E2v UNIIQA User Manual - page 33
U
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M
ANUAL
UNIIQA+
C
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09/2016
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33
White Balance
As described in the
Chapter §2.2
, the structure of the sensor differentiates Green pixels facing Blue or Red
pixels. Then the white balance is associated with 4 color Gains :
Red
Gain
Green
Red
Gain
Green
Blue
Gain
Blue
Gain
The Color Selection or enabling (Image Format Chapter) can affect the way you’re performing the white
balance : For example, if you disable the Blue and the Red color, the “White Balance” will be performed
only between the two Green Gains.
The dissociation of Green (blue) and Green (Red) is justified by the possible difference of response of the
two types of Green because of their respective neighbor color influence and then the necessity to tune
them separately.
As usual, for a perfect White balance, provide to the Camera a non-saturating white (gray) target in the
center of the sensor.
The White balance has to be performed after the Flat Field Correction as each color is performing its own
FFC with its own reference.
In any case, the best tuning of the Camera Gains is performed from the left to the right of the Gain Chain
described above : Preamp Gain first and quarter Gains last (if required).
The Following Gains are enabled by the White balance Enable switch :
Digital Red Gain (
Gain
with
GainSelector
=
DigitalRed
) : Set the Red Gain for the white balance. This
command is available in the CommCam “Color Management” section :
Read function : “r gwbr”;
Returned by the camera : Integer value from 0 to 1548. The corresponding Gain is
calculated as 20.log( 1 +
Write function : “w gwbr”
Digital Blue Gain (
Gain
with
GainSelector
=
DigitalBlue
) : Set the Blue Gain for the white balance.
This command is available in the CommCam “Color Management” section :
Read function : “r gwbb”;
Returned by the camera : Integer value from 0 to 1548. The corresponding Gain is
calculated as 20.log( 1 +
Write function : “w gwbb”
Digital Green
Red
Gain (
Gain
with
GainSelector
=
DigitalGreenR
) : Set the Green
Red
Gain for the white
balance. This command is available in the CommCam “Color Management” section :
Read function : “r gwbg”;
Returned by the camera : Integer value from 0 to 1548. The corresponding Gain is
calculated as 20.log( 1 +
Write function : “w gwbg”