SW-2000M-CL-65
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5.2
Operating Modes
The cameras can be configured to offer several operating modes that are fundamentally
different from each other. The operating mode is configured upon start-up and can only be
changed by issuing a new mode selection command and rebooting the camera.
5.3
DSNU Corrector
DSNU (Dark Signal Non-uniformity) describes the pixel specific differences of response in dark,
while PRNU (Photo Response Non-uniformity) respectively describes the pixel specific
differences of response to equal amounts of light falling onto all the pixels. Both are basic
sensor- and pixel-specific imperfections, which can be characterized and minimized. DSNU is
corrected already during production. Users may use the FFC function to further adapt the
camera into existing lighting conditions, if necessary.
5.4
Offset and gain stage
This block first shifts the digital pixel value up or down and then applies a digital gain. The
result is limited to stay between zero and the maximum digital value.
5.5
Test Pattern Generator
The SW-2000M-CL-65 can send out five, defined test patterns instead of the real imaged lines
for purposes like interfacing and problem analysis. The patterns replace the image data and
can thus be used also to test the following blocks. Original, full patterns are available after
switching off the FFC, ROI and binning. Test data is also affected by the readout direction
selection.
5.6
Flat Field Corrector, FFC
Factory calibrated DSNU corrector minimize pixel specific differences in darkness. There is no
use to correct the PRNU as a factory setting as it is less than the noise. Real applications only
rarely can provide equal amounts of light for all pixels. This is caused mainly by effects like
uneven distribution of light (light profile) or properties of lenses like vignetting. Pixels at the
center region tend to get more light, while the intensity decreases towards both ends of the
line image sensor.
The compensation method called Shading Correction results in a flat, equal response to light
under the same conditions in which the calibration routine was run. It is generally thought of as
a coarse correction to regionally scale or gain the pixel responses without paying attention to
any pixel-specific differences. Also, generally, a method called Flat Field Correction (FFC) is
used for operations where a similar correction is done more precisely and for each pixel