Author Topic: New Method for Star De-Emphasis by Adam Block  (Read 601 times)

Offline ngc1535

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New Method for Star De-Emphasis by Adam Block
« on: 2019 April 21 22:51:28 »
Hi all,

Recently I published my method for de-emphasizing stars. This method does not use an erosion filter and so avoids the pitfalls/artifacts of the method.
I demonstrated the technique during my guest appearance on the Astro Imaging Channel last Sunday April 20th 2019.
In addition, because it is popular in some circles, I also went through the exercise of creating a written version of the technique (though I still think the video methods are always best).

Please visit the free material section of my website here:

https://www.adamblockstudios.com/categories/Free_Content

You will find both the embedded YouTube video as well as a link to the written version (below):

https://www.adamblockstudios.com/articles/star_demph

On a meta-note concerning PI- I showed this technique during my invited talk and workshop at NEAIC a few weeks ago. It was titled "Innovations in PixInsight" and the idea behind the talk was to highlight not only what PI does- but what it can be made to do. PixInsight by design permits a user to develop methods and tools that may not exist due to its open ended implementation. Although I have seen many talks on how to use PixInsight; but I was striving to show yet a greater level of abstraction- one that is very powerful as I hope my innovation above shows.

Even if the technique isn't your cup of tea- you might find the sub-techniques I used of interest in and of themselves. Although teaching PI is part of my "business"- it is also important to give back to a community that has always been extremely supportive of my efforts.

Someone who watched the video published their results (and was happy!) on the Cloudy Nights Forum.
https://www.cloudynights.com/topic/658570-same-data-different-processing-the-wizard-nebula/#entry9309605

It is a subtle processing effect... especially at this scale- but note how the nebulosity is easier to see with the de-emphasis of the stars in my example image**,



Sincerely,
Adam Block

** This image example was kindly provided to me by Terry Robison. It is always best to demonstrate your techniques on other people's images.

« Last Edit: 2019 April 22 07:12:14 by ngc1535 »

Offline Juan Conejero

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Re: New Method for Star De-Emphasis by Adam Block
« Reply #1 on: 2019 April 22 02:08:43 »
Hi Adam,

Congratulations on a nice and clever method of star reduction. I like the way you apply multiscale analysis. A good example of the outstanding usefulness of these algorithms, especially MMT to isolate structures. The use of artificial noise to generate seamless transitions is also an interesting algorithmic idea. I am implementing a related technique (randomization) for seamless mosaic generation. An effective and highly controllable technique, very recommendable.
Juan Conejero
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http://pixinsight.com/

Offline llpastro

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Re: New Method for Star De-Emphasis by Adam Block
« Reply #2 on: 2019 April 23 13:25:02 »
Adam, I tried to copy your instructions from your link to the article but it appears your website is copy protected.  Any way to print the instructions for use offline?

Larry
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Offline ngc1535

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Re: New Method for Star De-Emphasis by Adam Block
« Reply #3 on: 2019 April 23 16:35:51 »
Adam, I tried to copy your instructions from your link to the article but it appears your website is copy protected.  Any way to print the instructions for use offline?

Larry

Hi Larry,

Right click is disabled on my site (which I assume is how you tried to copy the information). However, if you use your keyboard to get the contents into your clipboard, it will work.
In Windows CRTL+C . I was able to copy and paste into a Word document OK (it copied everything... font, background, pictures... lol).
-adam

Offline msmythers

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Re: New Method for Star De-Emphasis by Adam Block
« Reply #4 on: 2019 April 23 16:36:21 »
Larry

I right clicked on the side of the article and was able to save it as a PDF. I'm using Opera as my browser. I just checked and I was able to view the saved pdf in my other browsers.



Mike

Offline llpastro

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Re: New Method for Star De-Emphasis by Adam Block
« Reply #5 on: 2019 April 24 07:32:23 »
Thanks Mike, that worked.
Larry
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Offline STEVE333

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Re: New Method for Star De-Emphasis by Adam Block
« Reply #6 on: 2019 April 24 15:15:40 »
Very nice technique Adam - You are a creative wizard.

I gave it a go on an image of the East/West Veil. I didn't fully process the image. Just wanted to see how your technique worked. I processed the image up through Linear processing with a light MLT noise reduction. I then combined a HT stretch with an Arcsinh stretch (50/50) and that is all the processing that was done.

Your technique reduced the brightness of the smaller stars beautifully. I need to go back and "mask out" the brighter stars to prevent artifacts (any suggestions gratefully suggested). A side-by-side comparison of a portion of the image is shown in the attachment. The image on the left is from the original image and the image on the right shows the results of using your technique (only one iteration).

I had tried another technique for removing stars. It removed the stars beautifully, but, it also blurred out some of the nebula details. Your technique left all the nebula details "untouched".

Well done, and, thanks for sharing.

Steve
WO Star71 ii
Canon DSLR (modified)
http://www.SteveKing.Pictures/

Offline STEVE333

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Re: New Method for Star De-Emphasis by Adam Block
« Reply #7 on: 2019 April 24 19:46:06 »
Just FYI - I subtracted a modified RangeSelection mask from the Halos mask to protect the larger stars. That removed most of the artifacts from the "dimmed stars" result.

Really like your process.

Thanks again.

Steve
WO Star71 ii
Canon DSLR (modified)
http://www.SteveKing.Pictures/

Offline Solidarity

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Re: New Method for Star De-Emphasis by Adam Block
« Reply #8 on: 2019 May 22 02:22:36 »
Hello Adam,

very good Method to dim the stars.

In my Image the effect is very strong and my question is how to have smaller amounts of dimming. Is it caused by a "wrong" mask?

In the ataatched image of M42 with DSLR you will see the effect on the image which is not yet processed to the end.

Greetings from germany

Karsten