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4.2 Pixel Response
4.2.1 Linear Response
The camera offers a linear response between input light signal and output grey level. This can
be modified by the use of LinLog
digital gain may be applied, as follows. Please see Table 3.2 for more model-dependent
information.
Black Level Adjustment
The black level is the average image value at no light intensity. It can be adjusted by the
software. Thus, the overall image gets brighter or darker. Use a histogram to control the
settings of the black level.
In CameraLink
cameras "BlackLevel".
®
4.2.2 LinLog
Overview
®
The LinLog
technology from Photonfocus allows a logarithmic compression of high light
intensities inside the pixel. In contrast to the classical non-integrating logarithmic pixel, the
®
LinLog
pixel is an integrating pixel with global shutter and the possibility to control the
transition between linear and logarithmic mode.
In situations involving high intrascene contrast, a compression of the upper grey level region
can be achieved with the LinLog
response. At high intensities the response changes to logarithmic compression (see Fig. 4.10).
The transition region between linear and logarithmic response can be smoothly adjusted by
software and is continuously differentiable and monotonic.
G r e y
V a l u e
1 0 0 %
0 %
Figure 4.10: Resulting LinLog2 response curve
4.2 Pixel Response
®
as described in the following sections. In addition, a linear
®
cameras the black level is called "BlackLevelOffset" and in GigE
®
technology. At low intensities each pixel shows a linear
L i n e a r
R e s p o n s e
V a l u e 1
V a l u e 2
S a t u r a t i o n
W e a k c o m p r e s s i o n
R e s u l t i n g L i n l o g
R e s p o n s e
S t r o n g c o m p r e s s i o n
L i g h t I n t e n s i t y
31
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