is very flat ( a wetland, or the state of Florida, for
example), you can use this option. If you choose this option, you must enter an elevation
in meters to specify the flat DEM.
When you are finished entering DEMs, press the “Finished” button to choose the camera
model for the project.
2.4
SELECTING A CAMERA SENSOR MODEL
The next dialog box allows you to choose the camera model for the project. The vast
majority of projects will use a single frame camera – the first option on the dialog box.
If you choose the second option, “Multiple Frame Cameras”, you will be asked to choose
a band with which to orient the image. In this case, OrthoMapper will display a single
band during all of the orientation processes. This is to avoid the problems with
registration of the image between the cameras. The Camera-to-camera registration is
accomplished at the point an orthophoto is produced. See Appendix D for more
information.
If you are rectifying an Ikonos Satellite Image, see Appendix E for further instructions.
2.5
PROJECT INFORMATION DIALOG BOX
After pressing the “OK” button on this dialog box, the Project Information dialog box
appears. This dialog box is shown at the top of the next page.
The user is expected to use the Browse button to choose the Area Directory for the
project. The Area Directory is the directory on the file system in which all the projects
(or images) that you expect to be combined together into an orthophoto will be located.
Each project will contain information on one image.
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Project Information Dialog Box
If the Area Directory does not exist, you will be given a chance to create the directory.
After clicking on the first Browse button, you will see the two dialog boxes depicted
below.
Use BROWSE to find files and use normal WINDOWS procedures during the following
discussion
Select Area Directory Dialog Box
Browse for Folder Dialog Box
The dialog box on the left will first be displayed. The Select Directory button should be
pushed. The dialog box at the right will then be displayed. You should choose the drive
on which you want the Area Directory, then expand the tree display by clicking on the +
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next to the drive icon. If the Area Directory exists, click on the directory. If the
directory does not exist, click on the directory in which you wish to create the Area
Directory. You may wish to just click on the disk drive icon. In this latter case, the Area
Directory will be a directory directly beneath the root directory of the chosen drive.
The figure on the right depicts an example of a user
choosing an existing Area Directory called
VisArea1, which already has three projects within
the area.
If the Area Directory does not exist, after choosing
the base directory, enter the name for the Area
Directory in the edit box within the Select Area
Directory dialog box (see figure above). After
entering the new directory name, press the Create
Directory button to the right of the edit box.
After pressing this button, the full path name for the Area Directory should appear at the
top of the Select Area Directory dialog box. Press the Finished button at the bottom of
the dialog box to return to the Project Information Dialog Box.
Once you return to the Project Information Dialog
Box, you must next enter the information regarding the
images to be rectified. Press the Browse button to the
right of the Image File Names edit box. You should
select all of the images you wish to be included in an
orthophoto mosaic at this time. All the images must
have the same camera calibration information.
After choosing the image file, press the Next button at
the bottom of the Dialog Box.
The next question the user is asked is to
indicate if the image was taken with a
digital camera. Only click on the “Yes”
radio button if the image in this project
was taken with a digital camera. In most
cases, the digital image used was taken
with a conventional camera and film. The
film was then turned into a digital image
using a scanner.
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2.6
November 2005
A DIGITAL CAMERA IS INDICATED
If a digital camera is indicated, then the user is asked a number of questions relating to
the camera.
Enter Camera Name. This dialog box
allows you to identify the camera used for
this project. This name will be stored in the
camera file, but is not used during the
production of the orthophoto.
Enter the focal length of the lens. Normally
these will be relatively small numbers, 12 to
40 mm.
You should check with the camera
manufacturer to determine this number. It is
critical that you have the correct number for
the focal length of the lens
Size of Pixel -- This is the spacing between
detectors in the focal plane of the camera.
Again this can be obtained from the
manufacturer of the digital camera.
Note that the units of the pixel size can be
microns, millimeters or DPI (dots per inch).
The maximum size for a pixel is 0.125 mm
(125 microns).
If the image being processing is an
enlargement, you must check the box at the
bottom of the menu. You must also enter
the enlargement size if this box is checked.
Press the Finished key, and you will be
finished with creating the project. The
project directory will be created in a subdirectory of the Area Directory. The Project
Directory will be the same name as the
image name. Within the Project Directory,
the actual Project File Name will also be the
image name with an extension of .PJ .
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2.7
November 2005
CAMERA USING FILM IS INDICATED
If you answered No to the digital camera
question, you will be asked a number of
questions about the camera.
Do you have a camera calibration for the
camera?
The firm who took the photographs usually
supplies the camera calibration information.
It is usually supplied in the form of a report
for the USGS.
If you indicated that you do NOT have a
camera calibration report, you will be asked
to enter the Number of Fiducials. You have
a choice of entering the number 3 or 4
within this dialog box. Enter 3 if a standard
81/2 x 11 desktop scanner was used to
produce the digital imagery. Enter 4 if a
larger format scanner was used to produce
the digital imagery.
You will next be asked to enter the focal
length of the lens and the size of the pixel
(see previous section).
If you indicated that you have a camera
calibration report, you will be asked to enter
information from the camera calibration
report.
You will next be asked to enter a Camera
Name. The program does not use this
information directly but it can be used to
verify that the correct camera calibration
report was used to enter the information.
Press the Next button to answer the next
question.
You must next enter the Calibrated Focal
Length of the lens from the calibration
report.
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OrthoMapper™
November 2005
For a normal mapping camera, the focal
length should be approximately 152 mm.
You should look at the camera calibration report for this number. You should enter this
number with three significant decimal places (for example: 152.815).
Next you will be asked for the Calibrated
Principal Point. This is the calibrated center
of the lens. These are usually very small
numbers, less than 10 microns ( 0.01 mm).
They can be positive or negative and are
entered as mm.
The Radial Lens Distortion Parameters are
entered next. These are very small numbers.
The numbers should be entered using an
exponential notation. For example, the
number 0.000045431 would be entered as
4.5431E-5. The -5 indicates that the
decimal place is to be moved to the left by 5
places. You must enter a number for each of
Parameters, even if it is 0. If your camera
calibration report only contains distortions
verses angle or radius, click on the Calc
Params button. This button will bring you
to a menu that will calculate the K
parameters. After you press the Next button
at this menu, the Number of Fiducials Menu
will be displayed (shown on page 17).
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OrthoMapper™
November 2005
Calc Params Menu
The following menu will be displayed when the Calc Params button is clicked.
You must click on one of the two radio buttons toward the top of the menu. If you have
data that gives you the radial distortions as a function of radius, click the top button. If
you have data that gives you the radial distortions as a function of angle, click the second
button. Camera files produced in the United States usually contain the angle information.
The reports produced in Europe, usually contain the distortions as a function of radius. If
you click on the Print information in Log File check box, a log file will be created in the
root directory of the C drive with the information entered.
After clicking on one of the radio buttons, the following menu will be displayed.
If the Focal Length is not displayed, enter it in the edit box.
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OrthoMapper™
November 2005
You are expected to enter the Angle (or Radius) and Distortions values. After entering
each pair of values, the Enter Data button must be clicked. The values will be entered in
the combo list at the bottom of the menu. Each pair of values must be entered in a
similar fashion. When you are finished entering values, review the entries and then press
the OK button. Below is an example of the menu displayed after entering a number of
pairs of values.
After pressing the OK button, you will be returned to the Radial Distortion Parameters
Menu with the K’s entered in the menu.
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OrthoMapper™
November 2005
Number of Fiducial Points Menu
The number of Fiducial Marks or Points
must be entered next. The list of Fiducial
Point coordinates can usually be found on
the third page of the USGS Camera
Calibration report. After you have entered
the number of Fiducials, press the Next
button.
Coordinates of Fiducal Points Menu
For each of the Fiducial points, you must
enter the X and Y coordinate. These are
found in a table in the calibration report. Be
sure you type these in carefully and note the
positions of each of the Fiducial Marks. On
the following page in the calibration report
with the fiducial coordinates is a diagram
that gives the locations of the fiducials.
Make a note of this diagram, as you must
measure the corresponding points on the
image during the Orientation process. Note
that the Fiducial numbering is relative to the
data strip side, not necessarily the top of
the image or where the side of the image is
labeled. Refer to your camera calibration
report for the locations of the fiducials for
camera calibrations measured outside the
United States.
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OrthoMapper™
November 2005
The data strip side can be located by finding where the clock is imaged or other camera
specific information is imaged. On the next page is an example of an image with the data
strip on the right of the image and titling at the left of the image. The fiducials are
numbered in red. These are the typical locations for eight fiducial marks.
Fiducial 4
Fiducial 1
Fiducial 8
Fiducial 6
*
Fiducial 5
Image Title
Data Strip
Fiducial 2
Fiducial 7
Fiducial 3
Example image with the Data Strip and Fiducials indicated.
After entering all of the fiducial information, press the Finished button and the project
will be created.
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OrthoMapper™
2.8
November 2005
PROJECT DIRECTORY
The project directory will be created in a sub-directory of the Area Directory. The
Project Directory will be the same name as the image name, so you can keep track of it.
Within the Project Directory, the actual Project Name, will be the image name with an
extension of .PJ . For example, if the Area Directory is located on the F drive and is
called Area1, and the image used in the project is called 194.LAN, the following will be
created:
Area Directory:
Project Director:
Project File:
F:\Area1\
F:\Area1\194\
F:\Area1\194\194.PJ
All of the project directories for the images chosen in the Image File Names edit box (on
page 11) will be created at the same time. You will not be asked for any additional
information (such as camera calibration, etc.).
Note: It makes no difference in which directory the image used in the project resides.
Only the image name is used to make up the project directory name and project file
name.
20
OrthoMapper™
3.0
November 2005
ORIENTATION
There are two types of orientations necessary within OrthoMapper™. Interior
Orientation refers to determining the relationship between the rows and columns on
your digital image and the physical measurements on the original image. Exterior
Orientation refers to determining the geographic position and attitude of the image when
the picture was taken. If you click on the large ORIENT button on the main menu, the
program will guide you through each of the procedures.
3.1
INTERIOR ORIENTATION
The intent of the interior orientation procedure is to determine the relationship between
the rows and columns on your digital image and measurements on the original image. If
you have indicated that you have a camera calibration, you will be measuring the
positions of each of the fiducials on the digital image. If you indicated that you do not
have a camera calibration, you will be measuring the positions of four points (four corner
or four side fiducials) that will be used to determine the center of the image and the
image coordinate system. In both cases (with and without a camera calibration) the
operation is essentially the same.
If you indicated that you have a camera calibration report, you must measure the fiducial
points indicated in the report. The fiducials are marked with crosshairs or circles on the
image (see example image in the last section). The approximate locations of the fiducial
marks are indicated in a diagram in the report. The coordinates specifying the precise
positions of the fiducials are also given in the report. In order to assign the right
coordinates to each fiducial, it is necessary to locate the side of the image, which has the
data strip. This is information that the camera records along one side of the film negative
as the picture is taken. The data strip side is marked on the diagram. On the image the
data strip side can be located by finding where the camera recorded its clock image or
other camera specific information. The data strip side is not necessarily the same as the
side where the title and date are (see example image in the last section).
If you are not using a camera calibration report, you can measure the four Fiducial Points
to determine the center of the image in any order.
When you start the interior orientation, two images, a dialog box, and a help box are
displayed.
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OrthoMapper™
November 2005
Full Resolution Subset
Index Image
The user is presented with a dialog box in which is displayed each of the fiducials along
with row and column coordinates measured by the user. To measure a fiducial, the user
first clicks on the radial button at the beginning of the line containing the information for
that fiducial. Then the user must click with the Right Mouse Button on the position of
the fiducial in the index image, which shows the digital image at 1/10 resolution. A full
resolution sub-image of the area clicked on will appear in a separate window. (If the
fiducial does not appear in the sub-image, one may right click again on the index image
at different locations until the fiducial appears.) Finally the user moves the cursor to the
center of the fiducial and clicks with the Right Mouse Button or presses the S key. The
position of the cursor is then automatically recorded in the dialog box, completing the
measurement of the selected fiducial.
If the user makes a measurement on the full resolution
image (with the Right Mouse Button or the S key) for a
point already measured, the data will not be overwritten
unless the point number is confirmed. If you wish to store
the measurement at the point indicated Select Point dialog
box, press the OK Button. If you wish the measurement to
be stored at a different point location, click on the
appropriate button to the left of the Point number.
3.2 ZOOM IN AND OUT
The fiducial row and column coordinates are not necessarily whole numbers because the
crosshairs of a fiducial allow one to find the center position of the fiducial to within a
fraction of a pixel. To get the best estimate of the center one should zoom in on the
fiducial until it fills most of the sub-image window. To zoom in, hold down the Alt key,
position the cursor at the center of the area you wish to magnify, and press the Left
Mouse Button or roll the mouse wheel forward. To zoom out, press the Right Mouse
Button along with the Alt key or roll the mouse wheel backwards. Using the Shift key
instead of the Alt key will zoom in and out in bigger increments.
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OrthoMapper™
November 2005
The same techniques can be used to zoom in on the index image if you are having
problems locating a fiducial on it.
3.3
NO CAMERA CALIBRATION REPORT
If you indicated that you did not have a camera calibration report, you are expected to
measure 3 or 4 fiducials. You can choose either the four side fiducials or the four corner
fiducials. Some of the older cameras only have four fiducials, so you may not have a
choice.
The procedure will be:
1. Position the cursor on the index image on one of the fiducials, click with the Right
Mouse Button.
2. Zoom in on the Full Resolution image using the Alt and Left Mouse Button so that
the fiducial is centered with the red crosshairs.
3. Press the S key to make a measurement.
4. Repeat the above three steps for the other two or three fiducials you have chosen.
When you have measured all three or four of the fiducial points and the Green Icon
appears, press the Finished Button to go on to the Exterior Orientation.
3.4
WITH CAMERA CALIBRATION REPORT
If you indicated that you have a camera calibration report for your image, you are
expected to measure all of the fiducials indicated in the report. OrthoMapper will
accept a minimum of four measurements (out of eight), but this will adversely impact the
quality of any orthophoto produced. The procedures to complete the interior orientation
are as follows:
1. Click on the first Radio Buttons in the dialog box (Point 1, for example).
2. Position the cursor on the index image on the corresponding position of that fiducial,
click with the Right Mouse Button. Be sure that you are choosing the correct
position!
3. Zoom in on the Full Resolution image using the Alt and Left Mouse Button so that
the fiducial is centered with the red crosshairs. Press the S key to make a
measurement.
4. Repeat the above three steps for all of the other fiducials detailed in the calibration
report.
Press the proper Radio Button when the Point Selection dialog box pops up.
Be sure that you change the selection of the Radio Button for a measurement on a new
fiducial.
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OrthoMapper™
3.5
November 2005
AUTOMATED LOCATION OF FIDUCIALS
If a camera calibration has been indicated, OrthoMapper can locate all the remaining
fiducials after four are measured. As soon as four of the fiducials are measured, a least
squares fit is calculated for the measured points and the residuals are displayed in the
dialog box. Any of the fiducials can be remeasured if the residuals are larger than
expected. After 4 fiducials are measured, the program will display the full resolution
subset without pointing to the reduced resolution copy. Just click on the button to the left
of the appropriate Point number on the menu.
The interior orientation can be considered successful when the residuals are less than ½
the size of one pixel in both rows and columns. The RMS Difference displayed in the
dialog box is in units of pixels.
When you have measured all of the fiducials, press the Finished Button to go on to the
Exterior Orientation.
3.5.1
Additional Automation
The first time the fiducial points are measured for a camera, OrthoMapper records the
appearance of all of the fiducial marks. For any other images that use this camera file,
the user is only required to measure the first two fiducial marks and OrthoMapper will
measure the remaining points. The automated procedure will only work if fiducial 1 and
fiducial 2 are measured.
In order for this feature to work properly, all images must be scanned
with the data strip oriented the same way. For Example, the data
strip always on the left side of the digital imagery.
If, for some reason, one wishes to disable the automated measurement feature, the
“Disable AutoFind” box can be checked. If the user wished to store the locations of the
fiducials after the first time an image is measured for a given camera file, “Reset AutoFiducials” then click the “Finished” button.
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OrthoMapper™
3.6
November 2005
EXTERIOR ORIENTATION
When you have finished with the interior orientation, OrthoMapper will automatically
start the exterior orientation procedure. Before starting this procedure, you must have a
DEM and an orthophoto (or DRG) of the area over which your digital image was
acquired. The two files must be available on your computer. The DEM must be a file
with an extension of .DEM and the orthophoto (DRG) must be a file with an extension of
.TIF or .LAN. See the section 1.7, Preliminary Steps in the use of OrthoMapper, at
the beginning of this manual.
The exterior orientation within OrthoMapper is a relatively simple task. The
orientation uses a Visual Orientation Procedure. This means that all you need to do is
find corresponding points on an existing orthophoto as well as the image you wish to
orient. If a DRG is used in place of the existing orthophoto, you will be limited to using
features common between the new photo and the DRG. The program also allows you to
manually enter known control points directly. These might be points you have measured
using a GPS unit or have measured on a USGS topographic map.
When the Visual Orientation Procedure is called, the following dialog box is displayed:
Most of the entries are self-explanatory. The name of the image to orient should be
displayed in the first edit box.
The next edit box is very important. You must enter the direction for the top of the digital
image you are orienting. OrthoMapper uses this information to construct a North at top
index image so you can easily recognize common features between your digital image and
the reference orthophoto (which has North at the top).
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OrthoMapper™
November 2005
If you are going to create an orthophoto mosaic and wish to use the automated bundle
adjustment built in OrthoMapper, you must also set the “Flight Line Direction” box.
This will be used to give you guidance on where to select Tie Points. These Tie Points
will be matched on any overlapping images to allow a high quality bundle adjustment.
The names listed in both the DEM and Orthophoto list boxes should not need to be
changed. If you wish, you can add additional DEMs or orthophotos.
Press the OK Button to proceed with the Visual Orientation. The Visual Orientation
procedure is described in the section entitled Visual Orientation.
Note, additional reference orthophotos/GIS files can be added later at the Visual
Orientation Menu.
If you wish to manually enter known points on the image for the orientation, check the
box entitled “Manually Enter Control Points”. After checking that box and pressing the
OK button, you will be able to manually enter control points. The procedure is described
in section 3.8 which is entitled “Manual Entry of Control Points”.
3.7
VISUAL ORIENTATION
When the OK Button is pressed within the visual orientation dialog box, OrthoMapper
will display two index images, two full resolution images and a dialog box. The index
images are 1/10 resolution images of the reference orthophoto and the image to be
oriented. The dialog box displays the orientation thus far. In the example displayed on
the next page, 7 points have already been chosen.
To interact with this orientation procedure, click on corresponding points on the index
images using the Right Mouse Button. When the Full Resolution images are displayed
toward the bottom of the screen, click on the corresponding points using the Right
Mouse Button (or the S key). When you are satisfied with both locations, click on
Measure Point Button within the dialog box on the right side of the screen. It is
recommended that you choose at least 6 corresponding points to arrive at a reasonable
orientation. The Sigma variable displays the standard deviation of the least squares fit.
Numbers less than 3.0 are usually acceptable for scanned paper prints. A number less
than 1.0 is expected for transparencies scanned with a high quality scanner.
26
OrthoMapper™
Orthophoto Index Image.
November 2005
Digital Index Image
Full Resolution Orthophoto Full Resolution Image
A Left Mouse Button click near a control point on any image will set the point number
in the dialog box. One can delete a point and up to 20 points can be restored after delete
using the UnDo button.
The orientation of the red crosshairs in the high-resolution image can be changed
to more easily be lined up with a road or linear feature. To change the orientation,
choose a point in the high-resolution image and while holding down the Ctrl key,
press the Left Mouse Button. Move to another spot on the linear feature and
repeat this. One of the lines of the red crosshairs should be lined up along the line
you specified. To change the crosshairs back to a vertical and horizontal
orientation, enter Ctrl/Right Mouse Button.
3.7.1
Change Z
If you are sure that the point you have chosen is at a different elevation than that of the
DEM, you can enter the corrected Z in the Z edit box -- then click on the button
“Change Z”. This option should be used with caution since the entry of an incorrect Z
will cause the orientation to be wrong!
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OrthoMapper™
3.7.2
November 2005
Solve for Center
If the image that is to be orthorectified is not a complete aerial image, one should click
on the “Solve for Center of the Image” check box. If this option is used, a large
number of points should be taken to orient the image. Below is an example of this box
checked and an example image that is to be orthorectified is displayed on the left.
This option might be used to rectify published
soils maps. The above image was published at a
scale of 1:15,840. The original aerial image was
taken at a scale of 1:40,000. Thus the image is a
2.525 enlargement. The print was scanned at
400 DPI. Both these values should be entered
when the project is created – at the “Size of Pixel
Question” shown on page 12.
Optionally, the weights used in the solution can
be changed after choosing the “Solve for Center”
option by pressing the “Set Weights” button (see
below).
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OrthoMapper™
3.7.3
November 2005
Measuring Tie Points
If the image will be part of a mosaic and there is at least 60% overlap between the
images within a strip, you will want to also collect TIE points on the image displayed.
Tie points will be used during the orientation procedure to tie the individual images
together and assure that there is a consistent coordinate system for the orthomosaic. A
Tie point can be any well-defined point on the aerial image and is NOT measured on
the adjacent orthophoto (on the left).
To enter Tie points, press the “Measure
Tie Points” button.
The entry menu changes and a set of green
and magenta guidelines appear on the
index image.
The guidelines are an indication of the
area where the Tie points should be
measured. Tie points must be measured
in a line perpendicular to the direction
of aircraft flight as well as parallel to
adjacent strips. Points should be
measured in the magenta rectangles only if
there are adjacent strips of imagery. In the
above image, the aircraft was flying from
left to right. The coordinates for Tie
points are not needed; -- they just must be
sharp, well-defined points. Even a field
boundary can be an acceptable tie point as
pictured below.
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OrthoMapper™
November 2005
Just clicking with the Left Mouse button
or entering the “S” key, when the cursor is
on the high-resolution image, will measure
the Tie point – no need to press the
“Measure Button”.
OrthoMapper will attempt to
automatically find these points on all other
images on which they appear within your
mosaic project. These points are only
measured on the high resolution image
displayed after left clicking on the right
index image.
Example of a Tie point at a field boundary.
After you are satisfied you have chosen enough control and tie points, press the
Finished Button. You can now make your orthophoto unless you need to orient
additional images to be used within a mosaic. Each image must be oriented in a
separate project.
3.8
MANUAL ENTRY OF CONTROL POINTS
If your control points have been acquired via a ground survey or with GPS readings, they
should be entered at this menu. The user should be aware that the elevations acquired
using a GPS unit must be corrected for the local geoid. In addition, the X, Y coordinates
entered at this menu must be in the same projection and datum as the DEM that will be
used to make the orthophoto. Either the X,Y points entered in this menu must first be
translated using the Change Coordinates Option in the Utilities Menu, or the DEM must
be translated to projection/Datum of these points.
It is suggested that the user import all control points from a text file into this menu. Once
the control points have been imported, the X,Y,Z coordinates are automatically entered
when a point ID is chosen from the drop down menu. Also, after two points have been
chosen, the program can automatically drive to the location of the control point on the
image if the points have been imported.
When the Manual Entry of Control Points is called, the dialog box and images displayed
are shown on the next page:
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OrthoMapper™
November 2005
The upper image is a 1/10 resolution index
image of the image being oriented.
The image to the left is a full resolution
around the yellow square in the upper
image.
To enter a control point:
1. Click with right button on the index image at the approximate position of the control
point.
2. Locate the exact position of the control point on the lower image and press the S key or
Right Mouse Button.
9. Enter a point ID in the Ground Point ID drop down menu.
10. The X,Y, Z values should be automatically transferred if the point is stored in the
drop down menu. If the point is not in the drop down menu, you will need to enter a
value for X, Y and Z in the appropriate boxes.
11. Be sure that the units are correct for all the values.
12. Press the “Measure Button”.
As with all of the image displays within OrthoMapper, to zoom in hold down the Alt
key and press the Left Mouse Button; To zoom out, hold down the Alt Key and press
the Right Mouse Button.
Other options within this menu:
1.
Delete Point – Choose an existing point from the drop down menu, and then press
the Delete button.
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OrthoMapper™
2.
3.
4.
November 2005
Go to Point -- Choose an existing point from the drop down menu, and then press
the Go to Point button.
Go to Ground Point -- After two points have been entered you can choose a point
in the drop down menu and the program will navigate to the approximate point in
the image, awaiting only for you to correctly position the cross on the high
resolution image and press the Measure button.
Import/Edit -- This option allows you to import control from a text file and/or edit
existing control points already entered.
If the Import/Edit button is chosen, the following dialog box will be displayed:
To edit a point:
1.
2.
3.
Choose the point in the drop down menu.
Enter the new values in the appropriate edit boxes.
Press the “Edit Point” button.
To Delete a point:
1.
Choose the point in the drop down menu.
2.
Press the Delete button.
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OrthoMapper™
November 2005
To import Control Points from a text file press the Import Control button.
The following dialog box will be shown:
Browse for the text file with the list of control points. The text file should consist of one
control point per line in the following format:
PointID X Y Z
The program will count the number of control points entered. Press the OK button when
the routine is finished importing the numbers.
When you are finished entering Control Points, you can go on to create a single
orthophoto. Be sure that the Green Icon appears, indicating that you have a consistent
single space resection solution. Examine the RMS for both the Rows and Columns. You
should reduce these to less than 1.0 for a good solution.
If you wish use the built in bundle adjustment within OrthoMapper (for orthophoto
mosaics), you must put in Tie points at this menu before exiting.
To enter Tie Points, press the Measure Tie Points button.
When this button is pressed, the dialog box changes to that displayed on the next page.
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OrthoMapper™
November 2005
To add a Tie points (sometimes called Pass points), click on the upper low-resolution
image with the right button, then click on the desired location in the high-resolution
image with the right button. No need to press the Measure Point button on the dialog
box. You should choose points in the scene that are distinct. Corner edges are the best
choice. You enter a line of points perpendicular to the direction of flight. It is also
desirable to add a line of point along the bottom and top of the image, if there are
additional strips of image to the top and/or bottom of the image. When you make an
orthomosaic, these points will be matched to adjacent images and a bundle adjustment
(AT) will use these points to give you the best possible mosaic.
In order for this feature to work properly, all images must be scanned
with the data strip oriented on the left or right side. A reasonable
policy is to scan your imagery with the data strip always on the left
side of the imagery.
34
OrthoMapper™
4.0
November 2005
PRODUCING ORTHOPHOTOS
Orthophotos can be produced from any set of oriented photographs with a corresponding
DEM; the user can import a DEM into the program using the Utilities Menu. In all cases,
the image from which the user wishes to construct the orthophotos must be in a project,
and Oriented (both interior and exterior orientation finished).
A digital orthophoto can be produced for any portion of the original image for which a
DEM exists. In addition, a composite orthophoto can be produced from several projects
within an Area Directory. The extent for the orthophoto can be indicated either by
entering the upper left and lower right ground coordinates or by indicating a rectangle on
an image displayed on the screen. The user can choose to use either bilinear or bicubic
sampling to determine the radiometric values for the digital orthophoto. The user can
choose the ground distance between pixels on the digital orthophoto. The digital
orthophoto is produced using a standard procedure: the X, Y for every pixel are known;
the elevation for each pixel is determined from the DEM, and the collinearity equations
are used to interpolate the radiometric value for the pixel from the original digital images
in the project.
To produce orthophoto(s), click on the ORTHO button on the Main Menu.
A dialog box is displayed to allow the user to choose a number of options.
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OrthoMapper™
November 2005
If you are only making an orthophoto from a single image, there should be no need to
choose any of the options within the dialog box. Just press the “Next” button and you
will be able to choose parameters for the orthophoto. This is described in Section 4.2.
If you wish to create an orthophoto mosaic, you will need to choose the additional images
as well as the type of mosaic and optional block adjustment.
The steps necessary to create an orthophoto mosaic are:
1.
Enter the number of images that will be used to create the mosaic. Each of these
images must be already in OrthoMapper projects and have been oriented.
2.
Add additional images by pressing the “Add Images” button.
To Add an image, you must add the project which contains the image.
OrthoMapper needs the project information associated with the image to be
added as well as the image name. Thus to Add an image, you browse to look for
the project with the same name as the image you wish to add and then Add the
project.
3.
After you have added all the images (projects) needed from the mosaic, you can
choose one of the six different methods of making the orthophotos. These choices
are chosen using the three check boxes on the left of the dialog box. The title box
under the options will indicate the choice you have made.
Method 1:
Create Single Orthophotos
This option will produce orthophotos from each individual image. You can
mosaic them later with your choice of mosaic methods. This option has the most
flexibility in the mosaic processing. The orientation parameters from the
individual projects will be used to create the individual orthophotos. The main
reason to use this option is to later use the manual mosaic method in which you
can choose the location of the seam line. Use this method in urban or other areas
in which you would want to choose the seam lines within the mosaic. Method 4
should be used in place of Method 1 when a Bundle Adjustment can be used.
Boxes checked for Method 1
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OrthoMapper™
Method 2:
November 2005
Create a Simple Mosaic
This option will create the mosaic using the orientation parameters calculated
when you oriented each individual image. The mosaic line between the
individual images will be a line half way between the centers of individual
images. You will have few additional choices at the next menu. The check boxes
should look like the following for this option. You must enter a name for the
mosaic in the edit box below the check boxes. This is the quickest, but least
precise method of producing orthophoto mosaics.
Boxes checked for Method 2
Method 3:
Create an Adjusted Simple Mosaic
This option will create the mosaic using orientation parameters calculated using a
bundle adjustment. The seam lines for the mosaic will be as in Method 2. There
must be at least 60% forward lap for each strip of imagery and you must enter Tie
Points within each image during the orientation procedure. The name for the
mosaic must be entered in the edit box beneath the check boxes. The check boxes
should look like the following for this option. A Bundle Adjustment will always
produce better mosaics than using the orientation parameters from the individual
projects.
Boxes checked for Method 3
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OrthoMapper™
Method 4:
November 2005
Create Adjusted Single Orthophotos
This option is similar to Method 1 except the orientation parameters used to
create the individual orthophotos will be derived from a Bundle Adjustment. The
same limitations as described in Method 3 are present for this option. This option
will give you the most flexibility and best overall mosaic if you need to manually
choose the seam lines. This option only differs from Method 1 in that a Bundle
Adjustment is used.
Boxes checked for Method 4
Method 5:
Create a Mosaic from Single Orthophotos
This option will first produce single orthophotos from each individual image and
then automatically create a color-balanced mosaic. The orientation parameters
from the individual image projects will be used to create the individual
orthophotos. This method will produce the best mosaic without a bundle
adjustment.
Boxes checked for Method 5
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OrthoMapper™
Method 6:
November 2005
Create an Adjusted Color Balanced Mosaic
This option will first produce single orthophotos from each individual image and
then automatically create a color-balanced mosaic. The orientation parameters
from a Bundle Adjustment will be used to create the individual orthophotos. This
option will produce the best mosaic whenever manual determination of seam lines
is not desired.
Boxes checked for Method 6
Below is a portion of the screen, showing the appearance of the Orthophoto selection
dialog box for a two-photo block. The user has indicated that an Orthophoto Mosaic is to
be produced by first creating single orthophotos from each image and OrthoMapper
should automatically orient the block. The name for the project and mosaic will need to
be chosen before the “Next” key is pressed.
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OrthoMapper™
November 2005
Method 6 is the option chosen to construct the orthophoto mosaic. This is the best option
to choose in a rural area if a bundle adjustment can be run.
There is a little interaction necessary for the bundle adjustment used during the
automated orientation procedure. This interaction is detailed in the next section 4.1
entitled “Automated Block Adjustment within OrthoMapper”.
The only other option at this menu is to choose to “Transform Overlays registered to
Image”. This option is designed to transform associated line files that can be registered
to the aerial image. The procedure is explained in Appendix C.
After all of the options are chosen at the Image/DEM Selection dialog box, press the
“Next” button. This action will allow you to select the image parameters for the
orthophoto to be produced – see section 4.2.
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OrthoMapper™
4.1
November 2005
AUTOMATED BUNDLE ADJUSTMENT
The Automated Bundle Adjustment is one of the most sophisticated portions of
OrthoMapper. This procedure will automatically find all control points and tie points
measured on any image and transfer them to all other images within the block.
OrthoMapper uses matching techniques to do this task. The success will be dependent
on the image quality, but if well-defined points on the individual images are chosen, the
process is generally successful. After matching all of the points measured by the user,
the program will perform a rigorously correct simultaneous bundle adjustment of the
block of photos, deriving the orientation parameters. This procedure will produce the
best possible orthophoto from the control used to orient the individual images. This
option can be selected at the ORTHO menu as well as the “Automated
Aerotriangulation” entry after pressing the “Orientation” entry from the Main Menu bar.
The order in which the images are entered is important within the OrthoMapper bundle
adjustment for it to work properly. The steps to accomplish an Automated Bundle
Adjustment are as follows:
1)
2)
It is suggested that the image names be entered on the previous menu by using the
Add Image List button.
a)
Create a text file using the windows NOTEPAD program which contains a
list of the images from which you wish to create the mosaic. Each image
file name must be on a separate line and must consist of the full path name
for the file. The file names should be in strip order. This means that the
first name in the file should be image 1 on strip 1, then image 2 on strip1,
continuing until all the images in strip 1 are entered. Then enter image 1
on strip2, image2 on strip2, etc.
b)
Select one of the project files or images using the Browse button. This
will allow OrthoMapper to find the directory for the images.
c)
Click on the Add Image List button, browsing for the image list file you
created in step a) above.
Enter the information about the image block at the Strip Ordering Menu. This
menu requires you to enter the configuration of the images within your block of
images. You will need to enter the number of strips and the number of images
within each of the strips. You will then be asked to enter the image names in
order within each strip. The Strip Ordering Menu as first displayed is reproduced
on the next page.
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OrthoMapper™
November 2005
In this example, there are 21 images within the block.
a)
b)
c)
d)
Enter the Number of Strips within the block and the Number of Images for
Strip 1. Then press the Next Strip button.
Then enter the number of Images in Strip 2 and press the Next Strip
button.
Continue in this fashion until you have designated the number of images
in each strip. If you make a mistake, press the Start Over button to begin
over.
When you are finished, enter the strip/image information, press the Enter
Image Names within Strips button.
The example block described herein is made up of 3 strips of 7 images in each strip.
After clicking on the Enter Image Names within Strips button, the menu will change as
displayed on the next page.
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OrthoMapper™
November 2005
The images you entered at the previous menu will appear in the list on the left of the
image. You are now expected to tell the program the order of the images within each
strip. If you followed the suggestions given on the last page, the image will be in order
and you will only need to press the Add an Image button for each image.
To add an image name to the Images within the Strips:
a)
Select an image in the list on the left of the menu using the Left Mouse
button. You must select the file name for Strip and Image number
displayed in the two boxes on the right side of the menu. In the above
example, the user has selected a file name for Strip 1, Image 4.
b)
Press the Add an Image button.
When you have added the last image in a strip, the strip index automatically changes and
allows you to add images for the next strip.
Carefully review the images in the list on the right side of the menu to be sure that they
are in the proper strip order. All of the images in strip 1 are followed by all the images in
strip 2. The images within each strip should be in order from left to right. When you are
satisfied with ordering, click on the OK button.
The matching procedure will then be initiated.
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OrthoMapper™
November 2005
When the matching algorithms are finished, the following menu is displayed.
This menu allows you to display the AutoOrient Log, Set the Initial Weights for the
bundle adjustment, and run either the built in Bundle Adjustment or the optional AeroSys
Bundle Adjustment.
You should examine the AutoOrient Log to verify that enough points have been matched
between the images. There must be at least 6 to 10 points matched for adjacent images.
If the images are in different strips, three to 6 points should be matched. If an insufficient
number of points are matched, the bundle adjustment will fail.
The most important point is that there must be at least 6 to 10 common TIE and/or
Control points between adjacent images. A summary of the number of common points
between the images within the block can be found at the bottom of the AutoAdjust.Log
file. Below is the example project in first tutorial in Appendix A.
Listing of Common Tie and Control Points for each image
Between GL_820.LAN:
And GL_821.LAN --- 25 Tie Points and 9 Control Points
Between GL_821.LAN:
And GL_820.LAN --- 25 Tie Points and 9 Control Points
If only a few points are transferred between the images, the tie points could be located in
the incorrect positions.
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OrthoMapper™
November 2005
Densify Points
Before proceeding, you should click on the “Densify Points” button. This option will
allow you to check each tie point and, more importantly, add tie points to images missed
by the matching algorithm. After clicking on the Densify Points button the following is
displayed on your screen:
The menu at the upper left allows you to select the image and point to be edited. The
image on the bottom left is the image on which the tie point was entered. The image on
the bottom right is one of the images on which this point may have been transferred. The
list at the upper right of the screen lists all points not transferred.
This option will allow you to examine each tie point and be sure that it has been
transferred to the proper location.
The upper left drop down Image Name menu allows you to choose the image on which
the tie points are going to be examined. Within each image there will be a number of Tie
Points to be checked. An individual point on an image can be selected by choosing its
Point Number from the drop down menu below the Image Name menu.
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OrthoMapper™
November 2005
The image names displayed in the “Other Image on Which Point may be Located” are all
of the images on which the points displayed on the left image are located. You can
choose the image displayed on the lower right by clicking on the image name in the list
box.
The Green cross on the Left Image is positioned at the location you entered for
the point.
The Green cross on the Right Image is located at the predicted location for the
point on the Left Image.
The Magenta cross on either image is at the location of the point as transferred by
the matching algorithm. The Magenta cross is the position of the point that will
be used in further processing.
There are a number of buttons on the left side of the menu.
Next Point -Delete Second Point -Delete Points -Next Image --
This button will allow you to examine the next Tie point
in the project. Clicking on this button at the last point in
an image will automatically select the next image.
This option will delete the Tie point from the image
selected in the List Box
This option will allow you to delete the Tie point from all
of the images.
This option will allow you to go on to the next image in
the project.
You do not need to check every point in a large project, but as a minimum, you should
choose all points that are listed in the upper right list and locate the tie point on each of
the images. If a point cannot be located on an image, you can move the point on the left
image so it can be located on the right image. You must be sure that if you change the
location of a tie point on the left image, you have located it correctly on all of the images
in the “Other Images .. “ list box .
When you are finished, you can click on the “Finished” button.
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OrthoMapper™
November 2005
Set Initial Weights
The default option of “Automatically delete Tie and Control Points …” should be used
unless you have had problems with a previous bundle adjustment on these images. In
general, in almost all cases, if one chooses “Run Initial Adjustment without weights” will
result in an adjustment. It is recommended that you also click on the “Display Progress
after each Adjustment”. If you choose these options, you will need to manually delete
poor Tie and Control points at the Bundle Adjustment Weights Menu.
The default weights for the bundle adjustment are set for the visual orientation method.
If you are using ground control points to orient your images, you should click on the Set
Initial Wts button. The menu below will appear.
The weights for the Ground Coordinates should be set to the uncertainty in your ground
control measurements. For GPS control, these numbers are likely to be a 0.1 meters or
smaller. The Photo Coordinates uncertainty can be left as the default, or set smaller to
about ¾ of a pixel. The Camera Coordinates should not be changed unless the
photography as been flown using an INS/IMU. In this latter case, you should set all the
values to 1’s.
This menu can also be used to set Visual Control points to check points. This will
eliminate them from the bundle adjustment solution. If you do this, you must import a
number of physically measured ground control points so that the solution will converge.
Using this technique, you can use OrthoMapper to enter your pass points and then
eliminate the visual control to arrive at a solution as good as that entered using a full
softcopy workstation.
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OrthoMapper™
November 2005
Method to use Visual Control as Check Points
In general, the method to arrive at the best possible bundle adjustment is the following:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Orient your images using Visual Orientation.
Enter pass points on each of the images.
Run a bundle adjustment and eliminate any bad pass points.
Enter the physical ground control points in the individual projects.
Go the Utilities menu and choose to run a bundle adjustment.
Choose to set the Initial Weights button (this menu).
Click on the check box to set the Visual Control as check points.
Click on the check box to Import Ground Control from projects.
Set the weights appropriately for the Ground Coordinates.
Run the bundle adjustment.
After clicking on the OK button at this menu and then clicking on one of the RUN
buttons at the previous menu, OrthoMapper will run a bundle adjustment. When the
bundle adjustment finishes, the following menu will be displayed.
At this menu, you are expected to modify the weights assigned until the Standard
Deviation of Unit Weight is close to 1.0. If the ChiSquare Test box has a green circle
displayed, you may proceed to make the orthophoto.
In the case of the menu displayed above, you should change the Uncertainty for the Photo
Coordinates to about 6 for both the Tie Points and Control Points. If you do this, the
following menu will appear.
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OrthoMapper™
November 2005
The ChiSquare Test indicates that you are finished and can go on and make your
orthophoto.
The bundle adjustment is an iterative process. You may need to go to the Advance
Options to change some of the weights used by the bundle adjustment. The Advanced
Options menu allows you to change the individual weights for the ground control, the
weights used on the camera locations and orientations as well as the ground weights for
the tie points. By pressing the Delete Tie/Control Points button you can examine the
bundle adjustment log and delete Tie and Control points with large residuals. The Delete
Tie/Control Points Menu and the Advanced Options Menu are displayed on the next
page.
The file <projectfile>_BlkAdj.log is a report from a successful block adjustment. The
user can examine this report to have an indication of the accuracy of the block
adjustment. The orthophoto produced using this block adjustment may match better to
the control than the report indicates, due to the procedure of distributing the errors
throughout the orthophoto.
After the ChiSquare Test displays a Green Icon, you can press the “Make Orthophoto”
or press the “Quit & Save Orientation”. If you wish to make individual orthophotos of
the images in the project, it is recommended that you press the “Quit & Save
Orientation” button as this will allow you the most flexibility in choosing which
individual images are used to create orthophotos.
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OrthoMapper™
November 2005
Adjust/Delete Tie Points
If you are running a multiphoto bundle adjustment, it would be a good polity to adjust
some of the Tie points to reduce the standard deviations. Press the “Adjust Tie/Control
Pts” button.
At the Point Delete-Editing Menu you will be able to move pass/tie points so that they
correspond on the same place on each of the images on which they appear. You can also
delete any point from an image or delete the point from all of the images (effectively
deleting the point from the project).
The Menu at the left allows control of the process. The Number of Points that have large
residuals is displayed just after the text. The next line displays the current point that the
user is editing. The points are sorted in order from the largest residual to smallest
residual. The point number as well as the point name is displayed on the line. The point
location – its strip and image number as well as the residual in columns and rows is also
displayed.
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OrthoMapper™
November 2005
In the list box below this line are all of the other images on which this particular pass/tie
point has been measured.
The image at the top right of the screen is the image in which the point being edited is
displayed. The image at the bottom right of the screen is the image selected in the list
box within the Point Delete-Editing Menu.
Within each of the images, there are two colored crosses. The orange cross in both
images shows the current position of the measured point. In the top image, the green
cross shows the position of the point predicted from an adjusted ground coordinate. On
the bottom image, the green cross is the predicted corresponding point from the orange
cross on the top image. If you change the position of the measured point on the top
image, the corresponding point will change on the bottom image.
There are 4 buttons on the left of the Point Delete-Editing Menu.
Next Point button – This button will allow you to edit the next point in the list. Press
this button after you have changed the position for the point on all of the images on
which it is measured.
Delete Point button – This button will delete the point being edited from the project.
The point will not be deleted from any other image. Use this button very carefully.
Delete Other Pt button – This button will delete the point from the image high-lighted in
the list box. The point will only be deleted from this image. One would want to use this
button if the point is easily located on most of the images, but not on one particular
image. Instead of deleting a point, the user should consider moving the position of the
pass/tie point so that it is visible on all of the images indicated in the menu.
Delete Pt on All Images – This button will remove the pass/tie point from all of the
images within the project. One should use this button if it is found that you have multiple
points at the same location. The bundle adjustment solution is not appreciably helped if
there are a large number of pass points at the same location with differing numbers.
Each of the images can be zoomed in or out using the mouse wheel or the Alt/ Mouse
Button combination.
On the top image, a point measurement is made using the Right Mouse button.
On the bottom image a point measurement is made using the Right Mouse button or the
S key.
Below is an example of moving the point on the top image to a recognizable point. Note
the green cross on the bottom image.
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OrthoMapper™
November 2005
After measuring the point on the bottom image, you should then select the next image
from the list box by clicking the Left Mouse button on the image name in the box.
Measure the corresponding point on this and all of the remaining images displayed in the
list box.
Press the Next Point button to edit the next point.
When the last point is edited, the program will return to the previous menu.
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OrthoMapper™
November 2005
If for some reason too many points have been deleted, the bundle adjustment will not
converge. The button,:”Restore Previous Project” will allow the user to choose one of
up to 9 previous projects to continue the analysis.
Advanced Menu for Controlling the Bundle Adjustment
By clicking on the Advanced Options button at the Bundle Adjustment Weight Menu, the
Advanced Menu for controlling the Bundle Adjustment will be displayed.
Sometimes you might want to change the weights assigned to the Tie Point ground
coordinates. The Advanced Menu will allow you to do this task. You should only do
this if you have a very good reason (knowledge) of the expected variation for these
parameters. The other task you can do at this menu is to change the weights for
individual ground control points. You should only change the weights for physical
ground coordinates, not Visual Control points.
If the block adjustment fails, you must go back and reenter additional points (both control
and tie points). The procedure will only fail if an insufficient number of points have been
matched between the photos within the block.
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OrthoMapper™
4.2
November 2005
SELECT IMAGE PARAMETERS FOR THE ORTHOPHOTO
The dialog box for selecting image parameters for the orthophoto is the following:
The default coordinates will create the maximum size for the Orthophoto. The Ground
Pixel size is only an approximation; the user should set this number.
If you are using a color image, you will be given a choice of using one band or all of the
bands as well as the ordering of the bands. These parameters can be changed in the
Orthophoto Color Bands section of the dialog box.
If you wish to make only a portion of the maximum sized orthophoto, you can choose
“Visual Subset” button. This choice will allow you to choose the portion of a single
image to be used to make the orthophoto.
The “Fit Orthophoto to Control” allow you to choose between two stretches that can be
performed after the orthophoto is produced. These stretches will distribute any spatial
errors produced in the orthophoto throughout the final orthophoto product. THIS
OPTION SHOULD ONLY BE USED FOR CREATING ORTHOPHOTOS FROM
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OrthoMapper™
November 2005
INDIVIDUAL PROJECTS. DO NOT CHECK ANY OF THESE OPTIONS FOR
PROJECTS CREATED WITH THE BUNDLE ADJUSTMENT.
“Create Orthophoto(s) with minimum border pixels” will allow one to create an
orthophoto without most of the usual black surrounding the image. This option is
designed for subsequent use of the automatic mosaic routine.
“Create Orthophoto(s) with no border pixels” will reduce the size of the orthophoto even
more than the above option, leaving no border pixels at all – useful for tiling.
“Delete LAN files after producing orthophotos” will cause OrthoMapper to delete the
LAN version of the original images after the orthophoto is produced. The LAN
files will only be deleted if the TIF version is present in the same directory.
“BiCubic Interpolation” will allow one to create the orthophoto using a BiCubic
interpolation instead of the default method – BiLinear Interpolation. BiCubic
Interpolation produces a sharper orthophoto, but needs additional time.
If the user chooses to create Single Orthophotos, the menu appears a little different:
The directory in which to produce the orthophotos is displayed at the top of the menu. If
a mosaic was indicated at the first Orthophoto menu, then the “Create orthophoto(s) with
minimum border pixels” will automatically be checked.
You will also be given an option of correcting the imagery for uneven illumination by
checking the box “Radiometric Correction/Normalize”.
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OrthoMapper™
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If projection information is desired, the “Add Projection Information to Orthophoto(s)”
must be checked. After checking this box, the user is expected to choose the Coordinate
System and Projection for the orthophoto(s). The projection information will be stored in
the GeoTIFF header of the orthophoto(s) created.
If you would like to create Flicker Images for quality control, check the box entitled
“Create Flicker Images” and set the path in which to create the flicker images. This
option will only work if visual orientation has bee used in the project.
Batch Processing
You can save all of your settings to make orthophotos for batch processing later, by
either Starting a new queue (Press the Start Button) or Adding to an existing queue
(Press the Add Button). This will allow you make your orthophotos (and any overlays)
during the evening when no one is using your computer. Any number of orthophoto
projects can be added to a queue. To start processing a queue, go to the OrthoMapper
main menu and choose the “Start Batch Orthophoto Process” option.
Use the Browse button to find the existing batch processing queue file. The file will have
an extension of .QUE. After the file has been loaded, press the OK key. OrthoMapper
exit from the Select Orthophoto Output Parameters dialog box and return to the main
menu.
Creating an Orthophoto
When you are satisfied with the entries in the Select Orthophoto Output Parameters
dialog box, press the Create Ortho button. The orthophoto will then be produced.
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OrthoMapper™
4.3
November 2005
CREATING MOSAICS FROM LARGE COLOR IMAGES
If you are faced with the task of creating an orthophoto mosaic from a number of large
color images that are greater than 600 megabytes each, you might want to consider
transforming the images into panchromatic images first. This tactic will allow you to
save time during Interior Orientation and during the matching and editing points during a
bundle adjustment.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Go to the File Conversion option on the Utilities menu and choose Create
LAN/DEM for TIF/IMG files.
Be sure all the TIF images you need in the project are in the same directory.
Choose one of the files using the Browse button.
If you have chosen a color image, the following menu will appear. Check the box
to Convert to a 1-band PC LAN file.
When you create your projects, use the PC files created. These are files with
character strip “_PC” appended to the image name (before the .LAN).
Proceed with adding control and pass points to the project and finish your bundle
adjustment.
When you are ready to make your orthophotos, return to the File Conversion
menu above and create the LANs from the TIF files, but this time DO NOT check
the Convert to 1-band PC LAN file box. You can delete the PC files.
When the conversion is complete, go to the Main Menu of OrthoMapper and click
on “Orthophoto”. Click on “Change PC Image Names”.
Open your project that you created during the bundle adjustment. The image
names within the project will be changed to the names of the color images.
Create your orthophotos as you wish.
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OrthoMapper™
5.0
November 2005
IMAGE DISPLAY
There are five options under the Image Display Menu. These options allow you to
display aerial images, orthophotos, and DEMs. The five options are:
5.1
READ
This option opens an image or DEM and reads it into the memory of the computer.
An image cannot be displayed until it is read into the memory of your computer.
The read function recognizes a wide variety of image formats.
After clicking on the Read button the standard Windows Browse Dialog Box is
displayed for you to choose the file.
If the file is successfully brought into memory, a panchromatic image will be
displayed immediately. A color image will show the Display dialog box.
5.2
DISPLAY
If an image is already in memory you can choose to Display it. The Display dialog
box is shown only when you are displaying a multi-band image.
The default choice for a black and white image is Single Band. Under the Band
Choice section there will be a check box for each band in the image. You can
display one or all of the bands (as individual images on the screen) by checking the
boxes.
If you have read in a color image, you can choose to display a false color composite
of the image. The “3 Band Combination” button will be the default for a color
image. You can optionally choose the how to assign the Red, Blue, and Green to
the bands in the image.
The bands in the multi-band image are chosen by selecting numbers in the pull
down boxes to the right of titles “Red Band”, “Green Band” and “Blue Band”.
The initial Enhancement for the display can also be chosen at this time.
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OrthoMapper™
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Once an image is displayed, you can zoom in, zoom out, change the enhancement
or quit. To change the screen resolution of the image, you can use the menus at the
top of the display, use the keyboard ( Zoom In – Alt/Left Mouse Button; Zoom Out
– Alt/Right Mouse Button), or the Mouse Wheel.
5.3
FLICKER/SPLIT WINDOW
This Image Display menu option is designed to compare an existing orthophoto
image to an orthophoto created with OrthoMapper. This display can also be used
for land use change detection between orthophotos from two different dates. You
cannot “Read” an image into memory before using the Flicker Option. This option
will read up to eight images into memory.
You will be asked for file names of a Base Image and up to 7 additional images.
All images must have coordinates (a DRG, DEM or an orthophoto) or all images
must be exactly the same size. If one of the images is a DRG or DEM, it must be
the Base Image.
The images will be read into memory and then resampled into the same coordinate
system so that pixels from the two images with the same coordinate are displayed at
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OrthoMapper™
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One of the options on the menu is to save the resampled images for quick recall. If
one clicks on the check box “Save Flicker Images” the program will save a copy of
the resampled images to your disk drive. Then if you want to examine the two
images again, the time to load them into memory will be greatly reduced. The
resampled images will be saved to your disk using the image file names with the
string _Flk added.
An image will be displayed and a dialog box will be to the right of the window.
You will be able to:
1.
2.
3.
4.
Flicker between the Base Image and the Second Image by pressing the F
key.
Swipe between the Base Image and the Second Image along a vertical line by
pressing the V key.
Swipe between the Base Image and the Second Image along a horizontal line
by pressing the H key.
Add a number of shape overlay files to be display during the above operations
(produced in ArcView).
Each of these processes will be illustrated below.
You must select the Flicker Window by clicking on it with the Left Mouse Button
before pressing the F , V , or H keys.
Pressing F while you are in the Flicker Mode will allow you to rapidly switch between
the two images in memory. Below is an orthophoto made using OrthoMapper using a
1962 paper print of the same area as the 1992 orthophoto displayed on the last page.
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OrthoMapper™
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By pressing either V or H you can view both images on the screen at the same time.
These are called the Swipe Modes. The V will split the two images with a vertical
break, and the H command will split the two images with a horizontal break. The break
line can be moved within the image by dragging the line with the Left Button on the
mouse. Examples of each can be seen below:
This technique can be a very sophisticated tool for change detection. In this
particular case it is easy to observe the difference in the shoreline (on the right) that
has moved more then 15 meters to the West over a 30-year time span. Note the
road on the left side of the image (dark pavement on the top image, light gravel on
the lower image) is at the same spatial location on the two dates.
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November 2005
Shoreline
Road
Water
Water
The upper half of this window is the 1992 orthophoto and the lower half of the
image is an orthophoto created from a 1962 paper print by OrthoMapper.
To switch back from either of the Swipe Modes to the Flicker Mode, press N
To close the Flicker Window, use the “Close” button on the dialog box.
In order to display Shape overlay files on the Flicker/Swipe window, you must click on
the “Add Shape files to display” check box when specifying the images, as below:
After the Flicker/Swipe window is displayed, a different dialog box is displayed:
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OrthoMapper™
November 2005
The button on the dialog box “Load a Shape Set” allows one to load Shape Overlay files
into the program. In the above example, two Shape files have been loaded. To display
the Shape Files, the check box next to the name should be checked as shown below.
Each of the Shape file data will be displayed in a different color. The overlays will be
displayed in all of the flicker/swipe images.
To close the Flicker/Swipe window, press the Close button on the dialog box.
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SaveAs
This option within the Display Menu will allow you to change the format of the
image being saved. With this option it is possible to change .LAN files to .TIF
files or the reverse. When the SaveAs option is chosen, you will be asked to
choose the image to be saved and the extension. Choose the extension from the list
as well as typing in the extension at the end of the file name.
In this case the user is asking for the file loaded in memory,
H_YAHARA\3ccR_286.lan should be changed to a TIFF file. The user should
also change the .lan extension on the file name to .tif before pressing the “Save”
button.
5.5
CLOSE
This option will unload an image that has been loaded into memory. You should
unload any image that you are no longer interested in viewing. The memory can be
used for other functions. If there are more than one image in memory, you will be
give a chance to designate which image you wish to close.
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November 2005
Enhance
When an image is displayed, an Enhance option is on the task bar of the window as
shown below:
After clicking on the Enhance option, the options detailed in section 6.1 will be displayed
as well as three additional options.
Negative LUT
This option allows the user to display the dark values in an image as bight values and the
bright values in an image as dark values. This is particularly useful for finding paneled
control points in a light image.
Brightness/Contrast LUT
This option allows the user to accomplish a non-linear stretch by setting the contrast and
brightness for the display. This option is useful in cases where the image has
disproportionate amounts of dark and light sections. This option is used in conjunction
with the control at the bottom of the menu (Adjust Brightness/Contrast).
Manual Stretch LUT
This option allows the user to set the minimum and maximum values used for the linear
stretch. This option is used in conjunction with the control at the bottom of the menu
(Adjust Manual Stretch).
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Above is an example of a line stretch LUT determined automatically. A more optimal
display will result if the user clicks on 45 for the minimum value and clicks on 240 for
the maximum value as shown below.
.
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6.0
November 2005
UTILITIES
There are 17 standard choices within the Utilities Menu of OrthoMapper
1. Change Display
2. Change/View Image Parameters
Check for Unit Compatibility
3. Change Coordinates
4. File Conversion
Create LAN Files
Convert BIL/BSQ/RAW/USGS DEM File
Convert Compressed JPEG Files
Convert 8-bit image to 1-bit image
Convert for MapSheet Express
5. Import/Mosaic/Create DEMs
Import DEM from Text File
Create DEM from SDTS File
Create DEM from DXF File
Mosaic DEMs
6. Correct Lens Falloff/Sun Angle
7. Orthophoto Mosaic Functions
Update Orthophoto
Manually Create an Orthophoto Mosaic
Automatically Create Orthophoto Mosaic
Subset Orthophotos
MergeFill NoData
8. Change Color/Contrast of an Image
9. Import Exterior Orientation Parameters
10. Rotate Image/Project
11. Subset/Average/Trim an Image/DEM
12. Band-to-Band Registration
13. Bundle Adjustment
14. Create Flicker Images
15. Calculate Stretch Parameter
Manually enter orthophoto stretch
Stretch an Image to Map
16. Measure Point Function
17. Specialized Transformations
Extend DEM
Reorder Bands
Extract one Band
Each of these choices is described below
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CHANGE DEFAULT DISPLAY PARAMETERS
The default method of displaying color images is to display the first band as blue,
the second band as green and the third band as red. This option can be used to
change this default. The default display stretch can also be changed at this menu.
In addition to the previous functions explained, the options under “Matching
Window” will affect the automated block adjustment. The matching algorithm in
the automated block adjustment uses the “Matching Band”. If you decided to
change the “default” be sure to change it before you start to create an orthophoto.
Both the sizes of the Matching Window and Search Distance can be changed within
this option. For very large-scale images, a larger window Size and larger Search
Distances may improve the matching algorithm.
The Default GeoTiff Coordinates option will allow you to set the way OrthoMapper
stores the sign of Y Cell in a GeoTiff file. Programs such as ArcGIS 8.x and Erdas
Imagine require the Y Cell to be positive. ArcView 3.x does not use the Y Cell
value stored in the GeoTiff file; it uses the numbers stored in the World File.
OrthoMapper always sets the Y Cell in the World File as negative – which is
appropriate for ArcView 3.x.
The Y Cell sign can be changed within an existing file by using the “Image
Display” option: 1) Read a file into OrthoMapper, 2) Change the Default GeoTiff
as wanted, and 3) Use the SaveAs option to save the file one your disk (you can use
the same name if desired).
The selections at this menu are saved internally and will be used by OrthoMapper
the next time an image is displayed, even after OrthoMapper has been closed and
reopened.
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Default Display Stretch
The user can choose three different options as to how the Look-Up-Table (LUT) is
constructed to display an image. An LUT is the relationship between the digital
numbers within the image and limited number of colors or gray shades displayed on
the screen.
If the No Stretch option is chosen, there is a one-to-one relationship between the
digital numbers within the image and the gray shades displayed on the screen.
Usually this results in a very dark image, but the coloring and intensity is displayed
in correct proportions.
Both the Linear Stretch and the Histogram Equalization options use the entry in
the % Cut-Off Value box. In both cases, a histogram for each band of a color
image or for one band of a panchromatic image is first calculated. A histogram is a
plot of the number of digital values (pixels) present in an image at each digital
value. A minimum and maximum value for each band in the image is determined
from the histogram based on the value in the Cut-Off Value box.
The Histogram Equalization option will attempt to display the same number of
pixels on the average at each display intensity between the minimum and maximum
values described above. This display option will emphasize features in the image
that consist of relatively fewer pixels. Colored image displayed with this option
will be displayed with uncommon color combinations.
The Linear Stretch option is most usually the option chosen. This option will
display all data in the image between the minimum and maximum values described
above over the full display capabilities of the monitor. If images appear overly
bright the Cut-Off Value should be increased. If images appear overly dark, the
Cut-Off Value should be decreased.
The above options will be used for all images displayed within OrthoMapper.
Occasionally, one might want to change the display option for an individual image,
but not use that new display option on all future images. In these cases, the type of
stretches can be changed when the image is displayed.
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6.2.1 CHANGE/VIEW IMAGE PARAMETERS
This option allows you to view and change the image parameters of an image that
has been loaded into memory. The most important use of this option is to change
the units for an image. Many orthophoto images stored as TIFF files do not store
the units within the file.
If you change anything at this menu, you must then save the file using the SaveAs
option under Image Display.
6.2.2 TEST FOR COMPATIBLE UNITS
This option allows you to check for unit compatibility between two files and if
possible, the unit flag will be changed in the second file to allow overlap of the
coordinates between the files.
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6.3
November 2005
CHANGE COORDINATES
There are a number of different coordinate systems for images and data files that can be
used by OrthoMapper. A few important points should be remembered.
1.
2.
The orthophotos produced by OrthoMapper will have the same coordinate system as
the control points used to orient the image.
For the Visual Orientation to work properly, the existing orthophoto and DEM must
have the same coordinate system.
If the files you are using to produce your orthophoto are not in the desired coordinate
system, then this option can be used to produce a new image, DEM, or shape file with
the desired coordinate system. A shape file is a vector file used by a number of programs
such as ArcView.
The option can also be used to transform individual coordinates from one coordinate
system to another.
When the Change Coordinates option is chosen, the following dialog box is displayed:
The four options within this dialog box are chosen in the small function box at the upper
right corner and are:
1.
2.
3.
4.
5.
Interactive Point Calculation
Text file of Points.
Transform Shape File.
Resample Individual Image/DEM
Resample Multiple Images/DEMs
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The second option allows one to transform a file of control points. For the third and
fourth options, you are expected to enter an existing file name and the file name for the
new transformed data. For the fifth option, you can choose up to 100+ files to transform
at the same time.
For all of the options, the current coordinate system and target coordinate system must be
chosen.
1.
2.
3.
Choose the current coordinate system and projection for data in the existing file.
Choose the coordinate system and projection for the file to be created.
Change the units for the target coordinates if desired. Do not change the units for the
existing data unless you are sure that the default is wrong.
The Coordinate System and Projection are chosen by clicking on the down arrow at the
right of each edit box.
On the next pages are descriptions of each of the Function Options for the Change
Coordinates Feature.
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Option 1: Interactive Point Calculation
If you wish to calculate the position of an individual point in a different coordinate
system and/or projection, click on the second option in the box at the upper right of the
dialog box.
When Interactive Point Calculation is chosen, the dialog box changes to allow you to
enter point values.
The coordinate system and project must be chosen as described above. The dialog box
changes as depicted on the next page.
You are expected to enter a set of coordinates (X, Y) in the lower left edit boxes and
press the right arrow beneath these boxes. The dialog box should display the Longitude
and Latitude of the coordinates in both coordinate systems and the new X,Y coordinates.
Pressing the buttons beneath any of the four pairs of coordinates will cause the program
to transform those coordinates.
Option 2: Text file of Points
This option allows you to transform a file of points, such as ground control points,
between different projections. The text file must have one of the three acceptable
formats. There must only be lines with the coordinates – no extra lines at the beginning
of the file
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.
1. X Y <CR> -- coordinates, separated by a space and one set of coordinates per
line. The <CR> stands for a Carriage Return
2. PtID X Y <CR> -- The PtID can be up to 8 characters
3. PtID X Y Z <CR> ( the Z must be a number and will just be copied to the
output file).
Option 3: Transform Shape Files
This option will allow you to transform ArcView shape files from one coordinate system
to another. You can only enter one file at a time. But you can add the file into a batch
Que and transform a number of files at one time.
If this option is chosen, the dialog box below is displayed:
The name for the shape file must be entered in the first edit box. An output file name
must be entered in the second edit box. The Current Coordinate System and Target
Coordinate System must then be entered.
Note that if you want to add this transformation into a batch Que for processing later,
the “Save” button on the bottom right can be pressed.
Otherwise, to transform the shape file, just press the “OK” button on the bottom of
the dialog box.
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Option 4: Resample Individual Image/DEM
This option will allow you to transform an individual Image or DEM from one
coordinate system to another. You can only enter one file at a time, but you can enter
the file into a batch Que for processing later.
After choosing this option, the following dialog box will appear:
The name for the image file must be entered in the first edit box. An output file name
must be entered in the second edit box. The Current Coordinate System and Target
Coordinate System must then be entered.
Note that if you want to add this transformation into a batch Que for processing later,
the “Save” button on the bottom right can be pressed.
Otherwise, to transform the image file, just press the “OK” button on the bottom of
the dialog box.
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Option 5: Resample Multiple Images/DEMs
If this option is chosen, coordinated systems for up to 100 (or more) images can be
transformed at one time. Any file that OrthoMapper can read can be transformed using
this option. If in doubt, just try to read the file in question using the “Display Image”
option. A limitation for this option is that all of the images you are transforming must
have the same extension (i.e., they must all be .TIF, .BIL, or .LAN). The output file
name will have an extension of .TIF unless the input file name extension is .LAN. If
Option 5 is chosen, the dialog box will appear as below:
The images to transform are selected in the “Images Selected” box by using the
corresponding “Browse” button. After choosing the “Browse” button, one can choose
the directory and then choose a file by pressing Ctrl/Left Mouse Button. Any number
of images can be chosen this way.
After selecting the images, the output directory must be chosen. Again, the
corresponding “Browse” button should be used to choose the output directory. All of the
transformed images will be created in this directory.
An optional name extension can be entered in the edit box to the right of the title “Name
Extend”. This option will add up to 8 characters to the end of each of the input images
names to create the output image name. For example, you might want to transform a set
of files from NAD27 to NAD83. You could add the string “_NAD83” in the Name
Extend edit box. If an input name was “Baker.BIL” the output name would be
“Baker_NAD83.TIF”
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6.4 FILE CONVERSION
6.4.1
CREATE LAN/DEM from TIF/IMG
The suite of routines in this option allows you to convert files with a number of
different formats, including MrSid format into .LAN or .DEM files.
OrthoMapper should create LAN files whenever this format is needed, but you
may be able to optimize a production procedure by converting a large number of
files to LAN format at the beginning of your procedures. This option will also
allow you to create 1-band panchromatic images from color or color-IR images to
save processing time during a bundle adjustment. Another option allows you to
convert 16-bit images to 8-bit images.
After choosing this option, the following dialog box will be displayed:
The user is expected to Browse for the name of the file to convert. Three options
on the menu allow you to convert all similar files within the directory into LAN
files, delete the original files after conversion, convert files to DEMs, or rotate the
files. If the image you choose is a color or color-IR image, you will be given an
option to create a 1-band LAN.
Creating orthophotos from large color images
If you are faced with the task of creating an orthophoto mosaic from a number of
large color images that are greater than 600 megabytes each, you might want to
consider transforming the images into panchromatic images first. This tactic will
allow you to save time during Interior Orientation and during the matching and
editing points during a bundle adjustment.
1. Go to the File Conversion option on the Utilities menu and choose Create
LAN/DEM for TIF/IMG files.
2. Be sure all the TIF images you need in the project are in the same directory.
Choose one of the files using the Browse button.
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3. If you have chosen a color image, the following menu will appear. Check the
box to Convert to a 1-band PC LAN file.
4. When you create your projects, use the PC files created. These are files with
character strip “_PC” appended to the image name (before the .LAN).
5. Proceed with adding control and pass points to the project and finish your
bundle adjustment.
6. When you are ready to make your orthophotos, return to the File Conversion
menu above and create the LANs from the TIF files, but this time DO NOT
check the Convert to 1-band PC LAN file box. You can delete the PC files.
7. When the conversion is complete, go to the Main Menu of OrthoMapper and
click on “Orthophoto”. Click on “Change PC Image Names”.
8. Open your project that you created during the bundle adjustment. The image
names within the project will be changed to the names of the color images.
9. Create your orthophotos as you wish.
Converting 16-bit images to 8-bit images
There may be times you wish to convert 16-bit images to 8-bit images. To do this
task, click on the check box “Convert to 8-bit LAN” after you have entered a file
name. Click on the OK button. Note that this check box will only appear if you
have selected a 16-bit TIF file.
6.4.2
CONVERT BIL/BSQ/RAW/DEM FILE
This routine will convert a number of file formats into .TIF files. The file formats
this routine will read are:
1.
.BIL files – Band Interleaved
2.
.BSQ files – Band Sequential
3.
.RAW files – Airborne Data Systems image files
4.
.HDR files – ArcView style header files for BIL & BIP files.
5.
.DEM files – Files distributed by USGS with a .DEM extension.
6.
BIL files that are to be converted to DEM files (the National Elevation Data
set);
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If the BIL file is part of the NED data set, click on the check box “Output file is a
DEM”. Go on to section 6.4.2.
Click on the OK button.
If the algorithm is successful, a .TIF (or .DEM) output file will be created and the
Change/View Image dialog box will be displayed (see section 6.2 above).
If the algorithm is not successful, a menu will be displayed which will give you a
chance to enter parameters to read the file.
This dialog box is generally usable for any flat file if you can determine the correct
input parameters.
6.4.3
Converting a BIL to a DEM file (National Elevation Data set)
If the BIL file is to be converted to a DEM, the menu on the next page will be
displayed after entering the OK button.
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You should just press the OK button. A DEM will be created with decimal degrees
as the X,Y units. Before using this file for any orthophoto tasks, you must
transform the file into some map projection using the “Change Coordinates” option
in the Utilities Menu (section 6.3).
6.5
IMPORT/MOSAIC/CREATE DEMs
There are five options within this option.
1.
2.
3.
4.
5.
6.5.1
Import DEM from Text File
Create DEM from SDTS File
Create DEM from DXF File
Mosaic DEMs
Export DEMs
Import DEM from Text File
This option can be used to produce a .DEM file that can be used by OrthoMapper
from a number of different text files. After choosing this option, the dialog box
shown below is displayed.
The data can be either in a regular grid, such as exported from programs like
ArcInfo, or in an irregular set of X,Y,Z points collected from an analytical
plotter.
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6.5.2
November 2005
Regular Array of Points
Be sure that the check box under Type of Data in file, “Points are NOT in a regular
array” is NOT checked.
A file with four different types of elevation data can be imported.
1.
2.
3.
4.
Files with only Z (elevation) data, one value per line.
Files with only Z values, where the Z values are in a two-dimensional array of
Ncols by Nrows (Y can be from high to low or low to high).
Files with X,Y,Z values on each line separated by spaces.
Files with X,Y,Z values on each line separated by commas.
You are expected to enter the ASCII file name for the DEM data. Then choose the
type of data within the file.
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It is important that you correctly check (or not check) the next two boxes. You
must know the units of the Z values within the file. You also must know the units
of the XY coordinates.
The next edit box allows the program to skip a number of lines within the file
before the elevation data. Many files have some type of header information at the
beginning.
The next edit box allows the program to skip characters at the beginning of each
line of data. The default is to skip no characters.
The Starting Coordinates must next be entered. Be sure to indicate if the numbers
entered are relative to the Lower Left of the DEM or the Upper Left of the DEM.
The number of Columns and Rows for the DEM should be entered next. The Rows
are in the North-South direction and the Columns are in the East-West direction.
The distance between cells for the DEM should next be entered. The units will be
the same as those entered for the XY Coordinates entered previously.
The No Data Value is an optional entry. The program will skip any Z values that
equal this value.
The Minimum and Maximum values refer to the Z values in the file. The program
will skip any Z value below the Minimum value and any value greater than the
value entered in the Maximum edit box. The units for Minimum and Maximum are
the same as those entered previously for the Z values in the file.
When you are satisfied with values entered in the dialog box, press the OK Button.
A DEM file will be produced with the same name as the input file but with an
extension of .DEM.
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November 2005
Irregular Array of Points
If you are importing an irregular array of elevation points, check the box under
Type of Data in file, “Points are NOT in a regular array”. When this box is
checked, the dialog box changes as displayed below:
The ASCII file of points must contain a separate line for each point. Each point or
line must have the values of X, Y, and Z in that order.
OrthoMapper needs to know if the Z’s are in feet and if the X,Y coordinates are
in feet. Be sure to properly indicate this information by checking the appropriate
boxes.
You can indicate that there is header information in the file by indicating the
number of lines to skip before the lines of data.
The Cell Size will be the resolution of the DEM created. You should enter in the
resolution of the orthophoto you will be creating unless the area has very little
relief. A small cell size will allow you to create the very best orthophoto from the
terrain data. The DEM will be approximately 4 times the size of an orthophoto of
corresponding area.
You must fill in numbers for Minimum Z and Maximum Z. These values will act
as filters and not consider any points that are outside the range of values you enter.
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When you are finished entering the information, press the OK button and the DEM will
be created by first creating a TIN, then interpolating the TIN at the Cell Size resolution.
6.5.4
Create DEM from SDTS File
If you wish to create a DEM that is compatible with OrthoMapper from files created
under the Spatial Data Transfer Standard, click on this option.
Note: If you are attempting to convert a BIL file from the
National Elevation Data set (NED) into a DEM file, you must
use the option explained in section 6.4.1 and 6.4.2.
There are a large number of files with the extension of .ddf required to create a
DEM. The next dialog box displays the typical number of files required. You are
asked to choose any of these files.
After choosing a file and clicking on the Open button, the DEM will be constructed
in memory. Information about the DEM will be displayed on the screen. Be sure to
note the Datum and Reference Projection for the DEM. A typical display is
shown below.
Note: An additional format for DEMs distributed by the USGS can be converted
using the Convert Files Options in the Utilities Menu.
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Press the OK button.
You then must enter a folder name in which to put the DEM. Press the Browse
button and select an existing folder. Press the Next button.
After clicking on the Next button, the dialog box will be changed and you will be
allowed to enter a name for the new DEM. This dialog box is displayed below.
It is important to mosaic adjacent DEMs before using them within OrthoMapper.
See the Mosaic DEMs Option explained below.
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Click on the Finished button and the DEM will be created.
6.5.5
Create a DEM from DXF file
This option is designed to be used to import points and break lines created from an
analytical plotter. The DXF file must be created from the software used on the
analytical plotter. Be sure when you export the DXF file that you ask only for XYZ
points and break lines.
The menu for this option is displayed as:
It is important that you choose a DEM Cell Size that is compatible with the data in
your DXF file. The general rule is that the cell size should be smaller than the
smallest distance between points within the DEM. If the Cell Size is chosen too
large, the details in the DEM will be lost.
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6.5.6
November 2005
Mosaic DEMs
This option will allow you to mosaic a number of smaller DEMs into one larger
DEM. As OrthoMapper allows you to use up to 4 DEMs within a project, this
option should not be normally needed. One of the situations for which you might
use this option is to combine DEMs with differing resolution into one composite
DEM.
It is important to use this option if you are importing DEMs from the
USGS SDTS format. There are gaps between adjacent DEMs. If
these gaps are not interpolated and filled in, there will be
unacceptable spatial errors when you create an orthophoto.
If this option is chosen the following dialog menu appears:
All the entries in this menu must be filled in. The DEMs are checked in order. This
means that at a given spatial location the Base DEM value supersedes the values
from any of the other DEMs. The Minimum and Maximum Values can be used as
filters to eliminate elevation values from any DEM.
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6.5.7 DEM Arithmetic
This option allows the user to change a portion of a DEM if there are problems
within the DEM. The user is allowed to add/subtract or multiply the elevations
within a DEM by a user supplied value. These changes can be applied to any
rectangular area within the DEM. This option can also be used to eliminate any bad
or missing sections within the DEM by interpolating from surrounding data.
Sections up to 15 pixels across can be interpolated.
After entering a file name the following dialog box will appear.
The user is expected to enter the number used to modify the DEM into the Values
edit box. If you wish to add this number to the DEM elevations, click on the first
radio button. If you wish to multiply the elevations by this number, click on the
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second radio button. If you wish to convert the elevations from values you believe
are feet into meters, click on the check box “Change Z’s from feet to meters”.
If you wish to interpolate bad values within the DEM, click on the Interpolation
Option check box.
In all cases, the area within the DEM that will be changed is designated within the
Area box.
An example of this process may make it more understandable.
Below is a DEM with a number of problem areas.
The right portion of the DEM appears to have elevations that have units of feet and
the left portion of the DEM has elevations with units of meters.
To correct this, the file name should be entered at this menu, and then the “Change
Z’s from feet to meters” box should be checked.
It was determined that all elevations with an X coordinate greater or equal to
405720 should be changed. On the next page is the dialog box with the option and
coordinates to accomplish this task.
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The resulting DEM is displayed below.
Note the white line at the bottom middle of the image.
It was determined that the data near X = 405690 is either missing or not consistent
with the surrounding data and needs to be interpolated.
The DEM Arithmetic option is again started, and the interpolation option is chosen.
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Note that Xmin and Xmax are below and above the coordinate 405690.
Below is the finished interpolated DEM. Although not perfect, it will be good
enough with which to construct an orthophoto.
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6.6
November 2005
ORTHOPHOTO MOSAIC FUNCTIONS
Within this option, there are 4 functions:
1.
Update an Orthophoto
2.
Manually Create an Orthophoto Mosaic
3.
Automatically Create Orthophoto Mosaic
4.
MergeFill NoData
Each of these is explained below.
6.7.1
Update an Orthophoto
The Update Orthophoto routine is one of the most powerful features of
OrthoMapper. This option allows you to update a portion of an existing
orthophoto with all or a portion of a recent aerial image or another individual
orthophoto. In areas of rapid development this might be the most cost-effective
method of keeping an orthophoto base current. It is also a very good method of
correcting a mosaic for seam line errors and problems with illumination in water.
When you choose this option, a dialog box is displayed which asks you to enter a
base orthophoto and an orthophoto that will be used to update the base orthophoto.
Before choosing this option, you must first make the orthophoto that you will be
using to update the base orthophoto (see first 4 chapters of this manual).
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The top check box allows you to display seam lines generated by the Automatic
Mosaic routine (discussed in the next section).
The seven steps involved in updating an orthophoto mosaic are:
1.
Enter the name for the Base Ortho. The Base Ortho Name is the orthophoto
you wish to update. This can be an existing older orthophoto or a new
orthophoto created using the Automatic Mosaic routine.
2.
Enter the Merge Ortho Name. The Merge Ortho Name is the name of the new
orthophoto that you will be using to update the base orthophoto.
After entering the Merge Ortho Name, the dialog box will appear as below:
3.
Click on the “Create” button to the right of the Merge Area Mask. This
allows you to designate the polygon for the area you wish to merge from the
Merge Orthophoto.
4.
After you have created the Area Mask, you need to decide how you would
like OrthoMapper to match the tone or color between the new and older
orthophoto.
After you click on the Create button to the right of the Merge Area Mask
label, you will be designating a polygon on the Merge Orthophoto (the
orthophoto that is being used to update the older orthophoto).
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The Merge Orthophoto will be displayed and you are expected to designate
the polygon by clicking with the Left Mouse Button. The program will draw
a red line between the locations where you clicked the mouse button. When
you are finished, click the Ctrl/Right Mouse Button and the program will
close the polygon.
If you wish to delete the last point you have just entered, press the Right
Mouse Button.
Base Orthophoto
Merge Orthophoto
The appearance of the Base and Merge Orthophoto after designating the Merge
Area Mask.
5.
6.
Choosing the Color Balance option. The three choices are:
a.
Use the area around the seam to determine the color match. This is the
best overall choice in most situations.
b.
Do not do any color or tone match. In this case OrthoMapper will use
the original values from the new orthophoto in the updated orthophoto.
c.
Use the Merge Area Mask for the Color Match. In this case
OrthoMapper will use the same area on both orthophotos to do the
tone or color match. If the areas have significantly changed, this is not
likely to result in a good color match.
Choosing the Feathering Option:
You can choose to feather the merge image into the base image. Feathering
allows a smooth transition between the images.
If you press the Feathering button OrthoMapper will create a number of
buffers on each side of the seam line. Within each of the buffers, a mixture of
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the two images will be put into the final composite orthophoto. The transition
between the images will be smoother with a larger number of buffers. The
distance between buffers can also be set, in terms of pixels. After clicking on
the Feathering button, the menu will change indicating that you want to
feather the seam.
The default setting of 1 buffer of 10 pixels will give reasonable results in most
conditions. Below are pictures illustrating the buffering process. In this case
the color balance between the two images was much different so that the
buffers would be visible. If the colors between the two images are very close,
the buffers will not be visible.
Pictures illustrating the feathering process. Note the blending of the image
on the right, the result of feathering.
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November 2005
Pressing the Create Mosaic button will create the updated orthophoto.
After updating the Base Orthophoto, the
updated file will now include the area
within the merge area mask from the
Merge Orthophoto.
Correcting an Orthophoto Mosaic for Poor Choice of Seam Lines
The Update Orthophoto routine can be used in conjunction with the Automatic Mosaic
routine to create a corrected orthophoto mosaic. During the Automatic Mosaic routine,
the seam line between individual orthophotos is chosen as a straight line equidistant from
the centers of the individual orthophotos. Many times, especially in urban areas, the
seam line will be in the middle of a structure or other feature above the ground. In these
cases, the structure or building will be leaning in differing directions on either side of the
seam line in the mosaic. To correct this problem, the Update Orthophoto routine can be
used. Below is an example of correcting an orthophoto mosaic created using the
Automatic Mosaic routine of two individual orthophotos.
Below are pictures of two individual orthophotos.
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The mosaic created in the Automatic Mosaic routine is displayed below:
After starting the Update Orthophoto routine, and checking on the Display Seam Line
check box at the top of the menu, the following image is displayed on the left of the
screen. Note the seam line displayed in the image.
While zooming in on the image along the seam line, it is apparent that the seam line has
cut a number of buildings and they appear to be leaning towards the center of the seam
line as displayed below.
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To correct this problem, one must choose one of the individual orthophotos that was used
to create the mosaic.
1. Click on the Browse button to the right of Merge Ortho Name edit box and select
the individual orthophoto.
2. Click on the “Create” button to the right of the Merge Area Mask label.
Look around the image until you find the building that you are going to correct.
Below is an image of the building described above on the individual orthophoto.
Note that the building appears whole.
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3. Outline the area of the building as described at the beginning of this section,
being careful not to cross any other structure.
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4.
After Pressing Ctrl/Right Mouse Button, the polygon above will be defined. To
create the corrected mosaic, just click on the “Create Mosaic” button at the bottom of the
menu. Below is a picture of the corrected mosaic.
It is recommended that all areas on the mosaic be designated before
pressing the “Create Mosaic” button.
To designate another area on the same merge orthophoto, just press the
“Create” button again to create another Merge Area.
To designate an area on a different merge orthophoto, first press the
“Browse” button to select another individual orthophoto, and then the
“Create” button to designate another Merge Area.
Below is the appearance of the base orthophoto in this example after all the areas that
need correction have been designated.
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There is no need to create all of the polygons that need to be updated at one time. You
can click on the button “Exit/Save Polygons” and the polygons you have created up to
that time will be saved. The next time you choose the Update Ortho routine, the existing
polygons will be displayed on the base orthophoto and you can continue to select
additional polygons.
Correcting Illumination Problems within Water
Many times there are illumination problems within water bodies within a mosaic. This
may occur due to a hot spot (reflection of the sun) or problems due to the location of the
seam line within the water.
The easiest method of correcting this problem is to find an individual orthophoto with the
water appearing as you wish and use this routine to update the mosaic. You will be
updating the mosaic with the portion of the individual orthophoto that appears correct.
Another method to correct water problems is to use the Exclusion Polygons you created
to assist in the color balance during the automatic mosaic procedure. This method is
described below.
After entering the Base Ortho Name at the Merge Menu, the dialog box appears as
below:
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Note the third edit box indicating Polygon Files.
This edit box will accept only polygons created as Exclusion Polygons at the menu:
Utilities -> Orthophoto Mosaic Functions -> Create Exclusion Polygon
After entering a Polygon File name, the polygon will be displayed on the Base Ortho as a
green line as depicted below:
The Exclusion Polygon file contains the file name from which the polygon was created.
It is suggested that Feather Seams be turned ON so that there is blending of the updated
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portion of the Merge Orthophoto. After clicking on the Create Mosaic button, the Base
Ortho will be updated using the Exclusion Polygon.
Before update procedure
6.6.2
After update procedure
Manually Create an Orthophoto Mosaic
There will be times you wish to create an orthophoto mosaic but do not wish to use
the automatic mosaicing feature in OrthoMapper. This may occur for large-scale
urban environments. If the automatic mosaic is chosen over a city, it is very likely
that the buildings that fall on a seam will not have the proper perspective. In these
cases, you must manually decide how to seam the individual orthophotos.
The 3 steps you will use to manually create an orthophoto mosaic are as follows.
Steps A and C are further explained below.
A. Create single orthophotos of each image you wish to include in the orthophoto
mosaic.
B. Choose the Manually Create an Orthophoto Mosaic option from the Utilities
Menu.
C. Follow the directions on the screen and below to create the mosaic.
A. Create single orthophotos of each image.
1. Click on the ORTHO button on the main window of OrthoMapper.
2. Choose a project file for one of the images you wish to include in the mosaic
(6_4.PJ for the dialog box displayed below). All of the images you wish to use
in the mosaic must already be oriented (both interior and exterior orientation).
Below is a picture of the top of the Image/DEM Selection dialog box which is
displayed next.
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3. Change the number at the top of the dialog box to the number of images that
will be in the mosaic.
4. Use the Add Image button to add the remaining images to the list.
5. Click on the button “Produce Single Orthophotos from List”.
6. If you entered Tie points in the individual image projects, you can perform a
Block Adjustment (Aerial Triangulation). This will make it much more likely
that the individual orthophotos will be integrated in a seamless fashion. If you
wish to perform a Block Adjustment, click on the button entitled: “Orient block
using auto strip formation”.
7. Enter the name of the DEM file(s) using the Add button that you will be using
to create the mosaic. These are the DEMs you used to orient the individual
images.
An example of how the Image/DEM Selection dialog box can appear for a block of
4 images can be found below.
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8. Press the Next button.
9. Respond to the messages from the Block Adjustment (see section 4.1 on page
32 for a description of these messages).
10. At the next dialog box, just set the Orthophoto Pixel Size and press the Create
Ortho button.
Orthophotos will then be created for each of the images in your list. The names of
the orthophotos will be the image name with an “_ORTHO.TIF” appended. Note
that the orthophotos produced by OrthoMapper are GeoTif files with an
accompanying World file.
B. After the orthophotos are created for each of the images of interest, go to the
Utilities Menu and choose Manually Create an Orthophoto Mosaic option.
C. After choosing this option, the dialog box below will be displayed, as well as a
message box on the upper right of the screen.
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1. First choose the file name for the mosaic or composite orthophoto. You must
use the Browse button to choose the name. If the file does not already exist, go
into the directory you wish to create the mosaic and choose any file name – then
change it to the name you wish before you press the “Save” button.
2. If the file exists, you will be given a chance to delete it or add more orthophotos
to the existing mosaic.
3. If the mosaic file does not exist, the first image you enter will become the
current mosaic and additional images will be added to this image. Below is an
example of the dialog box after entering a mosaic name that does not already
exist. After choosing the mosaic name the dialog box will appear as below.
Note that the messages in the Message Box on the lower right of the screen will
help guide you through these procedures.
4. Next, choose the orthophotos to be included in the mosaic. Again as before,
you must use the Browse button to choose the orthophoto files. You can choose
as many images at one time by selecting them using the Ctrl/Left Button.
5. The dialog box will change after adding images to allow you start creating the
mosaic.
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Choose the mage to be added to the mosaic either from the drop down menu
or by clicking on the index image you wish to add on the left of the screen.
Then press the Add button.
After choosing a file, the program will appear to pause as the file you have
chosen is copied. A message will appear in the Message Box asking you to wait
as the file is copied. You can proceed to the next step when the file name you
entered appears in the “Images within the orthophoto mosaic” list. Below is a
display of a portion of the dialog box after entering the first orthophoto.
6. After the first file has been copied, you can enter the next orthophoto you wish
to add to the mosaic. This orthophoto must have some overlap with the first
photo you have entered. Choose a file name from the “List of orthophotos to be
added the mosaic” drop down menu. Press the Add button.
The dialog box will appear as on the top of the next page.
7. You must next create the Merge Area Mask. Click on the Create button to the
right of “Merge Area Mask” title. You will be choosing the area from the file
listed in the “Next Ortho Name” edit box (the Merge Image) that you wish to
add to the current composite orthophoto (in this case, the first orthophoto you
entered).
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The image you are merging will be displayed on the screen. You are expected
to use the Left Mouse button to define a polygon that will be the area on the
merge orthophoto, which will be added to the current mosaic to make the
composite.
a. Click Left Mouse button to add a vertex to the polygon.
b. Click on the Right Mouse Button to erase the last vertex added.
c. While holding down the Ctrl key, click on the Right Mouse button to
finish defining the polygon. After clicking the Ctrl/Right Mouse button
the polygon will be closed and you will be asked if the polygon displayed
(in red) is to be saved. Click on the Yes button. If you answer No, you
must start over at step 6 and redefine the polygon.
An example of a polygon displayed on the Merge Image and the question displayed
when the polygon has been finished can be found below. Note, that the polygon
will be displayed as a red line, not as the white line in the picture below.
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It is usually best to choose polygon lines along edges of roads within the image.
You can zoom in on the image to more carefully choose the vertices of the polygon.
To Zoom in – while holding down the Alt key, press the Left Mouse button –
OR – roll the mouse wheel forward .
To Zoom out – while holding down the Alt key, press the Right Mouse button
– OR – roll the mouse wheel backward.
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After defining the Merge Area Mask, the dialog box will appear as below.
There are a number of different options that you should consider this point.
a.
8.
Do not allow OrthoMapper to do a color match. This may be appropriate
for images within a strip.
b. Use the area around the seam to determine the color balance. This is the
recommended option.
c. Use the entire image to determine the color balance. This is most
appropriate when the images are fairly homogenous.
d. Choose the area in the overlap region on each image to determine the
color balance. This is the most flexible option. In urban areas, it is
recommended that you choose the roadways as the color match areas.
e. You can choose to Feather the seam between existing mosaic and the
merge image. This is the recommended procedure except in very complex
urban areas.
If you choose to manually choose the color match area, you must create a
Color Match Mask. This will allow you to match the tones and colors between
the image you are merging and the current composite orthophoto. If you are
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adding an image within the same flight strip, you may not need to perform a
color match. If this is the case, just press the Add Image to Mosaic button on
the bottom of the dialog box and the merge image will be added to the current
composite orthophoto.
It is suggested that you all OrthoMapper do the color balance and correction.
USE THE DEFAULT SETTING FOR COLOR MATCHING. If you wish
to create the Color Match Mask, you must:
a. Uncheck the box entitled “Do not color match Merge Ortho with Composite
Ortho
b. Click on the Create button to the right of the “Color Match Mask” title.
The process is exactly like creating a Merge Area Mask. In this case you
will be indicating a common area between the Merge Image and the current
composite image that will be used to match the colors and tones.
c. If for some reason, the color band order is different between the Merge
Image and the current composite orthophoto, you can change the Merge
Band Order at this time.
The Feathering Option is described on page 88.
When all of the information above has been entered in the dialog box, just press the
Add Image to Mosaic button at the bottom of the box.
Steps 4 through 7 can be repeated for all of the additional orthophotos you wish to add
to the mosaic.
When you are finished adding orthophotos to the mosaic, press the Finished button
at the bottom of the dialog box.
6.7.3
Automatically Create an Orthophoto Mosaic
This option allows you to create a mosaic from a number of individual orthophotos.
This option does not allow you to choose where the orthophotos are joined. If you
wish to create an orthophoto mosaic of large-scale urban areas, it is recommended
that you use the “Manually Create an Orthophoto Mosaic” option instead of this
option.
Be sure to correct the image for Lens Falloff/Sun angle before you make any
orthophotos if you did not choose to do this when the orthophotos were created. If
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you do not, the color balance will likely be poor. See Automatic Mosaic and Color
Balance Example in Appendix A.
When this option is chosen the Automatic Mosaic Dialog Menu is displayed:
At the menu that is displayed, click on the Add Images or Read List button
Read List will add an ordered list of images to be included in the mosaic. The list
must be a text file with each image on a single line. Full path for each image must
be entered.
Add Images will allow you to interactively select the images to be included in the
mosaic. Click on the Select Button and select the orthophotos you wish to include
in the mosaic. A file is selected by clicking with the Ctrl/Left Button . Any
number of existing orthophotos may be selected.
After selecting the orthophotos to be included in the mosaic, the following dialog
box will appear.
It is important to keep adjacent images in order because the overlap area is used to
calculate the color balance. You should thus change the insert order for creating the
orthophoto by selecting an image name then clicking on the Change Order button.
The most efficient method of creating an orthophoto mosaic is to order the images
across the strips. For example if you have 3 strips, the image should be ordered as:
1-1, 2-1,3-1, 1-2, 2-2, 3-2, etc. Where the first number of each pair is the strip
number, and the second number is the photo number.
If the images are not in the proper order, set the “Ortho Color Balance Order”.
1. Choose the image from the “Selected Orthophotos” drop down menu you
would like to use as the standard color for the whole mosaic.
2. Then enter 1 in the edit box to the right of the “Ortho Color Balance Order”
title.
3. Click on the Change Order button.
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Subset the orthophotos to eliminate unwanted portions.
Press the SubSet Images button. The Subset Orthophoto Menu will then be
displayed. See section 6.10.3 for a description of the operation of the sub-set option
Automatic Mosaic Dialog Menu
You must next enter the name for the mosaic. You MUST press the Browse button
to choose the directory, and then either choose an existing file (which then will be
overwritten) or type in a name of your choice. The file name cannot contain any
spaces and the file name must end in .TIF . For example you might want to name
the mosaic MOSAIC.TIF.
You can choose any cell size for the mosaic. The default cell size is the cell size for
the existing orthophotos.
The default Starting X and Starting Y is the Northern most and Eastern most
coordinate for the orthophotos you are mosaicing.
A minimum value of 0.74 should be entered in the Image Size edit box if you do
not subset the images to eliminate the black border around the image. This will
assure that no black space is included in your mosaic.
If you have a 3 band black and white image with colored lines drawn on the image,
you can force OrthoMapper include the colored lines in the overlap area. This
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option allows you to designate (draw) resource boundaries directly on stereo pairs
of panchromatic paper print. The “Add Color Overlays in overlap areas” checkbox
will only be visible if you are using this type of image. In this case, check the box
within the Transparency Option section.
The two options available when you choose color balancing are: (1) Feathering and
(2) Radiometric Normalization. Feathering has been explained previously.
Radiometric Normalization forces the mosaic to be “on the average”
radiometrically flat and will attempt to take out any trends in the brightness. This is
especially important for large mosaics. For small mosaics, this option can be turned
off.
You can choose either Bi-Linear or Bi-Cubic resampling to create the mosaic. BiCubic resampling will allow you to create a sharper mosaic. Bi-Linear resampling
will tend to correct for image noise.
You may set the “Exclude Values” in the Color Balance box, but it not
recommended. The easiest way to do this is to click on the “Display Histograms”
button and examine the histograms displayed.
Above is an example of the histograms displayed for two images that contain a
number of lakes. The minimum color values should be set to a number just larger
than the first peak in each band. The default numbers displayed are set to eliminate
the lowest 10% of the pixels and seem to work well in most cases.
After changing any of the default options, press the “OK” button and the
orthophoto mosaic will be created.
Automatic Color Balance
The automatic color balance feature within OrthoMapper is one of the best in the
industry. In order for the color balance algorithm to work optimally, one can
correct each image for Lens Falloff/Uneven Illumination (see page 76), but is not
necessary. Even if one does not correct for the illumination, the algorithm will
produce an orthophoto with very even color (or panchromatic) tones. On the next
page are screen captures from a 1.5 Gigabyte mosaic produced from 21 individual
aerial images. The image on the left was produced using NO color corrections.
The image on the right was produced using the Automatic Color Balance algorithm,
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but without using the correction for uneven illumination. To appreciate the color
balance, you should view the next page within the Ortho_Manual.PDF file on the
OrthoMapper Install Disk.
Orthophoto produced using the
Automatic Color Balance feature
within the Automatic Mosaic routine.
Orthophoto produced using NO color
balance options. This is unlikely to be
an acceptable product.
Exclusion Polygons
If you defined any exclusion polygons, you can enter their names before starting the
Automatic Mosaic. Exclusion polygons are polygons you wish to exclude from the
calculation of the color balance. It is usually a good idea to exclude water bodies from
the color balance as will cause uneven shading on the final product. This is especially
true of water with sun glint. The Exclusion Polygons are defined on an Orthophoto
Mosaic Function entry.
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One-Bit Overlays
If 1-bit overlays are used in the Automatic Mosaic routine, the following defaults
will be displayed.
The Transparence Value sets the value to be used as the background value (in this
case there are black lines). The check box, “Use all data in overlap area” lines from
either image in the overlay area will be included in the mosaic. If this box is
unchecked, only lines that appear in the first image to be added will be included in
the mosaic.
6.6.4
MergeFill NoData
This option is designed to fill in the gaps on either side of an orthophoto that has
been transformed into a different coordinate system. The data from adjacent
orthophotos is used to fill in the gaps.
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The menu that appears when this option is chosen is:
This option will only work with TIF files. When entering the Merge Orthophoto
names use the Ctrl/Left Button to choose each of the merge orthophotos that are
necessary.
An example of a base orthophoto and the resultant orthophoto in which the gaps
have been filled can be found below.
Base Ortho
Resultant Ortho
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6.7
CHANGE COLOR/CONTRAST IN AN IMAGE
6.7.1
Interactive Color Balance
There will be times that one would want to change the color or contrast in an
orthophoto created in OrthoMapper. This is especially important for color images.
If you choose this option from the Utilities Menu, the following dialog box will be
displayed.
There are three options at this menu.
1. Fixed Linear Stretch – This option will allow you to change an images file
values such that 98%of the data is linearly stretched over the range 0 to 255 in
each color band.
2. Interactive Linear Stretch – This option will allow you to determine the range
over which to stretch the image values. After pressing the Stretch button, you
will view the image selected and then can adjust the stretch until the image
looks as you wish.
3. Interactive Gamma Correction – This option will allow you to determine a
gamma correction to the image. A Gamma Correction is a non-linear stretch. A
low value of gamma will emphasize the low values in the image, and a high
value of gamma will emphasize the high values in the image. After pressing the
Stretch button, you will view the image selected and then can adjust the stretch
until the image looks as you wish.
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6.7.2
November 2005
Correct Lens Falloff /Uneven Illumination
In general images have uneven illumination due to a number of factors. The two
largest effects can be attributed to the optical properties of the lens and the bidirectional scattering from the sun illumination. Due to physical optical
considerations, the light falling on the film is always brighter at the center of the
image. The scattering of the sun illumination is always brighter in a direction away
from the sun. This option attempts to correct both of these problems. The process
will only work for images that have been oriented.
The following Radiometric Image Menu will appear:
Press the Browse button. The standard Windows Browse Dialog box will appear
and you should choose the project in which the images that you wish to correct.
The Windows Browse Dialog box will look like the following:
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After selecting the project, the Radiometric Image Menu will change and appear as
below:
If there are images in the project that you do not want to correct, they can be
removed from the list by selecting the image and pressing the Remove Image from
List button.
Press the OK key.
OrthoMapper will then proceed to correct all of the images in the project that were
not removed.
The names of the original images will be changed to include the name BAK within
the name. A number of progress bars will be displayed on the screen during the
radiometric correction process.
6.7.3
Log and Exponential Transformation
This option is designed to transform images with poor contrast
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The user is expected to browse for the images to be transformed.
Original Image
Log Transformation
Exponential Transformation
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6.7.4
November 2005
Color Balance and Color Blend a Block of Images
The Color Balancing function is designed to match the average color and radiometrically
normalize a number of aerial images or orthophotos that do not overlap. Color Blending
is designed to match the color between adjacent orthophoto tiles that are within 20 pixels
of adjacent tiles. Color Blending only affects the edges of the adjacent tiles.
Color Balancing
The Color Balance option is chosen from the Main Menu of OrthoMapper. Choose the
Utilities Menu -> Correct Image Color/Contrast -> Color Balance a Block of Images.
Choosing this function is illustrated below.
The following menu will appear when the option is selected.
Color Balance Menu
1)
The images that you wish to color balance can be selected by two different
methods. The Browse button can be used to select image file names using the
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normal Windows method. The Ctrl/Right Button can be used to select multiple
image file names.
The Add List button allows one to select all file names in a list of file names.
The list must be a text file with one file name per line. The file name must
include the whole path name for the file. An example of such a list can be found
below
M:\original\4800-30.tif
M:\original\4800-46.tif
M:\original\4800-60.tif
2)
The image on which you wish to standardize the colors must be entered using the
next Browse button. The image can be one of the images that were selected in
step 1 above, or an image not in the list but that has been previously Color
Balanced.
3)
Next you should choose a minimum value in each of the bands below which the
algorithm will not use to calculate the mean and variance for each individual
image. This value is included to designate a number that will eliminate low
values in the scene, usually water pixels, from the calculation.
4)
The color balance algorithm will force each of the chosen images to have the
same average brightness. You can either use the average brightness of the
“Standardized” image or you may choose a number between 100 and 160. The
default method is to use the average brightness of the standardized image. If you
wish to choose a different number, click on the second radio button and enter a
number in the edit box to the right of the button.
5)
The color balance algorithm will force each of the chosen images to have the
same variance – that of the standardized image. This is the default operation of
the algorithm. If you do not want to standardize the variance for the images, you
can “uncheck” the Minimize Radiometric Variance check box. This is not
recommended.
6)
The default operation of the color balance algorithm is to save the original image
file as a backup file. If you do not wish to save the original files, you must
“check” the Do NOT save original images as backup files box.
7)
You can choose to normalize the image you have chosen as the “Standardized”
image. If this image has already been normalized previously, you do not need to
do this. The check box: Include standardized image in normalization
process will allow you to select this option.
8)
Finally, if you have selected orthophoto tiles in step 1 and they are within 20
pixels of each other, you can choose to Color Blend the tiles at the edges. Click
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on the Color Blend check box. This option is explained below in the next
section. There will be additional choices at the lower right of the menu for the
Color Blend option as depicted below.
Color Balance Menu
9)
Click on the OK button to initiate the process.
When the Color Balancing Menu disappears, the process is finished.
6.7.5
Color Blending
The Color Blending option will blend the color between adjacent orthophoto tiles. This
option will only work if the edges of the tiles are within 20 pixels of each other. This
option will work best when there is little or no space between the tiles.
The Color Blending option is chosen from the Utilities Menu as depicted below:
The Color Blend function can also be chosen from the Color Balance Menu.
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If the option is chosen from the Utilities Menu, the following menu is displayed:
Color Blend Menu
The user is expected to select the following for Color Blending:
1)
The images that you wish to color blend can be selected by two different methods.
The Browse button can be used to select image file names using the normal
Windows method. The Ctrl/Right Button can be used to select multiple image
file names.
The Add List button allows one to select all file names in a list of file names.
The list must be a text file with one file name per line. The file name must
include the whole path name for the file. An example of such a list can be found
below
M:\original\4800-30.tif
M:\original\4800-46.tif
M:\original\4800-60.tif
If the Color Blend option was chosen at the Color Balance Menu, then the images
chosen at that menu will be Color Blended after they have been previously Color
Balanced.
2)
The window size to be used to determine the color at any point on the edge can be
selected. The default is 55, which will correspond to an area of 55 x 55 pixels.
3)
The Buf Size value is the buffer size in pixels around the edges of the orthophoto
tile. The Color Blending will affect the pixels within this buffer. The default
value is 400.
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4)
North-South edges and/or East-West edges can be chosen for color blending.
Normally, the color is very consistent along a strip, but differs between strips.
You must choose one or both pairs of edges.
5)
You can choose to create index images of the corrected images. These are 1/10
resolution versions of the corrected images. The file names for the index images
are the original image name with the text “_INX” inserted within the name. For
example, if the original image name was 405_350.TIF, the index image will be
named 405_350_INX.TIF. You can use these images to create a mosaic of the
corrected images to verify that the color balance algorithm has accomplished the
task correctly.
6)
Click on the OK button to initiate the process.
When the process is complete, the Color Blending menu will disappear.
Creating an Index Image
To create a mosaic of the index images that have been created from the Color Blending
process, you should do the following:
1.
2.
3.
4.
5.
6.
7.
8.
From the Main Menu of OrthoMapper, choose the Utilities menu.
Choose Orthophoto Mosaic Functions at the drop down menu.
Choose Automatically Create Orthophoto Mosaic from the menu
displayed.
At the Automatic Mosaic menu, choose all of the index images created during the
Color Blending process.
Enter a name for the mosaic of the index images.
Click on the radio button Do NOT color/tone balance the mosaic.
Be sure that the Feather Seams box toward the bottom of the menu is NOT
checked.
Click the OK button.
On the next page is an example of Color Balancing and Color Blending as applied to nine
orthophoto tiles.
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A mosaic of the
original nine
orthophoto tiles .
A mosaic of the
index images
created during the
Color Blending
process of the nine
orthophoto tiles.
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6.8
November 2005
IMPORT EXTERIOR ORIENTATION PARAMETERS
This option is for the users who would like to use OrthoMapper only for making
the orthophotos and some other programs to accomplish the photo exterior
orientation. See the discussion in Appendix F -- “Format for Exterior
Orientation Parameters” to construct the files to be imported into this option.
The procedure for using this option is as follows:
1.
2.
3.
Start individual projects for each image in your project. Choosing the “Use
only ground control coordinates … ” at the Welcome menu (see section 2.3).
Perform the interior orientation for each image.
Choose this option
The following dialog box will be displayed:
1) Option 1 – Import Exterior Orientation Parameters in individual photo
projects.
2) Option 2 – Create a new multiple photo project by importing Exterior
Orientation Parameters.
3) Option 3 – Import EO Parameters into an existing multiple photo project.
After the one of these options is chosen, the dialog box changes to allow you to
designate the images to be included in the project.
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You must first enter the number of Images you wish in the project. Then “Add a
Image/Project” button must be chosen for each of the images you wish to add.
Note: when you add an Image, OrthoMapper must be able to find the
corresponding project file. If the project file cannot be located, you will be asked to
Browse and select the project. After OrthoMapper has located the project file,
the image name will appear in the list box.
When you are finished adding projects, press the “Continue” button. The next
dialog box allows you to enter the Exterior Orientation Parameters.
There are 4 steps to filling in this dialog box.
1.
2.
3.
Check the appropriate boxes at the top of the dialog box. OrthoMapper
needs to know the units for the values you will be importing.
Browse for the file with the exterior orientation parameters you wish to
import. The format for this file is explained in Appendix F. In general, the
file will contain the camera orientation parameters for each image, which have
been exported from an aerial triangulation (AT) program.
Enter a name for the composite project you are creating. OrthoMapper will
automatically append the .PJ to the name you enter.
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November 2005
Associate each of the images in the project with the Exterior Orientation
Parameters in the file you have imported. This procedure is explained below.
After importing the Exterior Orientation Parameters file, the following dialog box will be
displayed.
To Associate the EO parameters with an image:
1.
2.
3.
4.
5.
Choose the Strip number and Photo number from the drop down menu on the
right side of the dialog box for the photo displayed on the left.
Press the “Associate” button.
The Image name on the left. will be automatically incremented when you
press the Associate button.
If you make a mistake, press the “Reset Association” button and start over.
When you are finished, press the OK button.
To use the project to create an orthophoto:
1.
2.
3.
4.
6.9
Open the project as an existing project.
Click on the large ORTHO button at the main menu.
Enter the name of the DEM
Press the “Next” button and follow the directions in section 4.0.
ROTATE IMAGE/DEM
This option allows you to rotate an image in 90 degrees increments and rotate the
data in a project by the same amount.
After choosing Rotate, you will be given a choice of Rotate an Image, or Rotate a
Project. In both cases, the following dialog box is displayed:
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The rotated image or project will be created in the same directory as the original
image or project.
6.10 TRIM/SUBSET/RESIZE AN IMAGE/DEM
6.10.1
Trim/Subset an Image or DEM
This option can create subsets and resolution averages of a number of different
types of files. The files that the subset can create are:
a. Unrectified digital images with a .LAN or .TIF extension.
b. DEM files with a .DEM extension.
c. Orthophoto images with .TIF or .LAN extension.
The user is expected to enter an input file. The output file name will default to the
input name followed by “_SUB”. If needed, you must change the “Use one band”
option at this time. When both names have been entered, the menu changes to
allow you enter the coordinates for the subset or trim lines.
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The user can create a sub image using the row and column coordinates or the
ground coordinates. In addition, the user can enter a different Output Resolution.
This latter option will average the pixels in an n by n square to produce an output
pixel, where n is the number entered in the Resolution box – for example, if a 2 is
entered, the program will average a 2 by 2 square of pixels and output one pixel.
Trim to a polygon by indicating a visual subset
There are two options to trim an image/orthophoto to an irregular polygon. The
user can indicate the bounds for the subset by clicking on the check box “Use the
input image to indicate a visual subset”. This option will allow the user to use the
left mouse button to determine a polygon, which will be used to subset the image.
Polygon drawn on the image to indicate subset area.
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The image constructed from the polygon above.
Trim to a polygon file
This option allows the user to trim an orthophoto to a polygon contained in a file.
The types of files that are supported are:
1. A text file containing the X,Y or column,row coordinates of the vertices of
the polygon.
2. An ArcView shape file containing X,Y coordinates of a polygon.
3. An AutoCad DXF file containing X,Y coordinates of a polygon.
Press the Browse button within the “Coordinate File” area. At this point the
standard browse window appears and allows you to choose file names with one of
the required extensions:
The user is expected to enter file names with an extension of .SHP, .DXF, or .TXT.
The program should then trim the orthophoto to the coordinate file polygon, filling
in all areas outside the polygon with zeros. Be sure that the radio buttons are
properly selected before you proceed. The default value for the units’ button will
match the orthophoto.
If more than one file is chosen, the name in the output file box will change to a
Base File Name. The actual output file name will be a combination of this name
and the coordinate file name.
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Trim to rectangle
The last option on the subset menu allows the user to strip pixels along the
boundary of an image to create a rectangular image without zero pixels along the
boundary. This can be useful for images projected from one coordinate system to
another. If the user checks the box entitled “Create largest subset with no border
pixels,” an image will be created with the largest bounding box entirely within the
input image. Click the OK button to create the subset image.
6.10.2
Batch Trim
This option allows you to Trim or Subset a number of images at the same time.
Two operations are allowed at this menu: (1) Create images with no border pixels,
and (2) Trim a number of images using different coordinate files for each image.
In both cases, the user is expected to enter the files to be trimmed using the Browse
button. As in previous menus, multiple files can be chosen using the Ctrl key in
conjunction with the Left Mouse Button.
After choosing the image files, one can choose to create the largest subset with no
border pixels or choose coordinate files to trim each image.
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By clicking on the “Trim the input images using the coordinate files below” button,
the bottom half of the menu becomes visible. You are expected to click on the
“Associate” button and choose coordinate files for each image file.
To review the names of the coordinate files associated with each image file, select
the image file within the combo box at the top of the menu.
After finishing all your choices, press the OK button to create the trimmed images.
6.10.3
Trim Orthophotos before Mosaicing
Below the Subset Orthophoto Menu, a picture of the file with the name in the
Orthophoto Image edit box is displayed. An orange rectangle is drawn on top of the
image. The area within the orange rectangle will be included in the subset image.
The user is expected to change the location of the lines to indicate which part of this
image is to be included in the mosaic.
It is important to eliminate all portions of the image that should not be included in
the final mosaic. One does not want any of the black area outside the image to be
included. In addition, the writing on the sides of the image or the fiducial marks
should not be included.
By clicking on the SubSet All button, all of the images will be trimmed without
examining all of the individual images. This option should only be used if you
choose to trim all of the images with the same polygon.
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Figure 7, orthophoto of an image showing the original orange boundary.
The user is expected to drag each of the 4 corners of the orange rectangle to an
appropriate place. A corner is dragged by positioning the mouse cursor near the corner
and holding the Left Mouse button down, then moving the corner to the desired
location.
A reasonable place to move the corners is illustrated below.
Figure 8, orthophoto with new orange boundary displayed.
The Subset Ortho button should then be clicked. Repeat process for each
additional image in your data set. When the last image has been processed, you
will be returned to the Automatic Mosaic Dialog Menu displayed on the next page.
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6.10.4 Create Orthophoto Tiles
This option allows the user to create orthophoto tiles from an existing mosaic or
from individual orthophotos of images.
6.10.4.1 Create Tiles from a mosaic
After choosing the orthophoto mosaic the following dialog menu will be displayed.
The user is expected to enter the size of the tiles in both the X direction and the Y
direction. The user can choose to have any % overlap between the tiles.
After entering the X-Size, Y-Size and overlap, click on the Calculate Tiles button
then click on the OK button.
6.10.4.2 Create Tiles from orthophotos
This option allows the user to create tiles from individual orthophotos. After
entering the file names for a block of orthophotos, the following dialog menu will
be displayed.
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The X-Size and Y-Size is set for a block of images that was acquired with a 30%
side lap. If the block was acquired with a 40% side lap, the values for X-Size and
Y-Size should be reduced by about 10%.
It is suggested that each of the orthophotos should be trimmed using the “Trim
Orthophotos before Mosaicing” option previously discussed (Section 6.10.3).
After setting the X-Size and Y-Size, click on the OK button and the tiles should be
created.
6.10.5
Resize Image or DEM
This option allows the user to create reduced resolution images or DEMs.
Multiple reduced resolution images or DEMs can be created at the same time from
this menu. Choose all of the images for which reduced resolution copies are to be
created, using the “Browse” button. Enter the New Resolution value in the edit
box. Press the “OK” button to create the new images.
6.11
BUNDLE ADJUSTMENT
This option will allow the user to run a bundle adjustment on an existing project.
The project must first be created at the “ORTHO” option.
Other options at this menu will allow you to run the Edit Points and the Densify
Points algorithm.
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6.12
November 2005
CREATE FLICKER IMAGES
This option allows the user to create flicker images for quality control of an
orthophoto production process. This option is designed for use with the visual
orientation method of orienting images. The option will create images that can be
used in the Flicker/Split Window option (on the Image Display menu choice).
The two flicker images will be created from the orthophoto created by
OrthoMapper
and a composite flicker image created from all of the reference orthophotos in the
associated project.
1. The user is expected to enter the names for a number of orthphotos using the top
Browse button.
2. Choose a project file associated with the orthophoto name displayed in the
combo box.
3. Then click on the button “Add Files to List”.
4. After adding all the images/projects, browse for the Output Flicker Path – this
will be the directory in which the flicker images will be created.
The process (2 and 3) is repeated until all the orthophotos chosen in step one are in
the list. Press the “Create Flicker Images” to create the flicker images. The flicker
images will be in the directory in which the orthophotos have been created.
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6.13
November 2005
STRETCH AN IMAGE TO MAP
There may be times you wish to transform an image that is not geo-referenced into
the coordinate system of another image which has been geo-referenced (an
orthophoto), a raster map file, or shape files. This option can also be used to force
two orthophotos into exactly the same coordinate system.
This option supports both an Affine and a second order polygon transformation.
The user is expected to enter the file name for the Map file and up to 3 file names for
shape files. The shape files will be displayed as an overlay to the map file. The
Raster File is the image you wish to transform into the coordinate system of the Map
file(s). The output file is the name you wish for the transformed file – this must be a
.TIF file.
If you only have shape files, the routine will create a blank raster image the size of
the output image that you must specify. If only shape files are entered, the following
dialog box is displayed.
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You are expected to enter the upper left corner of the output-transformed image. This
template will be used to display the shape files, so the coordinates you enter must
encompass the coordinates of the shape files entered. The cell size will be the output
cell size for the transformed image. The Number of Columns and Number of Rows
will determine the size of the output image.
After the parameters have been entered, the user is expected to find 4 or more
corresponding points between the map files and the raster image (7 or more for a
second order transformation). The interface is similar to that of the visual orientation
menu. The corresponding points are chosen on the full resolution images displayed at
the bottom of the screen.
You are expected to right click on the low-resolution images at the top of the screen
and then find the corresponding point in the full resolution image at the bottom of the
screen. Then press the “Measure Point” button on the dialog menu. When you are
finished finding points, press the “Finished” button and the output image will be
created.
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6.14
November 2005
MEASURE POINT FUNCTION
This function allows one to quality control the orthophotos created. The user must
have a text file of points or real ground control must have been used to create the
orthophoto.
To arrive at a realistic estimate of the errors in an orthophoto, the user must measure
the positions on an orthophoto for which the coordinates are known. The Measure
Point Function (MPF) allows one to do this task. The MPF displays a window
around a coordinate for the orthophoto under test. The user then clicks on the correct
position of the point. The MPF records the difference between the known coordinate
and the coordinate of the point at which the user clicked. These differences and their
standard deviations are stored in a file for the user to characterize the errors in the
orthophoto.
To start the MPF, go to the Utilities Menu and click on the “Measure Point” entry.
After clicking on the “Measure Point” entry, the Measure Point menu is displayed.
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1)
2)
3)
November 2005
You are expected to enter a name for the file with the known coordinates. The file
must contain lines with three numbers on each line – control point ID, X and Y.
Alternately, you can browse for the GPT files used to create the orthophoto. This
only makes sense if the orthophoto was created using real ground control points.
Next click on the Browse button on the next line to enter the name for the output
file. This will be the file in which the measurements for this function will be stored.
Give the file a name with an extension of .TXT
Next click on the Browse button to select the orthophoto mosaic you have created.
After you have entered the file name for the mosaic, you will see a menu that looks
similar to the one depicted below:
In this case there are 13 points in the file CP_CONTROL_SP.TXT – note the number 13
displayed below the Image Name edit box.
The mosaic you created should be displayed on the left of the screen. You are now
expected to:
1)
2)
3)
Click on the button Go To Point
On the orthophoto display at the left, position the cursor on the correct position for
the point, then press the S key. You can reposition the measured point as often as
you wish – it will not be recorded until you press the Go To Point button to display
the next point.
You will need to repeat these last two steps for each of the points in the file.
Below is an example of the display for a control point in a file.
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The green box surrounds the area in which the control point is located.
The orange cross is the position on the image where you believe is the correct location
for this point. The orange cross will be displayed after you press the S key.
To facilitate measuring the correct position of a point, the orientation of red crosshairs
can be changed. To change the orientation for either of the red lines:
1)
2)
3)
4)
Locate a feature along which you wish one of the red lines to be parallel.
While holding down the Ctrl key, press the Left Mouse button.
Move the cursor along the feature.
While holding down the Ctrl key, press the Left Mouse button again.
The red line should now line up with the feature. Both red lines can be changed
independently.
To return the red lines back to the default horizontal and vertical orientations:
While holding down the Ctrl key, press the Right Mouse button.
On the next page is an example of red cross hairs aligned along the intersecting roads.
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After measuring the last point in the Coordinate File, the MPF function will end. You
should use the Notepad program to examine the text file created by the function.
6.15
SPECIALIZED TRANSFORMATIONS
A number of transformations that are used by a small number of users are grouped
under this menu item.
The transformations that are currently implemented are:
Extend DEM
Reorder Bands
Extract one Band
Create a Tilted Image
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6.15.1
November 2005
Extend DEM
This option allows the user to extend a DEM from a shoreline into the water. This
can be useful for attempting to determine shoreline erosion from orthophotos created
from aerial imagery at two different dates.
6.15.2
Reorder Bands
If you wish to permanently change the order of the bands in a multi-band (color)
image, this option can be chosen. The Change Display Option will change the order
of bands for display purposes only.
The first menu that appears asks you to choose the image.
After Browsing for the input file, press the “Choose Bands” button. The following
menu will appear:
You are then expected to:
1. Set the Input Image band number.
2. Then change the Output Image band number for each Input Image band number.
Press the OK button when you are finished.
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6.15.3
November 2005
Extract One Band
This option will allow one to create a one band LAN from a multi-band LAN file.
The dialog box which is displayed when this option is chosen is as displayed below:
You are expected to enter an input file name, an output file name, and the band you
wish copied to the output file. Press the OK button when all the required information
has been entered.
6.15.4
Create a Tilted Image
This option will create an unrectified image from an orthophoto that has the same
orientation as the unrectified image in the project. Creating a tilted image can be
useful when comparing land use changes over time on unrectified images.
If the project image has been oriented and an orthophoto was chosen during
orientation, the following dialog box is displayed:
You cannot change the name of the Template – this is the name of the image in the
project.
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The radiometric values for the new unrectified image will come from the file whose
name is entered in the OrthoPhoto File Name edit box.
The elevation values used to construct the unrectified image will come from the file
whose name is entered in the DEM File Name edit box.
The newly created unrectified image will be stored in a file with the name stored in
the New Unrectified Name edit box.
Press the OK Button. The new unrectified image will be produced and stored in the
Area Directory.
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OrthoMapper Order Form
Send to: Image Processing Software, Inc.
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Phone: (608) 233-5033
Fax:
(608) 238-7086
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Thank you for your order.
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