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Permanent stretch process/script

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6 replies to this topic

#1 dchamb

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Posted 30 November 2021 - 11:32 AM

In PixInsight, is there a process or script that can automatically permanently stretch an image? I know I can stretch an image by using STF and applying the instance to HistogramTransformation, and maybe I'm just a bit lazy but I'd like to see a process or script that combines these functions. I don't think it can be done in a Process Container.

#2 AbsolutelyNot

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Posted 30 November 2021 - 12:05 PM

Soft Stretch in the EZ Processing Suite will do this.

 

eta the results are not exactly the same as STF/HT.


Edited by AbsolutelyNot, 30 November 2021 - 12:10 PM.

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#3 kathyastro

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Posted 30 November 2021 - 12:13 PM

I find the STF stretch to be too harsh for a final image.  I just manually adjust the sliders in the Histogram Stretch.  Sometimes I will use a Masked Stretch, which is a one-button process, though it typically does not stretch enough, and the image needs tweaking afterwards.


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#4 Jared

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Posted 30 November 2021 - 12:35 PM

The problem is that stretching is very much a “personal taste” process, so there is no script that will provide the best results for all images.

#5 gatsbyiv

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Posted 30 November 2021 - 08:50 PM

PixInsight actually has exactly the function you seek:  AutoHistogram.  Try these settings:  

  • Enable Histogram clipping and leave the values at their defaults (0.010).
  • Change the stretch method to "Rational Interpolation (MTF)" and set the median value slider to 0.2.

That should pretty much give you what you are looking for.  


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#6 alpal

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Posted 30 November 2021 - 10:29 PM

I use NASA FITS liberator to do the stretching:

 

https://esahubble.or...r/download_v30/



#7 dchamb

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Posted 30 November 2021 - 10:34 PM

PixInsight actually has exactly the function you seek: AutoHistogram. Try these settings:

  • Enable Histogram clipping and leave the values at their defaults (0.010).
  • Change the stretch method to "Rational Interpolation (MTF)" and set the median value slider to 0.2.
That should pretty much give you what you are looking for.

Thank you! Looks like what I am looking for. I'll give it a try!


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