Baumer VCXG - Fixed Pattern Noise Correction (FPNC)

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9.1.4 Fixed Pattern Noise Correction (FPNC)
CMOS sensors exhibit nonuniformities that are often called xed pattern noise (FPN).
However it is no noise but a xed variation from pixel to pixel that can be corrected. The
advantage of using this correction is a more homogeneous picture which may simplify the
image analysis. Variations from pixel to pixel of the dark signal are called dark signal non-
uniformity (DSNU) whereas photo response nonuniformity (PRNU) describes variations
of the sensitivity. DNSU is corrected via an offset while PRNU is corrected by a factor.
The correction is based on columns. It is important that the correction values are comput-
ed for the used sensor readout conguration. During camera production this is derived for
the factory defaults. If other settings are used (e.g. different number of readout channels)
using this correction with the default data set may degrade the image quality. In this case
the user may derive a specic data set for the used setup.
FPN Correction Off FPN Correction On
9.1.4.1 VCXG
Camera Type FPNC
Monochrome
VCXG-53M ■
Color
VCXG-53C ■
9.1.4.2 VCXU
Camera Type FPNC
Monochrome
VCXU-23M □
VCXU-50M □
Color
VCXU-23M □
VCXU-50C □