astro pixel processor

General discussion about StarTools.

Re: astro pixel processor

Postby micheleorsini » Mon Nov 06, 2017 7:41 pm

Reopening this thread because I followed the Rowland workflow on a different subject, also I tried to work with the Scott Rosens (viewtopic.php?f=12&t=1149) method.

First, I did my "best" with the workflow I'm used to.

Then I attempted the Scott Rosen workflow but the result was clearly below my best. The point here is that I spent hours in in refining my best so the comparison wasn't meaningful.

Instead, the Rowland suggested workflow can be compared very well with my "best" image because it involves only the initial composition/opening.

Here is what I did: split the image in LRGB, then use the LRGB module with pixel blur of 5px and finally follow *exactly* (except for saturation that has been pushed a little more) the steps that lead to my "best" to see what happens

Results:

my "best": https://www.dropbox.com/s/j0wij75iuj1ol ... .tiff?dl=0

LRGB: https://www.dropbox.com/s/wqsij02l6c4j7 ... .tiff?dl=0

original fits file: https://www.dropbox.com/s/rgqshavbznjgi ... 1.fts?dl=0

Now, as you can see, the "best" and the LRGB are nearly identical in details because I used the same steps in Startools modules, what I was expecting to see was lower noise in the LRGB but it seems to me that noise is equivalent in the two images.

The Rowland "rationale" behind his workflow is crystal clear, so, I bet, there is something in what I did that canceled its beneficial effects, or, inversely, something that I did not, for exploiting the advantage of lower color noise, e.g. maybe LRGB allowed me to push more on saturation without increasing noise

thoughts?

Michele
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Re: astro pixel processor

Postby Rowland » Tue Nov 07, 2017 9:32 am

Hi Michele.

Interesting comparison. The LRGB technique is intended to provide more control over saturation and not necessarily a guarantee of less noise. The 5 Pixel RGB blur seemed appropriate for the Veil rather than a fixed technique.

As it turns out, your 'best' has less noise than the LRGB. All the same, I will make further comparisons and report back.

EDIT: preliminary results indicate less noise at 400% colour saturation with LRGB, than the RGB at 275%. But I will need to verify.
Rowland
 
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Re: astro pixel processor

Postby micheleorsini » Tue Nov 07, 2017 11:22 am

Wow Rowland, thank you

To me, the "added value" of splitting + recombining is clear, now

I used not to touch saturate param because ... I don't know!! most probably because I'm lazy :-)

But now that I saw an image with higher saturation I think I'm going to use it ... and to be effective I will use your suggested LRGB composition!

Michele
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Re: astro pixel processor

Postby Rowland » Wed Nov 08, 2017 8:30 am

The results are in.

There's not a huge difference in appearance between the RGB at 275% and the LRGB at 400%, saturation.

M31stRGB.jpg
M31stRGB.jpg (265.31 KiB) Viewed 154 times

M31stLRGB400.jpg
M31stLRGB400.jpg (261.44 KiB) Viewed 154 times

Total noise = SquareRoot of Read^2 + Dark^2
Noise analysis - referring to the sumOfsquares, indicates less noise in the LRGB at 400% saturation
M31RGB-LRGB.png
M31RGB-LRGB.png (131.1 KiB) Viewed 154 times


StarTools log for both images - the same very basic work flow steps. I didn't use AutoDev, just a stretch in Dev.
Code: Select all
-----------------------------------------------------------
StarTools 1.4.329
Tue Nov  7 19:32:23 2017
-----------------------------------------------------------
File loaded [/home/geoland/Astrophotography/michele/20170920_M31.fts].
---
--- Bin
Parameter [Scale] set to [(scale/noise reduction 50.00%)/(400.00%)/(+2.00 bits)]
--- Crop
Parameter [X1] set to [56 pixels]
Parameter [Y1] set to [58 pixels]
Parameter [X2] set to [2546 pixels (-58)]
Parameter [Y2] set to [1688 pixels (-50)]
--- Develop
Parameter [White Calibration] set to [Use Stars]
Parameter [Gamma] set to [1.00]
Parameter [Skyglow] set to [0 %]
Parameter [Digital Development] set to [80.28 %]
Parameter [Blue Luminance Contrib.] set to [100 %]
Parameter [Green Luminance Contrib.] set to [100 %]
Parameter [Red Luminance Contrib.] set to [100 %]
Parameter [Dark Anomaly Headroom] set to [5 %]
Parameter [Dark Anomaly Filter] set to [2.0 pixels]
--- Wipe
Parameter [Mode] set to [Correct Color & Brightness]
Parameter [UNKNOWN] set to [Yes]
Parameter [Precision] set to [256 x 256 pixels]
Parameter [Dark Anomaly Filter] set to [1 pixels]
Parameter [Drop Off Point] set to [100 %]
Parameter [Corner Aggressiveness] set to [100 %]
Parameter [Aggressiveness] set to [75 %]
--- Develop
Parameter [White Calibration] set to [Use Stars]
Parameter [Gamma] set to [1.00]
Parameter [Skyglow] set to [0 %]
Parameter [Digital Development] set to [88.96 %]
Parameter [Blue Luminance Contrib.] set to [100 %]
Parameter [Green Luminance Contrib.] set to [100 %]
Parameter [Red Luminance Contrib.] set to [100 %]
Parameter [Dark Anomaly Headroom] set to [5 %]
Parameter [Dark Anomaly Filter] set to [Off]
--- HDR
Parameter [Small Detail Precision] set to [Max]
Parameter [Channels] set to [Brightness Only]
Parameter [Algorithm] set to [Reveal All]
Parameter [Dark/Bright Response] set to [1.00]
Parameter [Detail Size Range] set to [20 pixels]
Parameter [Strength] set to [1.2]
--- Color
Parameter [Cap Green] set to [To Yellow]
Parameter [Bias Slider Mode] set to [Sliders Reduce Color Bias]
Parameter [Style] set to [Artistic, Detail Aware]
Parameter [LRGB Method Emulation] set to [Straight CIELab Luminance Retention]
Parameter [Dark Saturation] set to [2.50]
Parameter [Bright Saturation] set to [Full]
Parameter [Saturation Amount] set to [275 %]
Parameter [Blue Bias Reduce] set to [1.08]
Parameter [Green Bias Reduce] set to [1.00]
Parameter [Red Bias Reduce] set to [2.23]
Parameter [Mask Fuzz] set to [1.0 pixels]
File saved [/home/geoland/Astrophotography/michele/M31stRGB.tiff].

-----------------------------------------------------------
StarTools 1.4.329
Tue Nov  7 20:02:52 2017
-----------------------------------------------------------
File loaded in LRGB module [/home/geoland/Astrophotography/michele/_20170920_M31_L.tif].
File loaded in LRGB module [/home/geoland/Astrophotography/michele/_20170920_M31_R.tif].
File loaded in LRGB module [/home/geoland/Astrophotography/michele/_20170920_M31_G.tif].
File loaded in LRGB module [/home/geoland/Astrophotography/michele/_20170920_M31_B.tif].
--- LRGB
Parameter [Cap Green] set to [No]
Parameter [Channel Interpolation] set to [On]
Parameter [RGB Blur] set to [1.0 pixels]
Parameter [Blue Ratio] set to [1.00]
Parameter [Green File] set to [1.00]
Parameter [Red Ratio] set to [1.00]
--- Bin
Parameter [Scale] set to [(scale/noise reduction 50.00%)/(400.00%)/(+2.00 bits)]
--- Crop
Parameter [X1] set to [56 pixels]
Parameter [Y1] set to [68 pixels]
Parameter [X2] set to [2546 pixels (-58)]
Parameter [Y2] set to [1698 pixels (-40)]
--- Develop
Parameter [White Calibration] set to [Use Stars]
Parameter [Gamma] set to [1.00]
Parameter [Skyglow] set to [0 %]
Parameter [Digital Development] set to [83.81 %]
Parameter [Blue Luminance Contrib.] set to [100 %]
Parameter [Green Luminance Contrib.] set to [100 %]
Parameter [Red Luminance Contrib.] set to [100 %]
Parameter [Dark Anomaly Headroom] set to [5 %]
Parameter [Dark Anomaly Filter] set to [2.0 pixels]
--- Wipe
Parameter [Mode] set to [Correct Color & Brightness]
Parameter [UNKNOWN] set to [Yes]
Parameter [Precision] set to [256 x 256 pixels]
Parameter [Dark Anomaly Filter] set to [1 pixels]
Parameter [Drop Off Point] set to [100 %]
Parameter [Corner Aggressiveness] set to [100 %]
Parameter [Aggressiveness] set to [75 %]
--- Develop
Parameter [White Calibration] set to [Use Stars]
Parameter [Gamma] set to [1.00]
Parameter [Skyglow] set to [0 %]
Parameter [Digital Development] set to [91.10 %]
Parameter [Blue Luminance Contrib.] set to [100 %]
Parameter [Green Luminance Contrib.] set to [100 %]
Parameter [Red Luminance Contrib.] set to [100 %]
Parameter [Dark Anomaly Headroom] set to [5 %]
Parameter [Dark Anomaly Filter] set to [Off]
--- HDR
Parameter [Small Detail Precision] set to [Max]
Parameter [Channels] set to [Brightness Only]
Parameter [Algorithm] set to [Reveal All]
Parameter [Dark/Bright Response] set to [1.00]
Parameter [Detail Size Range] set to [20 pixels]
Parameter [Strength] set to [1.2]
--- Color
Parameter [Cap Green] set to [To Yellow]
Parameter [Bias Slider Mode] set to [Sliders Reduce Color Bias]
Parameter [Style] set to [Artistic, Detail Aware]
Parameter [LRGB Method Emulation] set to [Straight CIELab Luminance Retention]
Parameter [Dark Saturation] set to [2.50]
Parameter [Bright Saturation] set to [Full]
Parameter [Saturation Amount] set to [400 %]
Parameter [Blue Bias Reduce] set to [1.00]
Parameter [Green Bias Reduce] set to [1.05]
Parameter [Red Bias Reduce] set to [1.52]
Parameter [Mask Fuzz] set to [1.0 pixels]
File saved [/home/geoland/Astrophotography/michele/M31stLRGB400.tiff].
Rowland
 
Posts: 234
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Re: astro pixel processor

Postby Guy » Wed Nov 08, 2017 12:47 pm

Very interesting thread - both the Astro Pixel Processor - and the LRGB processing methods.

The processing steps in Layer Module Use are a variation on the Scott Rosen process and don't include the Rob Gendler 'LLRGB' technique. It may be that this omission has a significant effect on the results.

I think the original Scott Rosen workflow is a big improvement for PhotoShop users as it avoids some of the worst effects that some of the post processing techniques have on colour and noise. StarTools avoids some of these issues by separating L and RGB internally for much of the time tracking is on.

The Rob Gendler technique Multiple Luminance Layering (LLRGB), as far as I understand it, combines the luminance to the RGB twice in different amounts in an attempt to increase the colour without increasing the noise. Does anyone have any experience of using this in StarTools? Might it be a useful approach here?
Guy
 
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