Quote:
Originally Posted by pmrid
G'day Colin. Not sure what PRNU is. Another job for Google.
Peter
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Come to think of it, I think PRNU is the wrong term in this situation. Walking noise is FPN, got my acronyms all mixed up
FPN is Fixed Pattern Noise. CMOS sensors show it a lot more than CCDs do and that is mostly due to the lower read noise of CMOS. FPN tends to show itself in lower SNR areas (the background).
A little while ago I did a whole lot of 0.1s exposures on the star Eta Carina to capture the nebulosity surrounding it. Because I didn't dither even the "bright" Eta Carina Nebula was really faint in the image and was destroyed by FPN.
Dark and flat calibration really helps to mitigate it but ultimately you need dithering to average it out entirely.