Andrey,
I read up a bit and did few experiments and it looks like it should be
solvable with a flat field correction (image diveded through a
normalized grey card measurement picture) combined with darkframe and
bias frame substraction...I do not have a useful workflow for that yet...
However I think a (calibrateable) in-camera/in-FPGA correction
possibility would not be a bad idea (especially if the code is already
there)
best,
m,-
the pattern changes depending on which line-pair is used. but the
output is not necessarily any better...
I see. So it looks like pixel fixed-pattern noise. There are two ways
how to fight it.
One is to resurrect another part of unused FPGA code - the one that
can subtract/multiply the fixed values from the image pixels (that will
also need some calibration).
Second - with post-processing. In that case you should rather use jp46
format where pixels are not interpolated. First step - eliminate
additive parameter - you can get it if you average multiple line pairs
of the grey card or (even better) - disable autoexposure and white
balance (if you use them) and close the lens. For such measurements you
need to un-apply gamma (you can do it in ImageJ plugin) so the
background subtraction will take place with linear pixel values (setting
gamma=1 in the camera would kill the dynamic range)
Andrey
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