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SHO Poll - Do you process before you combine?

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14 replies to this topic

#1 ChiTownXring

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Posted 21 July 2021 - 02:29 PM

I am just wondering what everyone is doing process wise if anything before they combine their SHO images into one color image?



#2 klaussius

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Posted 21 July 2021 - 02:38 PM

Not a SHO guru, but...

 

I do gradient reduction, some stretching (just linear fitting usually) and sometimes NR on each channel before combination.

 

I process the "L" channel separately (a combination of SHO, or just H, but processed separately to be used as L), and combine in "LSHO" fashion.



#3 jonnybravo0311

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Posted 21 July 2021 - 02:39 PM

Normally I crop, do Mure Denoise and DBE on each channel individually. Then I combine and do the remainder of my processing.


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#4 Becomart

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Posted 21 July 2021 - 02:48 PM

Normally I crop, do Mure Denoise and DBE on each channel individually. Then I combine and do the remainder of my processing.

Ditto apparent from I don't always use mure (sometimes it works..sometimes it doesn't)


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#5 Cometeer

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Posted 21 July 2021 - 02:49 PM

All of the below is done using Pixinsight 

 

Preprocessing Workflow:

  • WBPP for calibration only
  • Cosmetic Correction
  • Subframe Selector - per channel
  • Star Alignment (Registration) (on channels at once)
  • Image Integration - per channel
  • Drizzle Integration - per channel

 

Processing Workflow:

  • Dynamic Crop (use channel combination to create crop mask)
  • Linear Fit
  • DBE on each master
  • EZ Denoise on H,O,S masters
  • Arcsinstretch on H,O,S masters
  • Histogramtransform
  • Create synthetic lum from a SHO pixelmath combination 
  • EZ Decon on Lum
  • LRGB Combination w/ chrominance reduction on
  • Starnet
  • Final Curves
  • Dark structure enhance (if applicable)

 

I might be missing a step or two, but that’s the gist of it. 


Edited by Cometeer, 21 July 2021 - 02:54 PM.

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#6 jonnybravo0311

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Posted 21 July 2021 - 02:50 PM

Ditto apparent from I don't always use mure (sometimes it works..sometimes it doesn't)


That's why they invented the undo button tongue2.gif


Edited by jonnybravo0311, 21 July 2021 - 02:50 PM.


#7 Becomart

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Posted 21 July 2021 - 02:52 PM

That's why they invented the undo button tongue2.gif

Preach brother preach!



#8 pbmazda32

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Posted 21 July 2021 - 02:53 PM

I'm the opposite. Do everything on the individual channels, then combine. All I do after they are combined us some hue and saturation adjustments and I extract a luminance, make adjustment to it, and then combine it back to the color image. I am still very much challenged with pixinsight, but am getting better.

#9 Marcelofig

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Posted 21 July 2021 - 08:23 PM

Each channel can have a very different strength, generally Ha and Oiii are strong and Sii is weaker. Then I process each channel individually a little bit, trying to highlight as best as possible the details of each one. Basically:

 

- DBE
- Noise reduction
- Histogram Transformation
- Curves
- Stretching

 

Then I combine the channels and continue processing.



#10 tapfret

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Posted 21 July 2021 - 08:47 PM

What is SHO?



#11 Stelios

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Posted 21 July 2021 - 08:56 PM

What is SHO?

It's a narrowband color mapping -- Sii to Red, Ha to Green and Oiii to Blue (often subsequently manipulated to arrive at--or close to--the famous/infamous Hubble Palette). 

 

To answer the original question, I always do DBE on each channel, then (often but not invariably) deconvolution on each channel, and may or may not do linear fit. Occasionally I'll denoise a nasty channel and may do some star shrinkage. 

 

It's really hard to give a definite answer, as so much depends on the relative strength of the channels and the cleanness of the image.


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#12 DRK73

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Posted 21 July 2021 - 09:51 PM

Bookmarking this thread.....



#13 terry59

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Posted 22 July 2021 - 06:55 AM

I am just wondering what everyone is doing process wise if anything before they combine their SHO images into one color image?

All channels should be completely processed individually before combining them for further processing


Edited by terry59, 22 July 2021 - 06:56 AM.

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#14 ChiTownXring

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Posted 22 July 2021 - 10:27 AM

All of the below is done using Pixinsight 

 

Preprocessing Workflow:

  • WBPP for calibration only
  • Cosmetic Correction
  • Subframe Selector - per channel
  • Star Alignment (Registration) (on channels at once)
  • Image Integration - per channel
  • Drizzle Integration - per channel

 

Processing Workflow:

  • Dynamic Crop (use channel combination to create crop mask)
  • Linear Fit
  • DBE on each master
  • EZ Denoise on H,O,S masters
  • Arcsinstretch on H,O,S masters
  • Histogramtransform
  • Create synthetic lum from a SHO pixelmath combination 
  • EZ Decon on Lum
  • LRGB Combination w/ chrominance reduction on
  • Starnet
  • Final Curves
  • Dark structure enhance (if applicable)

 

I might be missing a step or two, but that’s the gist of it. 

I am going to definitely try your workflow as it looks quick but covers a lot of things I would not have done..



#15 Peregrinatum

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Posted 22 July 2021 - 10:42 AM

process starless, then combine immediately after stretching


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