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Alvium USB Cameras User Guide V3.6.4
Performance and troubleshooting
Additional compensation
If compensation limits are reached and you cannot decrease operating
temperature or exposure time, what can you do to keep signal quality high?
Measures for type 1 compensation
Alvium 1800 U-050m/c
supports compensation type 1. For additional
Black level compensation for 1800 U-050m/c
Typically, there is no measure to improve the image signal.
The rising black level shifts black and dark gray values to gray.
Measures for type 2 compensation
All other Alvium camera models support compensation type 2.
You can increase the margin size by using gain, with the following side effects:
• To give space to a larger margin, the effective pixel capacity decreases.
• White and light gray values are shifted down to gray.
Black level compensation for 1800 U-050m/c
Because the ON Semi PYTHON 480 sensor does not have a dark current
compensation,
Alvium 1800 U-050m/
c cameras have a typical black level value
drift, depending on exposure time and
DeviceTemperature
(measured at the
mainboard).
Table 109
shows the effect of the black level compensation. Should
additional compensation be needed, we recommend cooling the camera.
Temperature [°C]
ExposureTime [ms]
1
10
50
100
250
500
750
1,000
35
40
45
50
55
60
65
70
75
Full compensation
Partial compensation
Table 109: Exposure time and temperature affecting black level compensation
