Noise Reduction
From apertus wiki
Record sensor temp alongside raw, apply different noise compensation depending on temp in post.
A Peltier can help build the profiles - by heating and cooling to a range of temperatures as needed.
Fixed Pattern Noise
General explanation: http://en.wikipedia.org/wiki/Fixed-pattern_noise
AXIOM Alpha measurements:
C0 + C1 * exposuretime
C0: Constant component of dark frame energy. If all pixels are read in parallel, the column uniformity might come from temporal variation of thermal noise.
C1: Exposure dependant component of the dark energy.
The row uniformity is probably due to each ADC response.
Images generated by https://github.com/Matthias-Fauconneau/serenity/blob/master/field-correction.cc using http://files.apertus.org/AXIOM-Alpha/darkframe-*.raw16.xz