Instruction manual
Guppy PRO Technical ManualV4.1.0
116
Description of the data path
Color correction is needed to eliminate the overlap in the color channels. This
overlap is caused by the fact that:
• Blue light: is seen by the red and green pixels on the CCD
• Red light: is seen by the blue and green pixels on the CCD
• Green light: is seen by the red and blue pixels on the CCD
The color correction matrix subtracts out this overlap.
Color correction in Allied Vision cameras
In Allied Vision cameras the color correction is realized as an additional step in
the process from the sensor data to color output.
Color correction is used to harmonize colors for the human eye.
Guppy PRO cameras have the so-called color correction matrix. This means: you
are able to manipulate the color-correction coefficients yourself.
Color correction: formula
Before converting to the YUV format, color correction on all color models is car-
ried out after Bayer demosaicing via a matrix as follows:
GretagMacbeth ColorChecker
Sensor-specific coefficients C
xy
are scientifically generated to ensure that Gre-
tagMacbeth™ ColorChecker® colors are displayed with highest color fidelity and
color balance.
These coefficients are stored in user set 0 and cannot be overwritten (factory set-
ting).
Changing color correction coefficients
You can change the color-correction coefficients according to your own needs.
Changes are stored in the user settings.
Formula 5: Color correction
red* Crr red Cgr green Cbr blue++=
green* Crg red Cgg green Cbg blue++=
blue* Crb red Cgb green Cbb blue++=