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Baumer VisiLine IP
User's Guide for Gigabit Ethernet Cameras
Document Version: v1.5
Release: 15.09.2014
Document Number: 11110804
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Table of Contents
8.3.4 Advanced Timings for GigE Vision ® Message Channel .................................. 22
9.1.4 PRNU / DSNU Correction (FPN - Fixed Pattern Noise) ................................. 29
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4
9.7.2 Baumer Optronic Sequencer in Camera xml-file ............................................ 47
9.7.4 Capability Characteristics of Baumer-GAPI Sequencer Module .................... 48
10.3 Packet Size and Maximum Transmission Unit (MTU) ......................................... 52
10.4.1 Example 1: Multi Camera Operation – Minimal IPG ..................................... 53
10.4.2 Example 2: Multi Camera Operation – Optimal IPG ..................................... 53
10.7.2 DHCP (Dynamic Host Configuration Protocol) ............................................. 58
10.8.3 Fault 2: Lost Packet at the End of the Data Stream ..................................... 60
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1. General Information
Thanks for purchasing a camera of the Baumer family. This User´s Guide describes how to connect, set up and use the camera.
Read this manual carefully and observe the notes and safety instructions!
Target group for this User´s Guide
This User's Guide is aimed at experienced users, which want to integrate camera(s) into a vision system.
Copyright
Any duplication or reprinting of this documentation, in whole or in part, and the reproduction of the illustrations even in modified form is permitted only with the written approval of
Baumer. This document is subject to change without notice.
Classification of the safety instructions
In the User´s Guide, the safety instructions are classified as follows:
Notice
Gives helpful notes on operation or other general recommendations.
Pictogram
Caution
Indicates a possibly dangerous situation. If the situation is not avoided, slight or minor injury could result or the device may be damaged.
2. General safety instructions
Caution
Heat can damage the camera. Provide adequate dissipation of heat, to ensure that the temperatures does not exceed the value (see Heat Transmission).
As there are numerous possibilities for installation, Baumer does not specify a specific method for proper heat dissipation.
3. Intended Use
The camera is used to capture images that can be transferred over a GigE interface to a
PC.
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4. General Description
1 2 3
No. Description
1 Tube
2 C-Mount lens connection
3 LED´s
5 4
No. Description
4 Power supply / Digital-IO
5 Data- / PoE-Interface
All Baumer Gigabit Ethernet cameras of the VisiLine IP family are characterized by:
Best image quality
Flexible image acquisition
Fast image transfer
Perfect integration
Compact design
Reliable operation
▪
▪
▪ Low noise and structure-free image information
High quality mode with minimum noise
Industrially compliant process interface with parameter setting capability (trigger and flash)
▪
▪
▪
▪
Reliable transmission up to 1000 Mbit/sec according to IEEE802.3
Cable length up to 100 m
PoE (Power over Ethernet)
Baumer driver for high data volume with low CPU load
▪ High-speed multi-camera operation
▪ Gen<I>Cam™ and GigE Vision ® compliant
▪
▪
▪
Flexible generic programming interface ( Baumer-
GAPI) for all Baumer cameras
Powerful Software Development Kit (SDK) with sample codes and help files for simple integration
▪ Baumer viewer for all camera functions
▪ Gen<I>Cam™ compliant XML file to describe the camera functions
Supplied with installation program with automatic camera recognition for simple commissioning
▪
▪
▪
▪
▪
Protection class IP 65/67
Light weight flexible assembly
State-of-the-art camera electronics and precision mechanics
Low power consumption and minimal heat generation
5. Camera Models
Camera Type
Sensor
Size
CCD Sensor (monochrome / color)
VLG-02M.I / VLG-02C.I
VLG-12M.I / VLG-12C.I
VLG-20M.I / VLG-20C.I
CMOS Sensor (monochrome / color)
VLG-22M.I / VLG-22C.I
VLG-40M.I / VLG-40C.I
1/4"
1/3"
1/1.8"
2/3"
1"
Dimensions
Resolution
656 x 490
1288 x 960
1624 x 1228
2044 x 1084
2044 x 2044
4 - M3 depth 5
Full
Frames
[max. fps]
160
42
27
55
29
8,3 41,5 3,1
ø 49,5
46
12,9 20,2 12,9
45,8
8,3
52,9 12,9
8 - M3 depth 5
◄ Figure 1
Dimensions of a
Baumer VisiLine IP camera
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10
Figure 2 ►
Temperature measuring point
6. Installation
Lens mounting
Notice
Avoid contamination of the sensor and the lens by dust and airborne particles when mounting the support or the lens to the device!
Therefore the following points are very important:
▪
▪
▪
▪ Install the camera in an environment that is as dust free as possible!
Keep the dust cover (bag) on camera as long as possible!
Hold the print with the sensor downwards with unprotected sensor.
Avoid contact with any optical surface of the camera!
6.1 Environmental Requirements
Storage temperature
Operating temperature*
Temperature
-10°C ... +70°C ( +14°F ... +158°F) see Heat Transmission
* If the environmental temperature exceeds the values listed in the table below, the camera must be cooled. (see Heat Transmission)
Humidity
Storage and Operating Humidity 10% ... 90%
Non-condensing
6.2 Heat Transmission
Caution
Heat can damage the camera. Provide adequate dissipation of heat, to ensure that the temperature does not exceed 50°C (122°F).
As there are numerous possibilities for installation, Baumer does not specify a specific method for proper heat dissipation.
T
Measure Point
T
Maximal Temperature
50°C (122°F)
6.3 Mechanical Tests
Environmental Testing
Vibration, sinusodial
Standard
IEC 60068-2-6
Vibration, broad band
Shock
Bump
IEC 60068-
2-64
IEC 60068-
2-27
IEC60068-2-
29
Parameter
Search for Resonance
Amplitude underneath crossover frequencies
Acceleration
Test duration
Frequency range
Acceleration
Displacement
Test duration
Puls time
Acceleration
Pulse Time
Acceleration
10-2000 Hz
1.5 mm
10 g
150 min
20-1000 Hz
10 g
5.7 mm
300 min
11 ms / 6 ms
50 g
2 ms
100 g
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Figure 3 ►
LED positions on Baumer VisiLine cameras.
7. Pin-Assignment
7.1 Power Supply and Digital IOs
Power supply / Digital-IO
(SACC-CI-M12MS-8CON-SH TOR 32)
/wire colors of the connecting cable)
4
3
2
8
5 6
7
1
1
2
3
4
5
6
OUT 3 white
Power Vcc+ brown
IN 1 green yellow IO GND
U ext
OUT
OUT 1 grey pink
7
8
Power GND blue
OUT 2 red
Notice
The electrical data are available in the respective data sheet.
7.2 Ethernet Interface (PoE)
Notice
The VisiLine IP supports PoE (Power over Ethernet) IEEE 802.3af Clause 33, 48V
Power supply.
3
4
5
6
1
2
7
8
Ethernet
(SACC-CI-M12FS-8CON-L180-10G)
(wire colors of the connecting cable / Phoenix cable, other cable may differ)
5
6
4
3
7
8
2
1
D1+
D1-
D2+
D2-
D4+
D4-
D3-
D3+ white / orange orange white/green green white/brown brown white/blue blue
7.2.1 LED Signaling
1
2
LED
1
2
Signal green green flash yellow
Meaning
Link active
Receiving
Transmitting
8. Product Specifications
8.1 Spectral Sensitivity
The spectral sensitivity characteristics of monochrome and color matrix sensors for Visi-
Line IP cameras are displayed in the following graphs. The characteristic curves for the sensors do not take the characteristics of lenses and light sources without filters into consideration.
Values relating to the respective technical data sheets of the sensors.
1 0
0 8
0 6
0 4
0 2
0
400
VLG-02M.I
500 600 700 800
Wave Length [nm]
900 1000
1 0
0 8
0 6
0 4
0 2
0
400
VLG-02C.I
450 500 550
Wave Length [nm]
600 650 700
◄ Figure 4
Spectral sensitivities for
Baumer cameras with
0.3 MP CCD sensor.
1 0
0 8
0 6
0 4
0 2
0
400
VLG-12M.I
500 600 700 800
Wave Length [nm]
900 1000
1 0
0 8
0 6
0 4
0 2
0
400
VLG-12C.I
450 500 550 600
Wave Length [nm]
650 700
◄ Figure 5
Spectral sensitivities for
Baumer cameras with
1,2 MP CCD sensor.
1 0
0 8
0 6
0 4
0 2
0
400
VLG-20M.I
500 600 700 800
Wave Length [nm]
900 1000
1 0
0 8
0 6
0 4
0 2
0
400
VLG-20C.I
450 500 550 600
Wave Length [nm]
650 700
◄ Figure 6
Spectral sensitivities for
Baumer cameras with
2.0 MP CCD sensor.
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Figure 7 ►
Spectral sensitivities for Baumer cameras with 5.0, 4,0 MP CMOS sensor.
350 450 550
VLG-22M.I / VLG-40M.I
650 750 850 950 1050
Wave Length [nm]
350 450 550
VLG-22C.I / VLG-40C.I
650 750 850 950 1050
Wave Length [nm]
8.2 Field of View Position
The typical accuracy by assumption of the root mean square value is displayed in the figure and the table below:
±XR
± α
0,5
±XM photosensitive surface of the sensor cover glas thickness: D front cover glass thickness: 1 ± 0.1 mm
7,2
15,6
60,2 gure 8 ►
of the
P
14,6
A
± Z optical path c-mount (17.526 mm)
Camera
Type
± X
M
[mm]
± Y
M
[mm]
± X
R
[mm]
± Y
R
[mm]
± z
Zyp
[mm]
± α
[°] typ
A
[mm]
D**
[mm]
VLG.I-02* 0.09
VLG.I-12* 0.06
VLG.I-20* 0.06
VLG.I-22* 0.07
VLG.I-40* 0.07
0.09
0.06
0.06
0,07
0,07
0.09
0.06
0.06
0.07
0.07
0.09
0.06
0.06
0.07
0.07
0.025
0.025
0.025
0.025
0.025
0.7
0.7
0.7
0,5
0,5
16.1
16.6
0.75
0.5
16.6
0.5
16.2
0.55 ± 0.05
16.2
0.55 ± 0.05
typical accuracy by assumption of the root mean square value
* C or M
** Dimension D in this table is from manufacturer datasheet (edition 06/2012)
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8.3
Acquisition Modes and Timings
The image acquisition consists of two separate, successively processed components.
Exposing the pixels on the photosensitive surface of the sensor is only the first part of the image acquisition. After completion of the first step, the pixels are read out.
Thereby the exposure time (t exposure ed for the readout (t readout
) can be adjusted by the user, however, the time need-
) is given by the particular sensor and image format.
Baumer cameras can be operated with three modes, the Free Running Mode, the Fixed-
Frame-Rate Mode and the Trigger Mode.
The cameras can be operated non-overlapped *) or overlapped. Depending on the mode used, and the combination of exposure and readout time:
Non-overlapped Operation
Here the time intervals are long enough to process exposure and readout successively.
Overlapped Operation
In this operation the exposure of a frame
(n+1) takes place during the readout of frame (n).
Exposure Exposure
Readout Readout
8.3.1 Free Running Mode t
In the "Free Running" mode the camera records images permanently and sends them to the PC. In order to achieve an optimal result (with regard to the adjusted exposure time exposure
and image format) the camera is operated overlapped.
In case of exposure times equal to / less than the readout time (t frame rate of the camera is reduced.
exposure
≤ t readout
), the maximum frame rate is provided for the image format used. For longer exposure times the
Timings:
A - exposure time frame (n) effective
B - image parameters frame (n) effective
C - exposure time frame (n+1) effective
D - image parameters frame (n+1) effective
Exposure
Readout
Image parameters:
Offset
Gain
Mode
Partial Scan
Flash t flash
= t exposure t exposure(n) t flash(n) t flashdelay t exposure(n+1) t readout(n) t flash(n+1) t readout(n+1)
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*) Non-overlapped means the same as sequential.
8.3.2 Fixed-Frame-Rate Mode
With this feature Baumer introduces a clever technique to the VisiLine IP camera series, that enables the user to predefine a desired frame rate in continous mode.
For the employment of this mode the cameras are equipped with an internal clock generator that creates trigger pulses.
Notice
From a certain frame rate, skipping internal triggers is unavoidable. In general, this depends on the combination of adjusted frame rate, exposure and readout times.
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8.3.3 Trigger Mode
After a specified external event (trigger) has occurred, image acquisition is started. Depending on the interval of triggers used, the camera operates non-overlapped or overlapped in this mode.
With regard to timings in the trigger mode, the following basic formulas need to be taken into consideration:
Case t exposure
< t readout t exposure
> t readout
(1)
(2)
(3)
(4)
Formula t t t t earliestpossibletrigger(n+1) notready(n+1)
= t earliestpossibletrigger(n+1) notready(n+1)
= t
= t
= t exposure(n) readout(n)
- t exposure(n)
+ t readout(n) exposure(n) exposure(n+1)
- t exposure(n+1)
8.3.3.1 Overlapped Operation: t exposure(n+2) = t exposure(n+1)
In overlapped operation attention should be paid to the time interval where the camera is unable to process occuring trigger signals (t exposures. When this process time t external events again.
notready notready
). This interval is situated between two
has elapsed, the camera is able to react to
After t notready age (t readout(n)
has elapsed, the timing of (E) depends on the readout time of the current im-
) and exposure time of the next image (t exposure(n+1)
). It can be determined by the formulas mentioned above (no. 1 or 3, as is the case).
In case of identical exposure times, t notready tion.
remains the same from acquisition to acquisi-
Trigger
Timings:
A - exposure time frame (n) effective
B - image parameters frame (n) effective
C - exposure time frame (n+1) effective
D - image parameters frame (n+1) effective
E - earliest possible trigger
Exposure
Readout
TriggerReady
Image parameters:
Offset
Gain
Mode
Partial Scan
Flash t min t triggerdelay t exposure(n) t notready t flash(n) t flashdelay t exposure(n+1) t readout(n) t flash(n+1) t readout(n+1)
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8.3.3.2 Overlapped Operation: t exposure(n+2) > t exposure(n+1)
If the exposure time (t tion, the time the camera is unable to process occurring trigger signals (t down.
exposure
) is increased from the current acquisition to the next acquisinotready
) is scaled
This can be simulated with the formulas mentioned above (no. 2 or 4, as is the case).
Trigger
Exposure
Readout
TriggerReady
Flash t min t triggerdelay t exposure(n) t notready t flash(n) t flashdelay t exposure(n+1) t readout(n) t flash(n+1) t exposure(n+2) t readout(n+1)
Timings:
A - exposure time frame (n) effective
B - image parameters frame (n) effective
C - exposure time frame (n+1) effective
D - image parameters frame (n+1) effective
E - earliest possible trigger
Image parameters:
Offset
Gain
Mode
Partial Scan
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8.3.3.3 Overlapped Operation: t exposure(n+2) < t exposure(n+1)
If the exposure time (t tion, the time the camera is unable to process occurring trigger signals (t up.
exposure
) is decreased from the current acquisition to the next acquisinotready
) is scaled
When decreasing the t exposure
such, that t notready age will not start (the trigger will be skipped).
exceeds the pause between two incoming trigger signals, the camera is unable to process this trigger and the acquisition of the im-
Trigger t min t triggerdelay t exposure(n)
Timings:
A - exposure time frame (n) effective
B - image parameters frame (n) effective
C - exposure time frame (n+1) effective
D - image parameters frame (n+1) effective
E - earliest possible trigger
F - frame not started / trigger skipped
Image parameters:
Offset
Gain
Mode
Partial Scan
Exposure
Readout
TriggerReady
Flash t notready t exposure(n+1) t readout(n) t readout(n+1) t exposure(n+2 t flash(n) t flashdelay t flash(n+1)
Notice
From a certain frequency of the trigger signal, skipping triggers is unavoidable. In general, this frequency depends on the combination of exposure and readout times.
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8.3.3.4 Non-overlapped Operation
If the frequency of the trigger signal is selected for long enough, so that the image acquisitions (t exposure
+ t readout
) run successively, the camera operates non-overlapped.
Trigger
Exposure
Readout
TriggerReady
Flash t min t triggerdelay t exposure(n) t notready t flash(n) t flashdelay t readout(n) t exposure(n+1) t flash(n+1) t readout(n+1)
Timings:
A - exposure time frame (n) effective
B - image parameters frame (n) effective
C - exposure time frame (n+1) effective
D - image parameters frame (n+1) effective
E - earliest possible trigger
Image parameters:
Offset
Gain
Mode
Partial Scan
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8.3.4 Advanced Timings for GigE Vision ® Message Channel
The following charts show some timings for the event signaling by the asynchronous message channel. Vendor-specific events like "TriggerReady", "TriggerSkipped", "TriggerOverlapped" and "ReadoutActive" are explained.
8.3.4.1 TriggerReady
This event signals whether the camera is able to process incoming trigger signals or not.
Trigger t exposure(n) t exposure(n+1)
Exposure
t readout(n) t readout(n+1)
Readout t notready
TriggerReady
8.3.4.2 TriggerSkipped
If the camera is unable to process incoming trigger signals, which means the camera should be triggered within the interval t notready
, these triggers are skipped. On Baumer Visi-
Line IP cameras the user will be informed about this fact by means of the event "Trigger-
Skipped".
Trigger t exposure(n) t exposure(n+1)
Exposure
t readout(n) t readout(n+1)
Readout t notready
TriggerReady
TriggerSkipped
8.3.4.3 TriggerOverlapped
This signal is active, as long as the sensor is exposed and read out at the same time. which means the camera is operated overlapped.
Trigger t exposure(n) t exposure(n+1)
Exposure
t readout(n) t readout(n+1)
Readout
Trigger
Overlapped
Once a valid trigger signal occures not within a readout, the "TriggerOverlapped" signal changes to state low.
8.3.4.4 ReadoutActive
While the sensor is read out, the camera signals this by means of "ReadoutActive".
Trigger t exposure(n) t exposure(n+1)
Exposure
t readout(n) t readout(n+1)
Readout
Readout
Active
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8.4
Software
8.4.1 Baumer GAPI
Baumer GAPI stands for Baumer Generic Application Programming Interface. With this
API Baumer provides an interface for optimal integration and control of Baumer cameras.
This software interface allows changing to other camera models.
It provides interfaces to several programming languages, such as C, C++ and the .NET™
Framework on Windows ® , as well as Mono on Linux ® operating systems, which offers the use of other languages, such as e.g. C# or VB.NET.
8.4.2 3 rd Party Software
Strict compliance with the Gen<I>Cam™ standard allows Baumer to offer the use of 3 rd
Party Software for operation with cameras of the VisiLine IP family.
You can find a current listing of 3 rd Party Software, which was tested successfully in combination with Baumer cameras, at http://www.baumer.com/de-en/products/identificationimage-processing/software-and-starter-kits/third-party-software/
9. Camera Functionalities
9.1 Image Acquisition
9.1.1 Image Format
A digital camera usually delivers image data in at least one format - the native resolution of the sensor. Baumer cameras are able to provide several image formats (depending on the type of camera).
Compared with standard cameras, the image format on Baumer cameras not only includes resolution, but a set of predefined parameter.
These parameters are:
▪ Resolution (horizontal and vertical dimensions in pixels)
▪ Binning Mode
Camera Type
Monochrome
VLG-02M.I
VLG-12M.I
VLG-20M.I
VLG-22M.I
VLG-40M.I
Color
VLG-02C.I
VLG-12C.I
VLG-20C.I
VLG-22C.I
VLG-40C.I
■
■
■
■
■
■
■
■
■
■
■
■
■
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□
■
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■
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■
■
■
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■
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■
■
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9.1.2 Pixel Format
On Baumer digital cameras the pixel format depends on the selected image format.
9.1.2.1 Definitions
RAW: Raw data format. Here the data are stored without processing.
Bayer: Raw data format of color sensors.
Color filters are placed on these sensors in a checkerboard pattern, generally in a 50% green, 25% red and 25% blue array.
Figure 9 ►
Sensor with Bayer
Pattern
Mono: Monochrome. The color range of mono images consists of shades of a single color. In general, shades of gray or black-and-white are synonyms for monochrome.
RGB: Color model, in which all detectable colors are defined by three coordinates,
Red, Green and Blue.
Red
White
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Figure 10 ►
RBG color space displayed as color tube.
Black
Green
Blue
The three coordinates are displayed within the buffer in the order R, G, B.
BGR: Here the color alignment mirrors RGB.
YUV: Color model, which is used in the PAL TV standard and in image compression.
In YUV, a high bandwidth luminance signal (Y: luma information) is transmitted together with two color difference signals with low bandwidth (U and V: chroma information). Thereby U represents the difference between blue and luminance
(U = B - Y), V is the difference between red and luminance (V = R - Y). The third color, green, does not need to be transmitted, its value can be calculated from the other three values.
YUV 4:4:4 Here each of the three components has the same sample rate.
Therefore there is no subsampling here.
YUV 4:2:2 The chroma components are sampled at half the sample rate.
This reduces the necessary bandwidth to two-thirds (in relation to
4:4:4) and causes no, or low visual differences.
YUV 4:1:1 Here the chroma components are sampled at a quarter of the sample rate.This decreases the necessary bandwith by half (in relation to 4:4:4).
ure 12 ► o 12
.
Pixel depth: In general, pixel depth defines the number of possible different values for each color channel. Mostly this will be 8 bit, which means 2 8 different "colors".
For RGB or BGR these 8 bits per channel equal 24 bits overall.
Two bytes are needed for transmitting more than 8 bits per pixel - even if the second byte is not completely filled with data. In order to save bandwidth, the packed formats were introduced to Baumer VisiLine IP cameras. In this formats, the unused bits of one pixel are filled with data from the next pixel.
8 bit:
12 bit:
Byte 1 Byte 2 unused bits
Byte 3
◄ Figure 11
Bit string of Mono 8 bit and RGB 8 bit.
Packed:
Byte 1
Pixel 0
Byte 2
Pixel 1
Byte 1 Byte 2 Byte 3
◄ Figure 13
Spreading of two pixels in
Mono 12 bit over three bytes
(packed mode).
9.1.2.2 Pixel Formats on Baumer VisiLine IP Cameras
Camera Type
Monochrome
VLG-02M.I
VLG-12M.I
VLG-20M.I
VLG-22M.I
VLG-40M.I
Color
VLG-02C.I
VLG-12C.I
VLG-20C.I
VLG-22C.I
VLG-40C.I
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□
□
□
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9.1.3 Exposure Time
On exposure of the sensor, the inclination of photons produces a charge separation on the semiconductors of the pixels. This results in a voltage difference, which is used for signal extraction.
Light
Photon
Charge Carrier
Figure 14 ►
Incidence of light causes charge separation on the semiconductors of the sensor.
Pixel
The signal strength is influenced by the incoming amount of photons. It can be increased by increasing the exposure time (t exposure
).
On Baumer VisiLine IP cameras, the exposure time can be set within the following ranges
(step size 1μsec):
Camera Type
Monochrome
VLG-02M.I
VLG-12M.I
VLG-20M.I
VLG-22M.I
VLG-40M.I
Color
VLG-02C.I
VLG-12C.I
VLG-20C.I
VLG-22C.I
VLG-40C.I
t exposure
min
4 μsec
4 μsec
4 μsec
15 μsec
20 μsec
4 μsec
4 μsec
4 μsec
15 μsec
20 μsec t exposure
max
60 sec
60 sec
60 sec
1 sec
1 sec
60 sec
60 sec
60 sec
1 sec
1 sec
9.1.4 PRNU / DSNU Correction (FPN - Fixed Pattern Noise)
Camera Type
CCD
VLG-02M.I / VLG-02C.I
VLG-12M.I / VLG-12C.I
VLG-20M.I / VLG-20C.I
CMOS
VLG-22M.I / VLG-22C.I
VLG-40M.I / VLG-40C.I
□
□
□
■
■
CMOS sensors exhibit nonuniformities that are often called fixed pattern noise (FPN).
However it is no noise but a fixed variation from pixel to pixel that can be corrected. The advantage of using this correction is a more homogeneous picture which may simplify the image analysis. Variations from pixel to pixel of the dark signal are called dark signal nonuniformity (DSNU) whereas photo response nonuniformity (PRNU) describes variations of the sensitivity. DNSU is corrected via an offset while PRNU is corrected by a factor.
The correction is based on columns. It is important that the correction values are computed for the used sensor readout configuration. During camera production this is derived for the factory defaults. If other settings are used (e.g. different number of readout channels) using this correction with the default data set may degrade the image quality. In this case the user may derive a specific data set for the used setup.
PRNU / DSNU Correction Off PRNU / DSNU Correction On
29
30
9.1.5 HDR (High Dynamic Range)
Camera Type
CCD
VLG-02M.I / VLG-02C.I
VLG-12M.I / VLG-12C.I
VLG-20M.I / VLG-20C.I
CMOS
VLG-22M.I / VLG-22C.I
VLG-40M.I / VLG-40C.I
□
□
□
■
■
Beside the standard linear response the sensor supports a special high dynamic range mode (HDR) called piecewise linear response. With this mode illuminated pixels that reach a certain programmable voltage level will be clipped. Darker pixels that do not reach this threshold remain unchanged. The clipping can be adjusted two times within a single exposure by configuring the respective time slices and clipping voltage levels. See the figure below for details.
In this mode, the values for t
Expo0
, t
Expo1
, Pot
0 and Pot
1 can be edited.
t
The value for t
Expo2
Expo1
)
will be calculated automatically in the camera. (t
Expo2
= t exposure
- t
Expo0
-
HDR Off HDR On
High
Illumination
Low Illuminati on t
Expo0 t exposure t
Expo1 t
Expo2
Pot2
Pot1
Pot0
9.1.6 Look-Up-Table
The Look-Up-Table (LUT) is employed on Baumer VisiLine IP monochrome and color cameras. It contains 2 12 (4096) values for the available levels. These values can be adjusted by the user.
9.1.7 Gamma Correction
With this feature, Baumer VisiLine IP cameras offer the possibility of compensating nonlinearity in the perception of light by the human eye.
For this correction, the corrected pixel intensity (Y') is calculated from the original intensity of the sensor's pixel (Y original
) and correction factor γ using the following formula (in oversimplified version):
H
Y' = Y γ original
On Baumer VisiLine IP cameras the correction factor γ is adjustable from 0.001 to 2.
The values of the calculated intensities are entered into the Look-Up-Table (see 9.1.5).
Thereby previously existing values within the LUT will be overwritten.
Notice
If the LUT feature is disabled on the software side, the gamma correction feature is disabled, too.
0
▲ Figure 15
Non-linear perception of the human eye.
H - Perception of bright-
ness
E - Energy of light
E
31
9.1.8 Region of Interest
With the "Region of Interest" (ROI) function it is possible to predefine a so-called Region of Interest (ROI) or Partial Scan. This ROI is an area of pixels of the sensor. On image acquisition, only the information of these pixels is sent to the PC. Therefore, not all lines of the sensor are read out, which decreases the readout time (t frame rate.
readout
). This increases the
This function is employed, when only a region of the field of view is of interest. It is coupled to a reduction in resolution.
The ROI is specified by four values:
▪ Offset X - x-coordinate of the first relevant pixel
▪ Offset Y - y-coordinate of the first relevant pixel
▪ Size X - horizontal size of the ROI
▪ Size Y - vertical size of the ROI
9.1.8.1 ROI
Start ROI
End ROI
Figure 16 ►
ROI: Parameters
ROI Readout
In the illustration below, readout time would be decreased to 40%, compared to a full frame readout.
Readout lines
32
Figure 17 ►
Decrease in readout time by using partial scan.
9.1.9 Binning
On digital cameras, you can find several operations for progressing sensitivity. One of them is the so-called "Binning". Here, the charge carriers of neighboring pixels are aggregated. Thus, the progression is greatly increased by the amount of binned pixels. By using this operation, the progression in sensitivity is coupled to a reduction in resolution.
Baumer cameras support three types of Binning - vertical, horizontal and bidirectional.
In unidirectional binning, vertically or horizontally neighboring pixels are aggregated and reported to the software as one single "superpixel".
In bidirectional binning, a square of neighboring pixels is aggregated.
Binning Illustration Example without ◄ Figure 18
Full frame image, no binning of pixels.
1x2
2x1
2x2
◄ Figure 19
Vertical binning causes a vertically compressed image with doubled brightness.
◄ Figure 20
Horizontal binning causes a horizontally compressed image with doubled brightness.
◄ Figure 21
Bidirectional binning causes both a horizontally and vertically compressed image with quadruple brightness.
33
34
9.1.10 Brightness Correction (Binning Correction)
The aggregation of charge carriers may cause an overload. To prevent this, binning correction was introduced. Here, three binning modes need to be considered separately:
Binninig Realization
1x2 1x2 binning is performed within the sensor, binning correction also takes place here. A possible overload is prevented by halving the exposure time.
2x1
2x2
2x1 binning takes place within the FPGA of the camera. The binning correction is realized by aggregating the charge quantities, and then halving this sum.
2x2 binning is a combination of the above versions.
Total charge quantity of the
4 aggregated pixels
Binning 2x2
Figure 22 ►
Aggregation of charge carriers from four pixels in bidirectional binning.
Charge quantity Super pixel
9.1.11 Flip Image
The Flip Image function let you flip the captured images horizontal and/or vertical before they are transmitted from the camera.
Notice
A defined ROI will also flipped.
Camera Type
VLG-02M.I / VLG-02C.I
VLG-12M.I / VLG-12C.I
VLG-20M.I / VLG-20C.I
VLG-22M.I / VLG-22C.I
VLG-40M.I / VLG-40C.I
Normal
■
■
■
■
■
Flip vertical
□
■
□
□
■
◄ Figure 23
Flip image vertical
Normal Flip horizontal
◄ Figure 24
Flip image horiontal
Normal Flip horizontal and vertical
◄ Figure 25
Flip image horiontal and vertical
35
36
9.2 Color Processing
Baumer color cameras are balanced to a color temperature of 5000 K.
Oversimplified, color processing is realized by 4 modules.
r g b
Camera
Module r' g' b'
Bayer
Processor
Y r'' g'' b''
Color
Transfor mation
RGB
Figure 26 ►
Color processing modules of Baumer color cameras.
White balance
The color signals r (red), g (green) and b (blue) of the sensor are amplified in total and digitized within the camera module.
Within the Bayer processor, the raw signals r', g' and b' are amplified by using of independent factors for each color channel. Then the missing color values are interpolated, which results in new color values (r'', g'', b''). The luminance signal Y is also generated.
The next step is the color transformation. Here the previously generated color signals r'', g'' and b'' are converted to the chroma signals U and V, which conform to the standard.
Afterwards theses signals are transformed into the desired output format. Thereby the following steps are processed simultaneously:
▪
▪ Transformation to color space RGB
▪ External color adjustment
Color or YUV adjustment as physical balance of the spectral sensitivities
▪
▪
▪
In order to reduce the data rate of YUV signals, a subsampling of the chroma signals can be carried out. Here the following items can be customized to the desired output format:
Order of data output
Subsampling of the chroma components to
Limitation of the data rate to 8 bits
YUV 4:2:2 or YUV 4:1:1
9.3 Color Adjustment – White Balance
This feature is available on all color cameras of the Baumer VisiLine IP series and takes place within the Bayer processor.
White balance means independent adjustment of the three color channels, red, green and blue by employing of a correction factor for each channel.
Figure 27 ►
Examples of histogramms for a nonadjusted image and for an image after user- specific white balance..
9.3.1 User-specific Color Adjustment
The user-specific color adjustment in Baumer color cameras facilitates adjustment of the correction factors for each color gain. This way, the user is able to adjust the amplification of each color channel exactly to his needs. The correction factors for the color gains range from 1 to 4.
non-adjusted histogramm histogramm after user-specific color adjustment
9.3.2 One Push White Balance
Here, the three color spectrums are balanced to a single white point. The correction factors of the color gains are determined by the camera (one time).
non-adjusted histogramm histogramm after
„one push“ white balance
◄ Figure 28
Examples of histogramms for a non-adjusted image and for an image after "one push" white balance.
9.4 Analog Controls
9.4.1 Offset / Black Level
On Baumer VisiLine IP cameras, the offset (or black level) is adjustable from 0 to 255 LSB
(relating to 12 bit).
Camera Type Step Size 1 LSB
Relating to
Monochrome
VLG-02M.I / VLG-02C.I
VLG-12M.I / VLG-12C.I
VLG-20M.I / VLG-20C.I
Color
VLG-22M.I / VLG-22C.I
VLG-40M.I / VLG-40C.I
12 bit
12 bit
12 bit
12 bit
12 bit
37
38
9.4.2 Gain
In industrial environments motion blur is unacceptable. Due to this fact exposure times are limited. However, this causes low output signals from the camera and results in dark images. To solve this issue, the signals can be amplified by a user-defined gain factor within the camera. This gain factor is adjustable.
Notice
Increasing the gain factor causes an increase of image noise.
CCD Sensor
Camera Type
Monochrome
VLG-02M.I
VLG-12M.I
VLG-20M.I
Color
VLG-02C.I
VLG-12C.I
VLG-20C.I
CMOS Sensor
Camera Type
Monochrome
VLG-22M.I
VLG-40M.I
Color
VLG-22C.I
VLG-40C.I
Gain factor [db]
0...26
0...26
0...26
0...26
0...26
0...26
Gain factor [db]
0...18
0...18
0...18
0...18
9.5 Pixel Correction
9.5.1 General information
A certain probability for abnormal pixels - the so-called defect pixels - applies to the sensors of all manufacturers. The charge quantity on these pixels is not linear-dependent on the exposure time.
The occurrence of these defect pixels is unavoidable and intrinsic to the manufacturing and aging process of the sensors.
The operation of the camera is not affected by these pixels. They only appear as brighter
(warm pixel) or darker (cold pixel) spot in the recorded image.
Warm Pixel
Charge quantity
„Warm Pixel“
Charge quantity
„Cold Pixel“
Cold Pixel
Charge quantity
„Normal Pixel“
◄ Figure 29
Distinction of "hot" and
"cold" pixels within the recorded image.
◄ Figure 30
Charge quantity of "hot" and "cold" pixels compared with "normal" pixels.
39
9.5.2 Correction Algorithm
On cameras of the Baumer VisiLine IP series, the problem of defect pixels is solved as follows:
▪
▪ Possible defect pixels are identified during the production process of the camera.
The coordinates of these pixels are stored in the factory settings of the camera.
▪ Once the sensor readout is completed, correction takes place:
▪
▪ Before any other processing, the values of the neighboring pixels on the left and the right side of the defect pixels, will be read out. (within the same bayer phase for color)
Then the average value of
▪
▪ these 2 pixels is determined to correct the first defect pixel
Finally, the value of the second defect pixel is is corrected by using the previously corrected pixel and the pixel of the other side of the defect pixel.
The correction is able to correct up to two neighboring defect pixels.
Average Value
Defect Pixels
Corrected Pixels
9.5.3 Defectpixellist
As stated previously, this list is determined within the production process of Baumer cameras and stored in the factory settings.
Additional hot or cold pixels can develop during the lifecycle of a camera. In this case
Baumer offers the possibility of adding their coordinates to the defectpixellist.
The user can determine the coordinates *) of the affected pixels and add them to the list.
Once the defect pixel list is stored in a user set, pixel correction is executed for all coordinates on the defectpixellist.
40
*) Position in relation to Full Frame Format (Raw Data Format / No flipping).
9.6 Process Interface
9.6.1 Digital IOs
9.6.1.1 User Definable Inputs
The wiring of these input connectors is left to the user.
Sole exception is the compliance with predetermined high and low levels (0 .. 4,5V low,
11 .. 30V high).
The defined signals will have no direct effect, but can be analyzed and processed on the software side and used for controlling the camera.
The employment of a so called "IO matrix" offers the possibility of selecting the signal and the state to be processed.
On the software side the input signals are named "Trigger", "Timer" and "LineOut 1..3".
state selection
(inverter) signal selection
(software side)
4
3
2
8
5 6
7
1
(Input) Line 1 state high state low
IO Matrix
Trigger
Timer
LineOut 1
LineOut 2
LineOut 3
◄ Figure 31
IO matrix of the
Baumer VisiLine on input side.
41
42
9.6.1.2 Configurable Outputs
With this feature, Baumer offers the possibility of wiring the output connectors to internal signals, which are controlled on the software side.
Hereby on VisiLine IP cameras, the output connector can be wired to one of provided internal signal: "Off", "ExposureActive", "Line 0", "Timer 1 … 3", "ReadoutActive", "User0
… 2", "TriggerReady", "TriggerOverlapped", "TriggerSkipped", "Sequencer Output 0 ... 2".
Beside this, the output can be disabled.
Figure 32 ►
IO matrix of the
Baumer VisiLine IP on output side.
4
3
2
8
5 6
7
1
(Output) Line 1
(Output) Line 2
(Output) Line 3 state selection
(inverter) state high state low state high state low state high state low
IO Matrix signal selection
(software side)
Off
Line0
TriggerReady
TriggerOverlapped
TriggerSkipped
ExposureActive
ReadoutActive
UserOutput0
UserOutput1
UserOutput2
Timer1Active
Timer2Active
Timer3Active
SequencerOutput0
SequencerOutput1
SequencerOutput2
9.6.2 IO Circuits
Notice
Low Active: At this wiring, only one consumer can be connected. When all Output pins
(1, 2, 3) connected to IO_GND, then current flows through the resistor as soon as one
Output is switched. If only one output connected to IO_GND, then this one is only usable.
The other two outputs are not usable and may not be connected (e.g. IO Power V
CC
)!
Output high active
Camera Customer Device
IO Power VCC
U ext
Pin
IOUT
Out (n)
Pin RL
IO GND
Output low active
Camera Customer Device
IO Power VCC
RL
Out
U ext
Pin (Out1, 2, 3)
IOUT
Out1 or Out2 or Out3
IO GND
IO GND
Input
Customer Device
DRV
IN1 Pin
Camera
IN GND Pin
9.6.3 Trigger
Trigger signals are used to synchronize the camera exposure and a machine cycle or, in case of a software trigger, to take images at predefined time intervals.
U
30V
A
Trigger (valid)
Exposure
11V high
4.5V
0 low t
▲ Figure 33
Trigger signal, valid for
Baumer cameras.
B
Readout
Different trigger sources can be used here.
C
Time
◄ Figure 34
Camera in trigger mode:
A - Trigger delay
B - Exposure time
C - Readout time
9.6.4 Trigger Source og ra mm able logic co ol ntr ph oto
electric sens or so ftwa re trigge r
Har dware
trigger trigge r signal others broadcast
Trigger Delay:
The trigger delay is a flexible user-defined delay between the given trigger impulse and the image capture. The delay time can be set between 0.0 μsec and 2.0 sec with a stepsize of 1 μsec. In the case of multiple triggers during the delay the triggers will be stored and delayed, too.
The buffer is able to store up to 512 trigger signals during the delay.
Your benefits:
▪ No need for a perfect alignment of an external
▪ trigger sensor
Different objects can be captured without hardware changes
Each trigger source has to be activated separately. When the trigger mode is activated, the hardware trigger is activated by default.
◄ Figure 35
Examples of possible trigger sources.
43
9.6.5 Debouncer
The basic idea behind this feature was to seperate interfering signals (short peaks) from valid square wave signals, which can be important in industrial environments. Debouncing means that invalid signals are filtered out, and signals lasting longer than a user-defined testing time t
DebounceHigh
will be recognized, and routed to the camera to induce a trigger.
In order to detect the end of a valid signal and filter out possible jitters within the signal, a second testing time t
If the signal value falls to state low and does not rise within t as end of the signal.
DebounceLow was introduced. This timing is also adjustable by the user.
DebounceLow
, this is recognized
The debouncing times t
DebounceHigh of 1 μsec.
and t
DebounceLow
are adjustable from 0 to 5 msec in steps
Debouncer:
Please note that the edges of valid trigger signals are t shifted by t
DebounceHigh
DebounceLow
!
and
Depending on these two timings, the trigger signal might be temporally stretched or compressed.
U
30V
Incoming signals
(valid and invalid)
11V
4.5V
0 high low t
∆t
1
∆t
2
∆t
3
∆t
4
∆t
5
∆t
6
Debouncer t
DebounceHigh t
DebounceLow t
U
30V
Filtered signal
11V
4.5V
0 high t
∆t x t
DebounceHigh
DebounceLow
high time of the signal
user defined debouncer delay for state high
user defined debouncer delay for state low low t
9.6.6 Flash Signal
This signal is managed by exposure of the sensor.
Furthermore, the falling edge of the flash output signal can be used to trigger a movement of the inspected objects. Due to this fact, the span time used for the sensor readout t can be used optimally in industrial environments. readout
44
9.6.7 Timers
Timers were introduced for advanced control of internal camera signals.
For example the employment of a timer allows you to control the flash signal in that way, that the illumination does not start synchronized to the sensor exposure but a predefined interval earlier.
On Baumer VisiLine IP cameras the timer configuration includes four components:
Trigger t triggerdelay t exposure
Exposure
t
TimerDelay
Timer t
TimerDuration
◄ Figure 37
Poss ble Timer configuration on a Baumer
VisiLine
Component
TimerTriggerSource
Description
This feature provides a source selection for each timer.
TimerTriggerActivation This feature selects that part of the trigger signal (edges or states) that activates the timer.
TimerDelay This feature represents the interval between incoming trigger signal and the start of the timer.
TimerDuration By this feature the activation time of the timer is adjustable.
9.6.7.1 Flash Delay
As previously stated, the Timer feature can be used to start the connected illumination earlier than the sensor exposure.
▪
▪
▪
This implies a timer configuration as follows:
The flash output needs to be wired to the selected internal Timer signal.
Trigger source and trigger activation for the Timer need to be the same as for the sensor exposure.
) needs to be set to a lower value than the trigger
▪
The TimerDelay feature (t
TimerDelay delay (t triggerdelay
The duration (t
).
TimerDuration
) of the timer signal should last until the exposure of the sensor is completed. This can be realized by using the following formula: t
TimerDuration
= (t triggerdelay
– t
TimerDelay
) + t exposure
9.6.8 Frame Counter
The frame counter is part of the Baumer image infoheader and supplied with every image, if the chunkmode is activated. It is generated by hardware and can be used to verify that every image of the camera is transmitted to the PC and received in the right order.
45
9.7
Sequencer
9.7.1 General Information
A sequencer is used for the automated control of series of images using different sets of parameters. m A
A
B
B
C
C o z
◄ Figure 38
Flow chart of sequencer.
m - number of loop
passes n - number of set
repetitions o - number of
sets of parameters z - number of frames
per trigger
Sequencer Parameter:
The mentioned sets of parameter include the following:
▪ Exposure time
▪ Gain factor
▪ Output line
▪ Origin of ROI (Offset X, Y)
The figure above displays the fundamental structure of the sequencer module.
A sequence (o) is defined as a complete pass through all sets of parameters.
The loop counter (m) represents the number of sequence repetitions.
The repeat counter (n) is used to control the amount of images taken with the respective sets of parameters.
The start of the sequencer can be realized directly (free running) or via an external event
(trigger).
The additional frame counter (z) is used to create a half-automated sequencer. It is absolutely independent from the other three counters, and used to determine the number of frames per external trigger event.
▪
▪
▪
▪
The following timeline displays the temporal course of a sequence with: n = 5 repetitions per set of parameters o = 3 sets of parameters (A,B and C) m = 1 sequence and z = 2 frames per trigger
A B C
Figure 39 ►
Timeline for a single sequence n = 1 n = 2 z = 2 n = 3 z = 2 n = 4 n = 5 z = 2 n = 1 n = 2 z = 2 n = 3 n = 1 n = 2 z = 2
46
9.7.2 Baumer Optronic Sequencer in Camera xml-file
The Baumer Optronic seqencer is described in the category ing features:
“BOSequencer”
by the follow-
<Category Name="BOSequencer" NameSpace="Custom">
<pFeature>BoSequencerEnable</pFeature>
<pFeature>BoSequencerStart</pFeature>
<pFeature>BoSequencerRunOnce</pFeature>
<pFeature>BoSequencerFreeRun</pFeature>
<pFeature>BoSequencerSetSelector</pFeature>
<pFeature>BoSequencerLoops</pFeature>
<pFeature>BoSequencerSetRepeats</pFeature>
Enable / Disable
Start / Stop
Run Once / Cycle
Free Running / Trigger
Configure set of parameters
Number of sequences (m)
Number of repetitions (n)
<pFeature>BoSequencerFramesPerTrigger</pFeature>
Number of frames per trigger (z)
<pFeature>BoSequencerExposure</pFeature>
<pFeature>BoSequencerGain</pFeature>
</Category>
Parameter exposure
Parameter gain
9.7.3 Examples
9.7.3.1 Sequencer without Machine Cycle
C
C
Sequencer
Start
B
B
A
A
The figure above shows an example for a fully automated sequencer with three sets of parameters (A,B and C). Here the repeat counter (n) is set to 5, the loop counter (m) has a value of 2.
When the sequencer is started, with or without an external event, the camera will record
5 images successively in each case, using the sets of parameters A, B and C (which constitutes a sequence). After that, the sequence is started once again, followed by a stop of the sequencer - in this case the parameters are maintained
◄ Figure 40
Example for a fully automated sequencer.
47
48
9.7.3.2 Sequencer Controlled by Machine Steps (trigger)
C
C
Sequencer
Start
B
B
A
Figure 41 ►
Example for a half-automated sequencer.
A Trigger
The figure above shows an example for a half-automated sequencer with three sets of parameters (A,B and C) from the previous example. The frame counter (z) is set to 2. This means the camera records two pictures after an incoming trigger signal.
9.7.4 Capability Characteristics of Baumer-GAPI Sequencer Module
▪
▪
▪
▪
▪ up to 128 sets of parameters up to 65536 loop passes up to 65536 repetitions of sets of parameters up to 65536 images per trigger event free running mode without initial trigger
9.7.5 Double Shutter
This feature offers the possibility of capturing two images in a very short interval. Depending on the application, this is performed in conjunction with a flash unit. Thereby the first exposure time (t exposure
) is arbitrary and accompanied by the first flash. The second exposure time must be equal to, or longer than the readout time (t readout
) of the sensor. Thus the pixels of the sensor are recepitve again shortly after the first exposure. In order to realize the second short exposure time without an overrun of the sensor, a second short flash must be employed, and any subsequent extraneous light prevented.
Trigger
Flash
Exposure
Prevent Light
Readout
On Baumer VisiLine IP cameras this feature is realized within the sequencer.
In order to generate this sequence, the sequencer must be configured as follows:
Parameter
Sequencer Run Mode
Sets of parameters (o)
Loops (m)
Repeats (n)
Frames Per Trigger (z)
Setting:
Once by Trigger
2
1
1
2
9.8 Device Reset
The feature Device Reset corresponds to the turn off and turn on of the camera. This is necessary after a parameterization (e.g. the network data) of the camera.
The interrupt of the power supply ist therefore no longer necessary.
◄ Figure 42
Example of a double shutter.
49
Figure 43 ►
Timestamps of recorded images.
9.9 User Sets
Four user sets (0-3) are available for the Baumer cameras of the VisiLine IP series. User set 0 is the default set and contains the factory settings. User sets 1 to 3 are user-specific and can contain any user definable parameters.
These user sets are stored within the camera and can be loaded, saved and transferred to other cameras of the VisiLine IP series.
By employing a so-called "user set default selector", one of the four possible user sets can be selected as default, which means, the camera starts up with these adjusted parameters.
9.10 Factory Settings
The factory settings are stored in "user set 0" which is the default user set. This is the only user set, that is not editable.
9.11 Timestamp
The timestamp is part of the GigE Vision ® standard. It is 64 bits long and denoted in
Ticks *) . Any image or event includes its corresponding timestamp.
At power on or reset, the timestamp starts running from zero.
1123354
1123254
1123154
1123054
1122754
1122654
1122554
1122454
1122354
50
*) Tick is the internal time unit of the camera, it lasts 1 nsec.
10. Interface Functionalities
10.1 Device Information
This Gigabit Ethernet-specific information on the device is part of the Discovery-Acknowledge of the camera.
▪
▪
▪
▪
▪
▪
▪
Included information:
▪ MAC address
Current IP configuration (persistent IP / DHCP / LLA)
Current IP parameters ( IP address, subnet mask, gateway)
Manufacturer's name
Manufacturer-specific information
Device version
Serial number
User-defined name (user programmable string)
10.2 Baumer Image Info Header
The Baumer Image Info Header is a data packet, which is generated by the camera and integrated in the last data packet of every image, if chunk mode is activated.
In this integrated data packet are different settings for this image. BGAPI can read the
Image Info Header. Third Party Software, which supports the Chunk mode, can read the features in the table below. This settings are (not completely):
Feature
ChunkOffsetX
ChunkOffsetY
ChunkWidth
ChunkHeight
ChunkPixelFormat
Description
Horizontal offset from the origin to the area of interest (in pixels).
Vertical offset from the origin to the area of interest (in pixels).
Returns the Width of the image included in the payload.
Returns the Height of the image included in the payload.
Returns the PixelFormat of the image included in the payload.
ChunkExposureTime Returns the exposure time used to capture the image.
ChunkBlackLevelSelector Selects which Black Level to retrieve data from.
ChunkBlackLevel
ChunkFrameID
Returns the black level used to capture the image included in the payload.
Returns the unique Identifier of the frame (or image) included in the payload.
◄ Figure 44
Location of the Baumer
Image Info Header
51
10.3 Packet Size and Maximum Transmission Unit (MTU)
Network packets can be of different sizes. The size depends on the network components employed. When using GigE Vision ® - compliant devices, it is generally recommended to use larger packets. On the one hand the overhead per packet is smaller, on the other hand larger packets cause less CPU load.
The packet size of UDP packets can differ from 576 Bytes up to the MTU.
The MTU describes the maximal packet size which can be handled by all network components involved.
In principle modern network hardware supports a packet size of 1500 Byte, which is specified in the GigE network standard. "Jumboframes" merely characterizes a packet size exceeding 1500 Bytes.
Baumer VisiLine IP cameras can handle a MTU of up to 65535 Bytes.
IPG:
The IPG is measured in ticks.
An easy rule of thumb is:
1 Tick is equivalent to 1 Bit of data.
You should also not forget to add the various ethernet headers to your calculation.
10.4 Inter Packet Gap
To achieve optimal results in image transfer, several Ethernet-specific factors need to be considered when using Baumer VisiLine IP cameras.
Upon starting the image transfer of a camera, the data packets are transferred at maximum transfer speed (1 Gbit/sec). In accordance with the network standard, Baumer employs a minimal separation of 12 Bytes between two packets. This separation is called
"inter packet gap" (IPG). In addition to the minimal IPG, the GigE Vision ® standard stipulates that the IPG be scalable (user-defined).
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10.4.1 Example 1: Multi Camera Operation – Minimal IPG
Setting the IPG to minimum means every image is transfered at maximum speed. Even by using a frame rate of 1 fps this results in full load on the network. Such "bursts" can lead to an overload of several network components and a loss of packets. This can occur, especially when using several cameras.
In the case of two cameras sending images at the same time, this would theoretically occur at a transfer rate of 2 Gbits/sec. The switch has to buffer this data and transfer it at a speed of 1 Gbit/sec afterwards. Depending on the internal buffer of the switch, this operates without any problems up to n cameras (n ≥ 1). More cameras would lead to a loss of packets. These lost packets can however be saved by employing an appropriate resend mechanism, but this leads to additional load on the network components.
▲ Figure 45
Operation of two cameras employing a Gigabit
Ethernet switch.
Data processing within the switch is displayed in the next two figures.
◄ Figure 46
Operation of two cameras employing aminimal inter packet gap (IPG).
10.4.2 Example 2: Multi Camera Operation – Optimal IPG
A better method is to increase the IPG to a size of optimal IPG = (number of cameras-1)*packet size + 2 × minimal IPG
In this way both data packets can be transferred successively (zipper principle), and the switch does not need to buffer the packets.
Max. IPG:
On the Gigabit Ethernet the max. IPG and the data packet must not exceed 1
Gbit. Otherwise data packets can be lost.
◄ Figure 47
Operation of two cameras employing an optimal inter packet gap (IPG).
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10.5 Transmission Delay
Another approach for packet sorting in multi-camera operation is the so-called Transmission Delay.
Due to the fact, that the currently recorded image is stored within the camera and its transmission starts with a predefined delay, complete images can be transmitted to the
PC at once.
The following figure should serve as an example:
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Figure 48 ►
Principle of the transmission delay.
For the image processing three cameras with different sensor resolutions are employed – for example camera 1: VLG-12M.I, camera 2: VLG-20M.I, camera 3: VLG-02M.I.
Due to process-related circumstances, the image acquisitions of all cameras end at the same time. Now the cameras are not trying to transmit their images simultaniously, but – according to the specified transmission delays – subsequently. Thereby the first camera starts the transmission immediately – with a transmission delay "0".
10.5.1 Time Saving in Multi-Camera Operation
As previously stated, the transmission delay feature was especially designed for multicamera operation with employment of different camera models. Just here an significant acceleration of the image transmission can be achieved:
Figure 49 ►
Comparison of transmission delay and inter packet gap, employed for a multi-camera system with different camera models.
For the above mentioned example, the employment of the transmission delay feature results in a time saving – compared to the approach of using the inter packet gap – of approx. 45% (applied to the transmission of all three images).
10.5.2 Configuration Example
For the three employed cameras the following data are known:
Camera
Model
Sensor
Resolution
[Pixel]
VLG-12M.I 1288 x 960
VLG-20M.I 1624 x 1228
VLG-02M.I 656 x 490
Pixel Format
(Pixel Depth)
Resulting
Data Volume
[bit]
8
8
8
[bit]
9891840
15954176
2571520
Readout
Time
Exposure
Time
Transfer
Time (GigE)
[msec]
23.8
37
6.4
[msec]
32
32
32
[msec]
≈ 9.2
≈ 14.9
≈ 2.4
▪
▪
The sensor resolution and the readout time (t
The exposure time (t exposure readout
) can be found in the respective
Technical Data Sheet (TDS). For the example a full frame resolution is used.
) is manually set to 32 msec.
▪ The resulting data volume is calculated as follows:
Resulting Data Volume = horizontal Pixels × vertical Pixels × Pixel Depth
▪ The transfer time (t transferGigE
) for full GigE transfer rate is calculated as follows:
Transfer Time (GigE) = Resulting Data Volume / 1024 3 × 1000 [msec]
All the cameras are triggered simultaneously.
The transmission delay is realized as a counter, that is started immediately after the sensor readout is started.
Trigger
Camera 1
(TXG13) t exposure(Camera 1)
Timings:
A - exposure start for all cameras
B - all cameras ready for transmission
C - transmission start camera 2
D - transmission start camera 3 t readout(Camera 1)
Camera 2
(TXG06)
Camera 3
(TXG03) t transfer(Camera 1)* t exposure(Camera 2) t readout(Camera 2) t transferGigE(Camera 2) t exposure(Camera 3) t readout(Camera 3) t transferGigE(Camera 3)
* Due to technical issues
the data transfer of
camera 1 does not take
place with full GigE
speed.
TransmissionDelay
Camera 2
TransmissionDelay
Camera 3
◄ Figure 50
Timing diagram for the transmission delay of the three employed cameras, using even exposure times.
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56
In general, the transmission delay is calculated as: t
Transmissi onDelay ( Camera n )
= t exp osure ( Camera 1 )
+ t readout ( Camera 1 )
− t exp osure ( Camera n )
+ n
∑
n ≥ 3 t transferGi gE ( Camera n 1 )
Therewith for the example, the transmission delays of camera 2 and 3 are calculated as follows: t
TransmissionDelay(Camera 2)
= t exposure(Camera 1)
+ t readout(Camera 1)
- t exposure(Camera 2) t
TransmissionDelay(Camera 3)
= t exposure(Camera 1)
+ t readout(Camera 1)
- t exposure(Camera 3)
+ t transferGige(Camera 2) t
Solving this equations leads to:
TransmissionDelay(Camera 2)
= 32 msec + 23.8 msec - 32 msec
= 23.8 msec
= 7437750 ticks t
TransmissionDelay(Camera 3)
= 32 msec + 23.8 msec - 32 msec + 14.9 msec
= 38,7 msec
= 1209375 ticks
Notice
In BGAPI the delay is specified in ticks. How do convert microseconds into ticks?
1 tick = 1 ns
1 msec = 1000000 ns
1 tick = 0,000001 msec ticks= t
TransmissionDelay
[msec] / 0,000001 = t
TransmissionDelay
[ticks]
10.6 Multicast
Multicasting offers the possibility to send data packets to more than one destination address – without multiplying bandwidth between camera and Multicast device (e.g. Router or Switch).
The data is sent out to an intelligent network node, an IGMP (Internet Group Management
Protocol) capable Switch or Router and distributed to the receiver group with the specific address range.
In the example on the figure below, multicast is used to process image and message data separately on two differents PC's.
Multicast Addresses:
For multicasting Baumer suggests an adress range from 232.0.1.0 to
232.255.255.255.
◄ Figure 51
Principle of Multicast
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Internet Protocol:
On Baumer cameras IP v4 is employed.
Figure 52 ▲
Connection pathway for
Baumer Gigabit Ethernet cameras:
The device connects step by step via the three descr bed mechanisms.
10.7 IP Configuration
10.7.1 Persistent IP
A persistent IP adress is assigned permanently. Its validity is unlimited.
Notice
Please ensure a valid combination of IP address and subnet mask.
IP range:
0.0.0.0 – 127.255.255.255
128.0.0.0 – 191.255.255.255
192.0.0.0 – 223.255.255.255
Subnet mask:
255.0.0.0
255.255.0.0
255.255.255.0
These combinations are not checked by Baumer-GAPI, Baumer-GAPI Viewer or camera on the fly. This check is performed when restarting the camera, in case of an invalid
IP - subnet combination the camera will start in LLA mode.
* This feature is disabled by default.
10.7.2 DHCP (Dynamic Host Configuration Protocol)
The DHCP automates the assignment of network parameters such as IP addresses, subnet masks and gateways. This process takes up to 12 sec.
Once the device (client) is connected to a DHCP-enabled network, four steps are processed:
▪ DHCP Discovery
In order to find a DHCP server, the client sends a so called DHCPDISCOVER broadcast to the network.
DHCP:
Please pay attention to the
DHCP Lease Time.
Figure 53 ►
DHCP Discovery
(broadcast)
▪ DHCP Offer
After reception of this broadcast, the DHCP server will answer the request by an unicast, known as DHCPOFFER. This message contains several items of information, such as:
Information for the client
Information on server
MAC address offered IP address
IP adress subnet mask duration of the lease
58
Figure 54 ►
DHCP offer (unicast)
▪ DHCP Request
Once the client has received this DHCPOFFER, the transaction needs to be confirmed. For this purpose the client sends a so called DHCPREQUEST broadcast to the network. This message contains the IP address of the offering DHCP server and informs all other possible DHCPservers that the client has obtained all the necessary information, and there is therefore no need to issue IP information to the client.
◄ Figure 55
DHCP Request
(broadcast)
▪ DHCP Acknowledgement
Once the DHCP server obtains the DHCPREQUEST, an unicast containing all necessary information is sent to the client. This message is called DHCPACK.
According to this information, the client will configure its IP parameters and the process is complete.
DHCP Lease Time:
The validity of DHCP IP addresses is limited by the lease time. When this time is elapsed, the IP configuration needs to be redone.
This causes a connection abort.
10.7.3 LLA
LLA (Link-Local Address) refers to a local IP range from 169.254.0.1 to 169.254.254.254 and is used for the automated assignment of an IP address to a device when no other method for IP assignment is available.
The IP address is determined by the host, using a pseudo-random number generator, which operates in the IP range mentioned above.
Once an address is chosen, this is sent together with an ARP (Address Resolution Protocol) query to the network to to check if it already exists. Depending on the response, the IP address will be assigned to the device (if not existing) or the process is repeated.
This method may take some time - the GigE Vision ® standard stipulates that establishing connection in the LLA should not take longer than 40 seconds, in the worst case it can take up to several minutes.
◄ Figure 56
DHCP Acknowledgement (unicast)
LLA:
Please ensure operation of the PC within the same subnet as the camera.
10.7.4 Force IP *)
Inadvertent faulty operation may result in connection errors between the PC and the camera.
In this case "Force IP" may be the last resort. The Force IP mechanism sends an IP address and a subnet mask to the MAC address of the camera. These settings are sent without verification and are adapted immediately by the client. They remain valid until the camera is de-energized.
*) In the GigE Vision ® standard, this feature is defined as "Static IP".
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10.8 Packet Resend
Due to the fact, that the GigE Vision ® standard stipulates using a UDP - a stateless user datagram protocol - for data transfer, a mechanism for saving the "lost" data needs to be employed.
Here, a resend request is initiated if one or more packets are damaged during transfer and - due to an incorrect checksum - rejected afterwards.
On this topic one must distinguish between three cases:
10.8.1 Normal Case
In the case of unproblematic data transfer, all packets are transferred in their correct order from the camera to the PC. The probability of this happening is more then 99%.
Figure 57 ►
Data stream without damaged or lost packets.
10.8.2 Fault 1: Lost Packet within Data Stream
If one or more packets are lost within the data stream, this is detected by the fact, that packet number n is not followed by packet number (n+1). In this case the application sends a resend request (A). Following this request, the camera sends the next packet and then resends (B) the lost packet.
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Figure 58 ►
Resending lost packets within the data stream.
In our example packet no. 3 is lost. This fault is detected on packet no. 4, and the resend request triggered. Then the camera sends packet no. 5, followed by resending packet no. 3.
10.8.3 Fault 2: Lost Packet at the End of the Data Stream
In case of a fault at the end of the data stream, the application will wait for incoming packets for a predefined time. When this time has elapsed, the resend request is triggered and the "lost" packets will be resent.
In our example, packets from no. 3 to no. 5 are lost. This fault is detected after the predefined time has elapsed and the resend request (A) is triggered. The camera then resends packets no. 3 to no. 5 (B) to complete the image transfer.
10.8.4 Termination Conditions
The resend mechanism will continue until:
◄ Figure 59
Resending of lost packets at the end of the data stream.
▪
▪
▪
▪ all packets have reached the pc the maximum of resend repetitions is reached the resend timeout has occured or the camera returns an error.
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62
10.9 Message Channel
The asynchronous message channel is described in the GigE Vision ® standard and offers the possibility of event signaling. There is a timestamp (64 bits) for each announced event, which contains the accurate time the event occurred. Each event can be activated and deactivated separately.
10.9.1 Event Generation
Event
Gen<i>Cam™
ExposureStart
ExposureEnd
FrameStart
FrameEnd
Line0Rising
Line0Falling
Line1Rising
Line1Falling
Line2Rising
Line2Falling
Line3Rising
Line3Falling
Vendor-specific
EventError
EventLost
TriggerReady
TriggerOverlapped
TriggerSkipped
Description
Exposure started
Exposure ended
Acquisition of a frame started
Acquisition of a frame ended
Rising edge detected on IO-Line 0
Falling edge detected on IO-Line 0
Rising edge detected on IO-Line 1
Falling edge detected on IO-Line 1
Rising edge detected on IO-Line 2
Falling edge detected on IO-Line 2
Rising edge detected on IO-Line 3
Falling edge detected on IO-Line 3
Error in event handling
Occured event not analyzed t notready
elapsed, camera is able to process incoming trigger
Overlapped Mode detected
Camera overtriggered
10.10 Action Command / Trigger over Ethernet
The basic idea behind this feature was to achieve a simultaneous trigger for multiple cameras.
Therefore a broadcast ethernet packet was implemented. This packet can be used to induce a trigger as well as other actions.
Due to the fact that different network components feature different latencies and jitters, the trigger over the Ethernet is not as synchronous as a hardware trigger. Nevertheless, applications can deal with these jitters in switched networks, and therefore this is a comfortable method for synchronizing cameras with software additions.
The action command is sent as a broadcast. In addition it is possible to group cameras, so that not all attached cameras respond to a broadcast action command.
▪
▪
▪
▪
Such an action command contains: a Device Key - for authorization of the action on this device an Action ID - for identification of the action signal a Group Key - for triggering actions on separated groups of devices a Group Mask - for extension of the range of separate device groups
10.10.1 Example: Triggering Multiple Cameras
The figure below displays three cameras, which are triggered synchronously by a software application.
Action Command:
Since hardware release 2.1 the implemetation of the
Action Command follows the regulations of the GigE
Vision ® standard 1.2.
Another application of action command is that a secondary application or PC or one of the attached cameras can actuate the trigger.
◄ Figure 60
Triggering of multiple cameras via trigger over
Ethernet (ToE).
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11. Start-Stop-Behaviour
11.1 Start / Stop / Abort Acquisition (Camera)
Once the image acquisition is started, three steps are processed within the camera:
▪
▪ Determination of the current set of image parameters
▪ Exposure of the sensor
Readout of the sensor.
Afterwards a repetition of this process takes place until the camera is stopped.
Stopping the acquisition means that the process mentioned above is aborted. If the stop signal occurs within a readout, the current readout will be finished before stopping the camera. If the stop signal arrives within an exposure, this will be aborted.
Abort Acquisition
The acquisition abort represents a special case of stopping the current acquisition.
When an exposure is running, the exposure is aborted immediately and the image is not read out.
11.2 Start / Stop Interface
Without starting the interface, transmission of image data from the camera to the PC will not proceed. If the image acquisition is started before the interface is activated, the recorded images are lost.
If the interface is stopped during a transmission, this is aborted immediately.
11.3 Acquisition Modes
In general, three acquisition modes are available for the cameras in the Baumer VisiLine
IP series.
11.3.1 Free Running
Free running means the camera records images continuously without external events.
11.3.2 Trigger
The basic idea behind the trigger mode is the synchronization of cameras with machine cycles. Trigger mode means that image recording is not continuous, but triggered by external events.
This feature is described in chapter 4.6. Process Interface.
11.3.3 Sequencer
A sequencer is used for the automated control of series of images, using different settings for exposure time and gain.
12. Cleaning
Cover glass
Notice
The sensor is mounted dust-proof. Remove of the cover glass for cleaning is not necessary.
Avoid cleaning the cover glass of the sensor if possible. To prevent dust, follow the instructions under "Install lens".
If you must clean it, use compressed air or a soft, lint free cloth dampened with a small quantity of pure alcohol.
Housing volatile solvents
Caution!
Volatile solvents for cleaning.
Volatile solvents damage the surface of the camera.
Never use volatile solvents (benzine, thinner) for cleaning!
To clean the surface of the camera housing, use a soft, dry cloth. To remove persistent stains, use a soft cloth dampened with a small quantity of neutral detergent, then wipe dry.
13. Transport / Storage
Notice
Transport the camera only in the original packaging. When the camera is not installed, then storage the camera in original packaging.
Storage temperature
Storage Humidy
Storage Environment
-10°C ... +70°C ( +14°F ... +158°F)
10% ... 90% non condensing
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14. Disposal
Dispose of outdated products with electrical or electronic circuits, not in the normal domestic waste, but rather according to your national law and the directives 2002/96/EC and 2006/66/EC for recycling within the competent collectors.
Through the proper disposal of obsolete equipment will help to save valuable resources and prevent possible adverse effects on human health and the environment.
The return of the packaging to the material cycle helps conserve raw materials an reduces the production of waste. When no longer required, dispose of the packaging materials in accordance with the local regulations in force.
Keep the original packaging during the warranty period in order to be able to pack the device properly in the event of a warranty claim.
15. Warranty Notes
Notice
If it is obvious that the device is / was dismantled, reworked or repaired by other than
Baumer technicians, Baumer Optronic will not take any responsibility for the subsequent performance and quality of the device!
16. Support
If you have any problems with the camera, then feel free to contact our support.
Worldwide
Baumer Optronic GmbH
Badstrasse 30
DE-01454 Radeberg, Germany
Tel: +49 (0)3528 4386 845
Website: www.baumer.com
mail: [email protected]
17. Conformity
▪
▪
Baumer VisiLine IP cameras comply with:
CE,
▪
FCC Part 15 Class B,
RoHS
17.1 CE
We declare, under our sole responsibility, that the previously described Baumer cameras conform with the directives of the CE.
17.2 FCC – Class B Device
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occure in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off an on, the user is encouraged
▪
▪
▪ to try to correct the interference by one or more of the following measures:
Reorient or relocate the receiving antenna.
▪
Increase the separation between the equipment and the receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.
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Baumer Optronic GmbH
Baumer Optronic GmbH
Badstrasse 30
DE-01454 Radeberg, Germany
Phone +49 (0)3528 4386 0 · Fax +49 (0)3528 4386 86 [email protected] · www.baumer.com
DE-01454 Radeberg, Germany
Phone +49 (0)3528 4386 0 · Fax +49 (0)3528 4386 86 [email protected] · www.baumer.com
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