Author Topic: Zero or insignificant signal detected (empty image?)  (Read 6908 times)

Offline dhubbell

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Here's a little problem I ran into this morning with PI ImageIntegration.  After setting my calibration for all my LRGB frames and aligning them, I get this error message, when I try to stack my L Frames:

Quote
*** Error: A:/Files/My Astrophotography/Apogee A8050/2016-07/M8 Trifid/Processing/Calibrated/Registered/L/M8 and Trifid-0001_LUM_c_r.xisf: Zero or insignificant signal detected (empty image?)
<* failed *>

Now when I look at the image files, there is definitely data there.

I'm a rookie at PI, so it could be anything...I've tried to reset with Default settings, doesn't work.  Any ideas? 

I'm using PROCESS --> IMAGEINTEGRATION --> IMAGEINTEGRATION to stack the image.

Here's the data of the calibrated and Registered L images:
https://www.dropbox.com/s/mmwnomx8abrsfl0/M8%20and%20Trifid-L.zip?dl=0
Not a big download only 29MB

I didn't really see anything in the forums that covered this exact problem.  Hopefully with sample data, someone can give me a clue.

Thank you,

Doug

Offline pfile

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Re: Zero or insignificant signal detected (empty image?)
« Reply #1 on: 2016 July 04 14:15:25 »
somehow the files have been saved as 8-bit integer... which is pretty strange, since calibrated frames are usually saved out as 32-bit floating point xisf.

also strange because almost every camera's native format is 16-bit integer, so i wonder where along the line Uint8 was specified as the file save format. usually when you make your calibration masters with ImageIntegration the resultant files are 32-bit float. then when you calibrate, even though the input files are 16-bit integer, because they have been touched by 32b floating point files, the calibrated images also become 32-bit floating point.

what was your exact calibration flow?

rob

Offline dhubbell

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Re: Zero or insignificant signal detected (empty image?)
« Reply #2 on: 2016 July 04 23:26:25 »
Interesting...8 bit?  I didn't think that was possible using xisf. 

Anyway, I followed the calibration steps outline here:
https://youtu.be/zU5jJgjKuQQ

These steps don't use the Script --> Batch Processing --> BatchPreProcessing.

I'll double check, but, 8 bit?  Wow...rather unbelievable, but, thanks for pointing that out to me.  Doesn't make sense to process anything in 8 bit.

Perhaps 8 Bit is why "insignificant signal detected".  Better error message, "Hey don't use 8 Bit images!"

Offline Andres.Pozo

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Re: Zero or insignificant signal detected (empty image?)
« Reply #3 on: 2016 July 05 00:50:14 »
I have had this same problem with XIFS images in Int32 pixel format. These images could be integrated without problems after converting them to Float32.

It seems that there is some kind of problem in ImageIntegration when the input images are not Float32.

Offline msmythers

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Re: Zero or insignificant signal detected (empty image?)
« Reply #4 on: 2016 July 05 01:17:32 »
I ran Doug's files through ImageIntegration. Changing the Scale estimator would allow the files to proceed without error with all but 2 settings, Qn estimator or Iterative k-sigma. 


Mike

Offline Juan Conejero

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Re: Zero or insignificant signal detected (empty image?)
« Reply #5 on: 2016 July 05 01:29:00 »
Quote
It seems that there is some kind of problem in ImageIntegration when the input images are not Float32.

I can confirm this bug. It has not been reported before, AFAIK.

I'll release a bugfix update for all platforms as soon as possible. In the meanwhile, the workaround is simply to use a floating point sample format with ImageIntegration.

Thank you for detecting this issue, but please report bugs as soon as they happen (and please insist in the event that my workload prevents me from fixing them as quickly as needed).
Juan Conejero
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Offline Andres.Pozo

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Re: Zero or insignificant signal detected (empty image?)
« Reply #6 on: 2016 July 05 01:36:45 »
Thank you for detecting this issue, but please report bugs as soon as they happen (and please insist in the event that my workload prevents me from fixing them as quickly as needed).

I found it yesterday  ;).
I was trying to integrate new images taken this weekend with old images calibrated with another software that generates Int32 images.

Offline Juan Conejero

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Re: Zero or insignificant signal detected (empty image?)
« Reply #7 on: 2016 July 05 02:05:54 »
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I found it yesterday

Ah, Ok  :smiley:
Juan Conejero
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Offline Juan Conejero

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Re: Zero or insignificant signal detected (empty image?)
« Reply #8 on: 2016 July 05 04:39:05 »
Bug fixed. I have just released an update for all platforms. I'll upload source code changes to GitHub later.
Juan Conejero
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Offline dhubbell

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Re: Zero or insignificant signal detected (empty image?)
« Reply #9 on: 2016 July 05 06:30:57 »
Thank you!  I didn't realize it was a bug.  I thought I wasn't doing something right.  I had no idea.  I'll look forward to the patch.  Thank you very much Rob, Mike, Juan and Andres.

Offline dhubbell

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Re: Zero or insignificant signal detected (empty image?)
« Reply #10 on: 2016 July 05 06:47:56 »
I did the update, however, same results with the data set I placed for download.  I'll re-work and make sure the data is in 32bit.  I guess 8bit xisf files don't work in ImageIntegration. 

BTW, for reference the version:
01.08.04.1195 Ripley (X64)

Offline dhubbell

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Re: Zero or insignificant signal detected (empty image?)
« Reply #11 on: 2016 July 05 08:06:28 »
I ran Doug's files through ImageIntegration. Changing the Scale estimator would allow the files to proceed without error with all but 2 settings, Qn estimator or Iterative k-sigma. 


Mike

Yes, I confirmed, thanks Mike.  Other Scale Estimators worked, the only TWO that Did Not Work:
Iterative K-Sigma / Biweight Midvarance
and
Qn Estimator of Rousseuw and Croux

Doug

Offline Juan Conejero

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Re: Zero or insignificant signal detected (empty image?)
« Reply #12 on: 2016 July 05 08:16:53 »
There are two issues here: there was a bug, which Andrés has pointed out and is now fixed, and you have written calibrated and/or registered files in 8-bit integer format, which obviously is not what you want and need.

Quote
I did the update, however, same results with the data set I placed for download.

That happens because invalid statistical data for those files are still in ImageIntegration's cache. It actually doesn't matter because those 8-bit files are useless, but if you want to check them: Click the Preferences button on ImageIntegration (a tool button with the shape of a wrench), then click Clear Memory Cache Now and Purge Persistent Cache Now, then OK. The next time you integrate the same files all the statistical data will be recomputed, this time correctly.
Juan Conejero
PixInsight Development Team
http://pixinsight.com/

Offline dhubbell

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Re: Zero or insignificant signal detected (empty image?)
« Reply #13 on: 2016 July 05 08:39:18 »
Thank you Juan.

Offline pfile

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Re: Zero or insignificant signal detected (empty image?)
« Reply #14 on: 2016 July 05 09:29:12 »
glad that's sorted!

what kind of camera is it? i'm hard pressed to figure out a situation where the calibration process would yield an 8-bit image. at the very least i'd expect 16-bit images.

rob