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Review of Camera Performance and Features
White Balancing
Relevant Features:
After performing PRNU calibration using the peak value as the target for each color, this may result
in each color having a different level even though the target may be white. The difference is caused
by the spectral content of the light source in combination with the spectral characteristics of the
cameras color filters. The White Balance feature can be used to bring all colors to the same level as
that of the highest color.
When performing white balance, the highest response color will be assigned the gain of 1x and the
other two color-gains will be adjusted to establish white balance. If the user had higher gains
applied, these will be over-written. If the user wants to subsequently increase the gain, they should
use the Camera Control > Color Selector feature and select System Gain. The gain feature will then
show the highest of the three color-gains being used. The user can then increase this gain and the
other two color-gains will be proportionally adjusted to maintain white balance.
Note
: running a PRNU calibration set to achieve a common target level for each
color will produce the same result. However, this action will introduce additional
gains into the PRNU coefficient and reduce their effective correction range and may
result in a color imbalance when changing camera direction. Therefore, it is
recommended to use the peak PRNU followed by white balance
.
White Balance Region of Interest
Typically, a white or neutral gray target is put in front of the camera while performing a white
balance. In some cases, this is not possible, or it may be desired that the white balance is
performed while acquiring the targeted object.
Figure 13. White Balance ROI Example
Potential White Balance ROI
