Author Topic: Introduced lines into debayered images.  (Read 720 times)

Offline Mariner10

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Introduced lines into debayered images.
« on: 2019 February 16 19:58:38 »
Hi all,
Attached are images of the Horsed Head, one is after cosmetic correction has been applied and everything looks okay the other is after the debayering process has been applied. The problem should be obvious.
I've never had this occur before and I was hoping subsequent processing would remove the lines and gradients (if that's the correct terminology).
All images were taken with a OSC QHY8L, calibration files added.
The debayer matrix for that camera is GBRG which was applied and has successfully been applied in the past.
I tried all other debayer combinations but they all gave either the same result or made the same result worse.
Blink did not give any indication that there was going to be an issue and even when I applied the debayer process to just one sub the same result occurred.
Is there a problem here or will this effect be removed later in the processing procedures. I have already tried DBE and applied ABE afterwards both of which took out the vignetting but the lines are now more obvious.
Regards, Steve.

Offline pfile

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Re: Introduced lines into debayered images.
« Reply #1 on: 2019 February 16 22:41:23 »
i think you need to stretch those and re-post them because they are so dark i can't see any of the artifacts you're talking about...

rob

Offline Mariner10

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Re: Introduced lines into debayered images.
« Reply #2 on: 2019 February 17 15:07:18 »
Sorry Rob, I forgot that they don't save stretched. I'll repost it when I get a moment.
Cheers.

Steve.

Offline Mariner10

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Re: Introduced lines into debayered images.
« Reply #3 on: 2019 February 19 00:23:26 »
Hi Rob,
So I've uploaded the stretched images (I hope) over two posts as I keep getting an error message that they are too large. You should be able now to see what I'm on about.
Cheers.

Offline Mariner10

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Re: Introduced lines into debayered images.
« Reply #4 on: 2019 February 19 00:24:09 »
This is the second image Rob.

Offline pfile

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Re: Introduced lines into debayered images.
« Reply #5 on: 2019 February 19 09:32:00 »
going to guess that these were registered and stacked and then debayered?

debayering needs to happen to each sub prior to registration.

rob

Offline Mariner10

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Re: Introduced lines into debayered images.
« Reply #6 on: 2019 February 19 14:30:20 »
Hi Rob, no, the process was cosmetic correction of all subs, debayered all subs and then registered them hoping that ABE or DBE might help resolve the problem.
I might have to go back to square one and start the process again. Even if the debayer matrix was wrong I don't think it should have done that to the images.
Cheers.

Offline pfile

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Re: Introduced lines into debayered images.
« Reply #7 on: 2019 February 19 15:47:28 »
well, this shouldn't happen obviously. maybe the CC step has somehow messed up the images. worth omitting that to see what happens.

rob

Offline chris.bailey

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Re: Introduced lines into debayered images.
« Reply #8 on: 2019 February 20 00:28:43 »
Would help if you could dropbox one of the baseline .fits files.

Chris

Offline Mariner10

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Re: Introduced lines into debayered images.
« Reply #9 on: 2019 February 20 18:36:32 »
Hi Rob,
I'll try giving the CC process a miss and see what happens then.

Hi Chris,
I'll drop one of the original subs into dropbox over the weekend. It's going to be stinking hot here so a perfect time to sit in the AC and do some processing.

Cheers.

Offline Mariner10

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Re: Introduced lines into debayered images.
« Reply #10 on: 2019 February 22 16:16:42 »
Hi Chris,
The link to the dropbox is https://www.dropbox.com/s/0tv07xkz7oiaa1f/HorseHead-1-600s-8-C0.fit?dl=0
Hope that works, I haven't used it before, if not let me know.

I'll try your suggestion this afternoon Rob.

Cheers.

Offline pfile

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Re: Introduced lines into debayered images.
« Reply #11 on: 2019 February 22 16:39:20 »
this isn't straight out of the camera though, is it? the FITS header indicates it was written out by Pixinsight.

the striped pattern appears to be in this image even before debayering... something is very weird here. plus it looks like it was saved with overscan areas preserved?

re: earlier w/ no problems vs. now, is it a new version of the capture software and/or the driver for this camera that differs between then and now?

rob


Offline Mariner10

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Re: Introduced lines into debayered images.
« Reply #12 on: 2019 February 22 18:34:35 »
Hi Rob,
No, the camera saves it as a fits file, I just checked all my other images that are waiting to be processed and they are all fit files if that's what you mean.
These were taken in 2016 and I haven't, to the best of my knowledge, updated the software for the camera. The laptop I use is kept with my gear and I only image remotely where there is no internet available so no auto-update availability.
I might try and see what happens if I try to process subs from last year and see if I get the same result.
Cheers.

Offline Mariner10

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Re: Introduced lines into debayered images.
« Reply #13 on: 2019 February 22 18:36:34 »
Forgot to add, I tried your suggestion of debayering before cosmetic correction was applied with the same result so it appears that the fault is right at the beginning. I took a single original image and applied debayer to it with the same result.

Offline pfile

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Re: Introduced lines into debayered images.
« Reply #14 on: 2019 February 22 22:06:32 »
well what i'm saying is that the file you posted seems to have been read into PI and then saved from PI, since the FITS header says:

 PROGRAM = 'PixInsight 01.08.06.1457' / Software that created this HDU           
 COMMENT PixInsight Class Library: PCL 02.01.11.0938                           
 COMMENT FITS module version 01.01.05.0433                                       

your capture software probably would not put those FITS keywords into the header.

something is funny with these images, i just don't know what. it's unusual to have those black borders all the way around straight out of the camera, and the lines seem to be there even before debayering...

rob