Pixinsight Dynamic Background extraction adds Color artifacts [Deep Sky] Processing techniques · Jens · ... · 4 · 221 · 2

Jeroe 3.61
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I struggled with some color artifacts in my images, thinking it was my flats that are done incorrectly.
I've done some tests with no flats and the Color artifacts are still present.
After some more testing I've realized that the Dynamic Background extraction actually adds those artifacts in. Before DBE they are not present.
Does anyone know what this could be and how to eliminate it? looks like a wrong bit depth somewhere.
I've used DBE with my own way and also with the default settings, both generate those artifacts but both a little different.

what I get after DBE (of course streched to oblivion)

artifacts 2.jpg

What DBE gives me
artifacts.jpg
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andreatax 7.56
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DBE with very few sample points might be prone to err but you can always re-balance everything back to normal with BackgroundNeutralization and ColorCalibration afterward. Advise to avoid it in images with very little background such is this case. At most use linear ABE to correct for major gradients.
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whwang 11.57
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Is your image very dark to start with?

You may try to change the sample format from 32bit to 64bit to see if this improves.
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drmikevt 0.00
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I think you have other issues at play.  Look at those two images - the color artifacts in the first image are at an angle at the bottom of the image.  But, in the DBE image you posted, the lines are straight up and down (more or less).  It does not look like they line up.  

I agree with what is said above - it's very hard to impossible to a good background model on an image that is all nebula.  Most just skip this step.

Is the DBE image you posted linear or an STF stretch?  If it's STF, you can choose 'use 24bit' and it should look much better.  If it's linear, you can increase the smoothing factor, which should help.

Another possible issue is:  if the thing that needs to be extracted is from a flat-based error/artifact then you MUST use division instead of subtraction.  If it's sky gradient, use subtraction.  Your issue looks like a division problem. 

These days, I'm often using the very excellent and free AI-based program, Graxpert (graxpert.com) instead of DBE.  It plugs into PI and gives one-click AI based gradient extraction - give it a try and see it if works better for you.
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Maged 0.00
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If you can share a link with the stacked image that would be great..
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