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Image Processing Challenges / Flats Correction on M81
« on: 2019 June 12 12:28:34 »
Hello Team!
I'm fairly new to the PI game. I started my first image in 2016 with PI but have only done 3 or 4 pictures using the software in total. On this one, I am having a real hard time in pre-processing. When using flats to calibrate my light frames, I seem to get clean subs for my the L channel, but all my colour channels have this ghosting as if the Flat is inverted against the image or overcorrecting somehow. Here's what I've tried so far:
Creating new Master Flats using lower or higher skewed ADUs of the flat sub frames
Creating new Master Flats without the bias or master darks (in case they were messing them up somehow)
Adjusting the image integration for the master flat using different normalizations (this was the only thing that seemed to make an impact on the final version but even then wasn't quite right)
I have the raw data and the flats linked below. The flats are twilight flats.
https://drive.google.com/open?id=1e8WwcpXAjPDaSY6AwSNeNa6HnKYOEkXb
I have added two sample subs as an example. One of from the L Channel and another from R
Thanks everyone! I'd appreciate any help
-Matthew
I'm fairly new to the PI game. I started my first image in 2016 with PI but have only done 3 or 4 pictures using the software in total. On this one, I am having a real hard time in pre-processing. When using flats to calibrate my light frames, I seem to get clean subs for my the L channel, but all my colour channels have this ghosting as if the Flat is inverted against the image or overcorrecting somehow. Here's what I've tried so far:
Creating new Master Flats using lower or higher skewed ADUs of the flat sub frames
Creating new Master Flats without the bias or master darks (in case they were messing them up somehow)
Adjusting the image integration for the master flat using different normalizations (this was the only thing that seemed to make an impact on the final version but even then wasn't quite right)
I have the raw data and the flats linked below. The flats are twilight flats.
https://drive.google.com/open?id=1e8WwcpXAjPDaSY6AwSNeNa6HnKYOEkXb
I have added two sample subs as an example. One of from the L Channel and another from R
Thanks everyone! I'd appreciate any help
-Matthew