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RMV Operations Manual Revision Copyright illunis LLC, 2014
Page 128
FAQ# 11:
How does the color version work?
The color versions of the RMV cameras are the same hardware as the
monochrome versions but incorporate a sensor that has a Bayer pattern. The
Bayer pattern is a RGB color pattern that consists of even lines with R-G-R-G-R-
G... pixel patterns and odd lines with G-B-G-B-G... pixel patterns. These colored
patterns are decoded and used to generate a RGB image. Your capture card or
application must process the Bayer pattern, as the camera does not.
The Bayer Pattern
The RMV color camera contains special ADC's, which can pre-gain the
Bayer pattern colors before they are converted to digital values. This allows for
the maximum dynamic color range as the white balance of the camera is per-
formed in the analog domain. The color gain registers provide an offset gain that
increase or decrease the gain from the main VGA amplifier. Consult the Analog
Devices AD9845A data sheet for more information at www.analog.com. Note that
there is a gain register for each of the two Green pixels in the Bayer pattern. You
must set both green gains to achieve correct white balance. In practice the green
color filters have slightly different responses must be set correctly to eliminate
color pattern problems. The color steering mode has no useful effect on a mono-
chrome camera, as it is not supported in the camera hardware. See the Analog
Devices™
datasheet
http://www.analog.com/productSelection/pdf/
AD9845A_0.pdf
for the AD9845 for specific register settings and modes.
FA
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RMV ADC Control with PxGA
PxGA Example
Color Control
The dialog box shows a typi-
cal setup for the PxGA control
for a average room white
balance. Reds are gained to
14 and Blues are Gained to
30. Usually one of the
Greens will need some gain
as well. Settings are depend-
ant on lighting and color tem-
perature.
Left Tap
Right Tap
Green 1
Red
Red
Green 1
Blue
Green 2
Green 2
Blue
R G1 R G1
G2 B G2 B
G2 B G2 B
R G1 R G1