PixInsight Forum

PixInsight => General => Topic started by: llpastro on 2015 June 27 13:35:06

Title: Problem with Image Calibration
Post by: llpastro on 2015 June 27 13:35:06
This is a continuation of my previous posts under "Problem Calibrating, Aligning, and Integration".  The problem lies in the image calibration process.  So far no one has responded to my need for help.  At this point until I solve the problem, I am forced to calibrate images outside of PI with other software.  I have spent hours in the last three days troubleshooting this problem with no resolution except to clarify what the issue is.  I have tried several different images with no change.  I cannot obtain a good calibrated image using either BPP or ImageCalibration.  The images open as pure black backgrounds and pure white stars.  Today a resorted to using ImageCalibration and ImageIntegration.  I used Vicent Peris' recommendations for Bias, Flat, and Dark master creation from his online tutorial about Master Calibration Frames.  The result for the bias, darks, and flats was good.  But calibrating the lights is the problem.  I am getting the same result as when I tried BPP for calibration only.  Attached are two images.  One is raw from an ST-10 CCD camera Stretched and the other is the result of calibration (stretched or not makes little difference).

Can anyone help?  I am just getting started with PI and and things have been going fine until now and now I am bewildered.  I attended Vicent's extensive 6 day workshop a couple of weeks ago and had no problems doing this then.  That was with a different computer and to make sure I tried this on that computer also.  Results are the same on both computers.

Larry
Title: Re: Problem with Image Calibration
Post by: Zocky on 2015 June 27 13:54:16
Maybe it would be the best solution if you upload some of your files (light, bias, dark, flat), so we can take a look and try to calibrate on our own.
Title: Re: Problem with Image Calibration
Post by: llpastro on 2015 June 27 14:11:53
Would the calibration masters and one light frame be enough?  Where can I upload that much data?  Limited here to 512K.  I don't have my own download site for others to access.

Larry
Title: Re: Problem with Image Calibration
Post by: msmythers on 2015 June 27 14:22:42
Larry

Zocky is correct in that in order to figure out the issue there is the need for original raw data. A couple of days ago there was a posting with a similar issue but completely different cameras. The issue turned out to be a compatibility(possible setting) problem with the capture software and PI. You might want to look at that posting on the methods used to determine the problem. I'm not saying that you have the same problem but you or others will need to see the actual data before guessing at a solution in this case.

http://pixinsight.com/forum/index.php?topic=8639.0 (http://pixinsight.com/forum/index.php?topic=8639.0)

You can upload to sites like Google drive, DropBox, Box and so on. You can also get access to the PI shared server Endor I believe but you do have to request access. Most people just use one of the many free services that are available these days.

 


Mike
Title: Re: Problem with Image Calibration
Post by: Zocky on 2015 June 27 14:36:27
Would the calibration masters and one light frame be enough?  Where can I upload that much data?  Limited here to 512K.  I don't have my own download site for others to access.

Larry
One light will be OK, but please upload a few from dark, bias and flat (please exclude calibration masters).
As Mike said, you can use Dropbox, Google drive......
Title: Re: Problem with Image Calibration
Post by: llpastro on 2015 June 27 15:17:58
I think I have this download process figured out.  Here is the link to Dropbox:

 https://www.dropbox.com/sh/h0uyxcrzjldtr7h/AAD5P68PhV49D-PbnIXIyN2_a?dl=0

Larry
Title: Re: Problem with Image Calibration
Post by: msmythers on 2015 June 27 16:09:36
Larry

I had no problem with your files. I used BPP to calibrate. I then use StarAlignment because of the hot pixels and ImageIntegration. Here are screen dumps of the settings I used. The Bias and Flats used the same settings in BPP. The image is nothing more then STF applied to HistogramTransformation.


Mike
Title: Re: Problem with Image Calibration
Post by: Zocky on 2015 June 27 16:14:06
Although dark frames are missing, everything works just fine. I didn't use BPP.
And this is my result. HT only.
Title: Re: Problem with Image Calibration
Post by: llpastro on 2015 June 27 16:17:52
Oops.  I forgot to include the darks in Dropbox.

Larry
Title: Re: Problem with Image Calibration
Post by: llpastro on 2015 June 27 16:22:27
That was a fortuitous oversight by not including the darks.  I tried calibration without a master dark and the image looks correct.  Halleluiah!  Looks like I have a problem with the darks.  I am going to upload some darks for anyone who can might look at them to see where the problem is.

Larry
Title: Re: Problem with Image Calibration
Post by: llpastro on 2015 June 27 16:28:26
Try it now using darks if you would please.  The link is still :
   
 https://www.dropbox.com/sh/h0uyxcrzjldtr7h/AAD5P68PhV49D-PbnIXIyN2_a?dl=0

Larry
Title: Re: Problem with Image Calibration
Post by: Zocky on 2015 June 27 16:35:31
Try it now using darks if you would please.  The link is still :
   
http://pixinsight.com/forum/index.php?topic=8639.0

Larry
Is provided link OK? It leads to another thread on forum, not to Dropbox.
Title: Re: Problem with Image Calibration
Post by: llpastro on 2015 June 27 16:41:17
Don't know what happen to link address but here it is.

 https://www.dropbox.com/sh/h0uyxcrzjldtr7h/AAD5P68PhV49D-PbnIXIyN2_a?dl=0

Larry
Title: Re: Problem with Image Calibration
Post by: llpastro on 2015 June 27 17:18:13
I did another test using the darks after I renamed them by removing the work OIII in the name.  This must have confused the algorithm.  Not sure why the filter name showed up in the image name for a dark frame.  Making progress.  Any additional insights anyone has will be appreciated.

Thanks to all who have replied so far as the dialog has helped.  I would still appreciate others using some of the dark data to confirm my suspicions
Title: Re: Problem with Image Calibration
Post by: Zocky on 2015 June 27 17:22:46
So far I am getting a dark image after ImageCalibration, using master dark. I will try to rename dark files.
Title: Re: Problem with Image Calibration
Post by: Zocky on 2015 June 27 17:30:18
I have renamed dark files, made new Master dark, run ImageCalibration again, but the resulting image is still very dark.
Title: Re: Problem with Image Calibration
Post by: msmythers on 2015 June 27 17:35:13
I ran the entire process in BPP. I did not rename the darks. I got a normal integrated image. Again I used STF and then applied it to HistogramTransformation.

Mike
Title: Re: Problem with Image Calibration
Post by: Zocky on 2015 June 27 17:42:32
I have forgot to check Calibrate, in Master dark section.
Now is working as should be.
Title: Re: Problem with Image Calibration
Post by: msmythers on 2015 June 27 17:50:44
And just to be complete here are the BPP screens except for Bias. Bias, Dark and Flats had the same settings.


Mike