Dark frame and hot pixels

[andriy_melnykov]

Hello,

As I understand, SharpCap can ignore and interpolate hot pixels, if they are found in a loaded dark frame.
I would like to modify dark frame to exclude some other pixels from subs. Is it sufficient to set these pixels to 60000 for 16 bit raw format?
Background: I am studying some scientific articles regarding cmos sensors and want to implement some features. For example excluding not only hot pixels, but also pixels with anomaly high noise. I can realize these features in Python to generate or modify a dark frame. But, I need to find a way to say to SharpCap „do not use this pixel, handle it like hot pixel“.
Thanks!

[admin]

Hi,

yes, SharpCap takes a statistical view of the dark frame and flags any pixel more than 7 sigma above the mean as hot. When the time comes to do dark frame subtraction, the value of the light frame pixel is ignored at that point and a value is stolen from an adjacent pixel (of the same CFA colour if a RAW camera). Setting the dark pixel values to something very high should trigger that behaviour.

cheers,

Robin

[andriy_melnykov]

Thanks!
One more question regarding darks - if I have a color camera (ASI385mc) subs and combined dark from SharpCap have all RGGB tag in FITS file header (two times actually, color type and bayer pattern)
Is it important to have RGGB in the dark header, or can I use "monochrome" dark without RGGB tag?

[admin]

Hi,

SharpCap doesn't care about the FITS headers of the dark file (other than the image size, colour plane count and bit depth being correct). That means that a monochrome 'dark' frame should work just fine.

cheers,

Robin