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Author Topic: Help with PI please  (Read 4076 times)

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Offline ChrisLX200

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Re: Help with PI please
« Reply #15 on: 11:51:23, 17 December, 2014 »
Phil, my take on it - I went for detail at the expense of retaining some noise :)  I missed some stars embedded within the brighter nebulous areas which should have been masked out, rather careless of me and I didn't notice until afterwards. You'll have to excuse those with ringing. Good data though (this jpg version doesn't do it justice).



ChrisH
Chris Heapy - current: 10-Micron GM2000HPS-II U/P, G11/Gemini, TV NP127is, Altair 8" RC, TV Genesis SDF, TV Pronto, SW Equinox 80ED, 10" LX200, 12" f/5.4 Newt, Vixen 90mm.
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Offline chris.bailey

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Re: Help with PI please
« Reply #16 on: 12:01:38, 17 December, 2014 »
Step 4 - Deconvolution

Now we have a Local Support image and a PSF we can proceed with Deconvolution.

The Global Dark setting can take some degree of experimentation. With Linear Images is normally requires being somewhere around 0.01. It is also sometimes useful to adjust the Wavelet Regularisation controls to avoid Deconvolution increasing background noise. Unfortunately this can take quite a few iterations to get right and there is no magic formula.

40 iterations is normally enough.
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
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Offline chris.bailey

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Re: Help with PI please
« Reply #17 on: 12:06:16, 17 December, 2014 »
Step 5 - TGV De Noise

When applied to Linear Images a good starting point is to turn all the default settings down by one order of magnitude. Using local support is also advised with settings take from the Screen Transfer Function tool as shown. TGVDN is very sensitive to the Edge Protection setting and small changes can have a big impact. At the end of the day it does come down to a compromise between noise and the big brush painted effect that can creep in.

Use of previews to fine tune parameters is advised as running the tool on a full sized image is time consuming.

LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline chris.bailey

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Re: Help with PI please
« Reply #18 on: 12:09:24, 17 December, 2014 »
Step 6 - Masked Stretch

Steps 1 to 6 have been carried out on linear data so it now needs stretching.

As an alternative to the Histogram tool, Masked Stretch achieves a target background level in a number of steps with a luminance mask applied at each. This tends to stop highlights reaching saturation and star bloat.
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline chris.bailey

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Re: Help with PI please
« Reply #19 on: 12:11:50, 17 December, 2014 »
Step 7 - HDR Multiscale Transform

Detail can often be masked within highlights. HDRMT can help drag some of that detail back. Needs to be used with care as it can increase visible noise and/or lead to very false looking images.
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline chris.bailey

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Re: Help with PI please
« Reply #20 on: 12:16:06, 17 December, 2014 »
Step 8 - Local Histogram Equalisation

Acts as an intelligent contrast adding tool. On most images use with a Luminance Mask applied to control it being applied only to the higher signal areas.
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline chris.bailey

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Re: Help with PI please
« Reply #21 on: 12:17:33, 17 December, 2014 »
Step 9 - Curves

At this stage, adjustments using curves are preferable to using the histogram tool (which can increase clipping). A slight brightness increase to taste but with the general aim of trying to avoid the horse head itself being too dark.
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline chris.bailey

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Re: Help with PI please
« Reply #22 on: 12:20:55, 17 December, 2014 »
Step 10 - Morphological Transform (MT) to reduce stars

This image does not really need it but applied with care, this can subtly reduce the impact of dense star fields and tighten up star shapes a little.

The first step is to create and apply a star mask.

Small applications of MT applied in multiple iterations tends to work best
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline chris.bailey

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Re: Help with PI please
« Reply #23 on: 12:21:51, 17 December, 2014 »
End result. Nice data Phil. Add another 6 hours to it and it will be stonking  :laugh:
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline chris.bailey

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Re: Help with PI please
« Reply #24 on: 13:38:40, 17 December, 2014 »
Alternative Step 5 - Linear Noise Reduction with Multiscale Linear Transform

As an alternative linear noise reduction strategy, MLT can be quite effective on Ha images but at the expense of some retained detail I feel.
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline Nomis Elfactem

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Re: Help with PI please
« Reply #25 on: 14:46:50, 17 December, 2014 »
Great work flow Chris.... you should put them in a separate thread and make it a sticky in the processing board mate !!

S.
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Offline Phillyo

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Re: Help with PI please
« Reply #26 on: 16:15:23, 17 December, 2014 »
Brilliant Chris, thank you! I'm going to give this a try tonight and I totally agree with Simon. I think people would find this very useful info.

Phil
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Offline Phillyo

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Re: Help with PI please
« Reply #27 on: 20:07:29, 17 December, 2014 »
For those wanting to give it a try in Photoshop, the following link should take you to the .tif file. Hopefully that'll work :)

Phil

https://www.dropbox.com/s/h7c0wdquwg8859u/light-FILTER_Ha-BINNING_1.tif?dl=0
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Offline Roger B

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Re: Help with PI please
« Reply #28 on: 22:14:48, 17 December, 2014 »
Rog,  have you tried to process an image in PS to compare? I'm still on the fence where PI is concerned and a "blotchy" background is my main concern looking at images from you guys (plus its obvious complexity / time hungry to learn) . To see the same image processed in both would be great to see.

S.

Si,  That's why I moved away from Photoshop as I couldn't really control the noise,  TBH I don't think I could process in PS now anyway lol.   


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Offline harrypage

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Re: Help with PI please
« Reply #29 on: 17:40:19, 28 December, 2014 »
Hi

Bit late , could not resist a quick go :)

Harry

BTW Decon is over rated IMO  :D

 

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