Pike Technical Manual
V5.2.0
193
Description of the data path
Color correction is used to harmonize colors for the human eye. With other Allied
Vision (color) cameras so far, you had the opportunity to use it or to switch it off.
Pike cameras introduce for the first time the so-called color correction matrix.
This means: you are now 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 can not be overwritten (factory
setting).
Changing color correction coefficients
You can change the color-correction coefficients according to your own needs.
Changes are stored in the user settings.
Formula 4: Color correction
Note
•
A number of 1000 equals a color correction coefficient of
1.
•
To obtain an identity matrix set values of 1000 for the
diagonal elements an 0 for all others. As a result you get
colors like in the RAW modes.
•
The sums of all rows should be equal to each other. If not,
you get tinted images.
•
Color correction values range -1000 ... +2000 and are
signed 32 bit.
•
In order for white balance to work properly ensure that
the row sum equals 1000.
•
Each row should sum up to 1000. If not, images are less
or more colorful.
•
The maximum row sum is limited to 2000.
red*
Crr
red
Cgr
green
Cbr
blue
+
+
=
green*
Crg
red
Cgg
green
Cbg
blue
+
+
=
blue*
Crb
red
Cgb
green
Cbb
blue
+
+
=
