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PixInsight => Tutorials and Processing Examples => Topic started by: astroedo on 2014 October 17 06:25:47

Title: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: astroedo on 2014 October 17 06:25:47

Hi all,
I've just published on my website a new tutorial on narrowband composition.

It is an adaptation of original J-P Metsavainio technique.

I hope you enjoy it

http://www.radice.biz/articoli/translations/75-narrowband-color-composition-eng

Bye

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: oldwexi on 2014 October 17 09:21:48

Hi Astroedo!

Excellent work!!!!!
You got me also a new idea  about how to create good starmasks for star reduction!
Thanks a lot for making this available.

Gerald

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: astroedo on 2014 October 17 09:26:56

Great! I can't wait for it

I also have an Idea for unconventional starmask building:

I'm experimenting with PixelMath to create a "clipped gradient mask" to use as a Deconvolution support.

I will post as soon as possible

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: kolec on 2014 October 19 03:12:23

Very interesting . Thank for inspiration.

kolec

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: RickS on 2014 October 19 04:14:31

Thanks from me too, Edoardo.  That was an interesting read.  The last couple of NB images I processed I did something quite similar except that I didn't remove the stars completely - I just reduced the size of the OIII and SII stars significantly before I did the combine to generate the colour component of the image.

Cheers,
Rick.

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: jkmorse on 2014 October 20 08:57:02

Edoardo,

Thanks for posting!  Fascinating read.  Been struggling with some really good NB data of NGC281 and looking forward to trying your technique.

Best,

Jim 

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: Geoff on 2014 October 21 01:07:14

Very nice Edoardo.  The main disadvantage is that you lose all colour in the stars.  Do you see any way around this?
Geoff

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: Geoff on 2014 October 21 01:37:53

I tried this process to get rid of the stars on an image, just to see how it went.  It seems that the star mask is critical.  When I applied MMT after applying the star mask to the image, it got rid of most of the stars, but not the very little ones nor the very bright ones. Some more tweaking got rid of a few more of the bright stars but still not the little ones--I suppose I have to experiment a bit more (a la Harry).
Geoff

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: astroedo on 2014 October 21 10:17:49

Thank you Geoff!

Yes the star mask is crucial, sometime I use two different settings to get all the stars, and I use a range mask enlarged with morphological transformations for the big saturated stars.

Then I merge the different masks using the max() operator in PixelMath.

I've Just downloaded Tone Mapping V2 by Metsavainio where it explains how to recover stars colors and I'm working to integrate it in the normal workflow in PI.

Unfortunately I don't have so much time as I would like to make tests and write tutorials...  :-[

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: jkmorse on 2014 October 21 11:06:57

Edoardo,

A quick question about the boosting factor formula you present for Hubble Palette color balance.  What is the point of the second half of the red and blue formulae ("-(OFFSET*(SII[OIII]Boost-1))").  Unless I am missing something, the deduct, in the Sii case, takes the boost of 7 down to 6.997 and in the case of Oiii, reduces the boost from 4 to 3.9985.   

Do those miniscule reductions really add anything to the result, can they just be ignored, or am I missing something?

Thanks,

Jim

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: astroedo on 2014 October 21 11:23:11

Its goal is to keep the background with a neutral color.
without this correction you would have a strongly colored background because its value would be boosted.

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: jkmorse on 2014 October 22 08:09:02

Thanks for the clarification.

Best,

Jim

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: Buzz on 2014 December 19 06:23:50

The tutorial is great, many thanks - I'm trying to achieve the blue and gold motif (traditionally by using selective color adjustments in Photoshop- removing cyan from green for instance). In your tutorial, even with scaling, I'm getting a very green result from the dominant Ha. Are you using some wonderful curves transformation to achieve the color balance in the last two steps?

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: astroedo on 2014 December 19 10:12:23

Hi, I sometimes use InterChannelCurves Module using Green (or another color channel) as Both reference and target channel.

InterChannelCurves is an optional module that you can downolad for free from Carlos Milovic website http://www.astrophoto.cl/Research.html

you can also find information here.

http://pixinsight.com/forum/index.php?topic=2275.0

I hope this helps  ;)

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: troypiggo on 2014 December 19 11:26:05

Have you tried Rick's new script?
http://pixinsight.com/forum/index.php?topic=7751.0

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: Buzz on 2014 December 20 06:38:22

Thanks all,  I will try the script, looks perfect. I was scratching my head to think how I could select color ranges. My Xmas reading is a 500 page book in JScript. I used to program decades ago and I seriously need to re-aquaint myself and similarly share ideas and stuff

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: RickS on 2014 December 20 12:46:48

I still have to incorporate the feedback from Juan and others into ColorMask.  I hope to do that while things are quiet at work over the holidays.  I think it's still quite usable in its current form, of course, and I have been using it for processing some of my own images.  Any further feedback would be appreciated...

Cheers,
Rick.

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: troypiggo on 2014 December 20 13:21:48

Do I get a commission for pointing people to your script? :)

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: cfranks on 2014 December 20 16:47:38

Yes.  You get to use it one more time, for free!

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: RickS on 2014 December 20 17:28:30

You can have 20% of the gross revenue, Troy  :D

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: troypiggo on 2014 December 20 19:18:04

Awesome :)

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: Buzz on 2014 December 23 02:33:14

Thanks guys - the colormask script is brilliant and in fact I'm going to study it in detail as a means to understand how to write my own. I'm going to follow up on the interchannel curves module too during the holidays.

clear skies

Title: Re: Narrowband color composition using J-P Metsavainio Tone Map technique in PI
Post by: Buzz on 2015 January 01 04:34:39

Happy New Year all -  I managed to convert  image 1 to image 2 with the script. If I manage to generate something equally as useful in the future I will share it with the community too. I used to program twenty five years ago but the gears need a little lubrication. I bought myself a book in vbscript over the holiday and completely humbled myself!

before  http://www.digitalastrophotography.co.uk/Astrophotography/Images.html#7 (http://www.digitalastrophotography.co.uk/Astrophotography/Images.html#7)
after  http://www.digitalastrophotography.co.uk/Astrophotography/Images.html#8 (http://www.digitalastrophotography.co.uk/Astrophotography/Images.html#8)