Author Topic: HDRMT  (Read 310 times)

Offline tdgm

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HDRMT
« on: 2019 January 05 21:50:26 »
Hello Anyone

I am trying to figure out how to do HDRMT on an image with a star mask covering all the stars and on the large stars I continue to start to get a doughnut. Star core starts to become darker at 6 layers and gets worse as I lower the layers. Larger # layers no star core problem but also no enhancement of the image (visible)

Any help would be appreciate


Steve

Offline RickS

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Re: HDRMT
« Reply #1 on: 2019 January 05 22:58:33 »
I normally make a clipped lum mask, remove all the stars (something like PixelMath "iif(star_mask>0.1,0,$T)") and then blur a little with convolution.  I use that to mask the image when applying HDRMT.

Cheers,
Rick.

Offline tdgm

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Re: HDRMT
« Reply #2 on: 2019 January 05 23:16:37 »
Hello Rick

Did not help with preventing the doughnut on larger stars.

Steve

Offline RickS

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Re: HDRMT
« Reply #3 on: 2019 January 06 00:45:05 »
Steve,

You have the option to increase the coverage of the stars (reduce the "0.1" factor in the PixelMath expression) or use MorphologicalTransformation Dilation to increase the size of the stars in your star mask.  If you have a troublesome star then masking it out is probably the best solution.  There are many ways to get there...

Cheers,
Rick.

Offline tdgm

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Re: HDRMT
« Reply #4 on: 2019 January 06 22:44:55 »
Hello Rick


I have tried increasing size of stars in the star mask and even when I can see the star is completely covered by the star mask on medium/large stars after HDRMT the core gets darker and gives a doughnut appearance.

Well, I might just have to use 6 layers and live with that for HDRMT


Steve

Offline RickS

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Re: HDRMT
« Reply #5 on: 2019 January 07 00:43:18 »
Hi Steve,

If the core of the star is changing then the mask isn't protecting it properly.  Maybe the mask isn't strong enough or you need to invert it?

Cheers,
Rick.

Offline tdgm

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Re: HDRMT
« Reply #6 on: 2019 January 08 13:57:45 »
Thanks Rick


I did try to increase strength of the mask and helped a little but still unable to decrease layers in HDRMT with our showing that doughnut. BUt it did help a little. Maybe stopp looking a a magnification of 5:1 in PixInsight would help. Problem is only visible when magnified.


Steve

Offline dhb2206

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Re: HDRMT
« Reply #7 on: 2019 February 11 09:56:52 »
This might be stating the bleeding obvious, but you have checked the star in question is in the star mask? Sometimes the big fellas get left out.

Cheers,

David