Author Topic: DBE causes strong color cast  (Read 204 times)

Offline jamesRC

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DBE causes strong color cast
« on: 2019 October 11 11:16:54 »
Hi people,

I am processing an image of the Andromeda galaxy. It's an integrated image frm two sub-images with slightly different exposures. I had to dupe one of them and rename it to get the 3-file minimum PI requires for image integration. All were registered. When I run DBE, I get a very strong magenta cast. I tried removing green via SCNR, I also get a magenta cast. Why might this be, please? The image was already cropped, not a lot.

Thank you,
James

Offline jamesRC

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Re: DBE causes strong color cast
« Reply #1 on: 2019 October 11 13:17:53 »
Hello,

I found a way around the above problem. It may sound irrational but whatever works is good. I split the RGB image into separate  channels, then recombined the channels again. Whatever the heck happened, I got what seems to be a nice straightforward image showing the color hiding in the original. Why the heck did that work?  ;D :D

James

Offline jamesRC

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Re: DBE causes strong color cast
« Reply #2 on: 2019 October 11 18:29:59 »
on we go-

Actually, the image I got by separating and then recalibrating color channels, was way too harsh and contrasty. I still have my original question, why does background neutralization put a strong magenta cast in my image? I was viewing it with STF and the links button was NOT depressed, so thats not it. Help, please. Good image in the making once I get past this.

James

Offline pfile

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Re: DBE causes strong color cast
« Reply #3 on: 2019 October 11 19:05:56 »
i think this means you set the background threshold too high and so didn't capture all 3 channels background levels when you ran BN.

rob

Offline jamesRC

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Re: DBE causes strong color cast
« Reply #4 on: 2019 October 11 19:16:24 »
Thank you, rob.

You give me a starting point I need!

take care
James

Offline Geoff

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Re: DBE causes strong color cast
« Reply #5 on: 2019 October 11 20:44:45 »
Hi people,

I am processing an image of the Andromeda galaxy. It's an integrated image frm two sub-images with slightly different exposures. I had to dupe one of them and rename it to get the 3-file minimum PI requires for image integration.
Thank you,
James

A bit off topic: you should duplicate both images and integrate the resulting 4 images. If you duplicate just one of them, then it contributes twice as much signal as the other.
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Offline pfile

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Re: DBE causes strong color cast
« Reply #6 on: 2019 October 11 22:26:38 »
Thank you, rob.

You give me a starting point I need!

take care
James

sorry, i meant to say "too *low* and didn't capture all 3 channels"... setting it too high would pick up background and signal as well.

getting old...

also geoff's point is a good one, you should dupe each one to get 4 images if you only have 2.

rob

Offline jamesRC

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Re: DBE causes strong color cast
« Reply #7 on: 2019 October 12 19:50:20 »
Everybody,

thank you for your continued support. I'm "still working on it". Once, i was poking at STF and BN, just doing and undoing, and suddenly got the good image I wanted from BN.  Couldn't duplicate it, still trying.

James