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Star reduction.

Melvin Atkins
in PixInsight
Hi I’ve been watching both Lukomatico and Bill Blanchen videos regarding star reduction and I see in the scrip section under utilities is a link for star reduction. Are there any videos about this script? I can see no difference when I select strong etc, there are three selections on the drop down menu. Anyone advise please.

Comments

  • BlockHeadBlockHead
    HI Melvin,

    I cover star reduction in a number of places. In addition, (and you did not mention), I came up with an independent way to do star reduction as well and a script we made for it. 

    The Bill Blanshan method is not really star reduction per se. It is a modification of the MTF (brightness) of the image on a star layer before screening back into a starless image. For many people that accomplishes the intended goal. My method, which I find it is not really necessary anymore- is completely different and it is an improvement on erosion techniques (the only kinds available at the time I made the method) by using pixel substitution that leverages the power of star removal.

    FInally in many other videos I demostrate a method using BXT in starry fields. 

    So I have many videos on this topic. Did you try to search my site?

    Here is an example section for the Blanshan MTF adjustment:

    Here is the example using the BXT method I developed:
    and another one 


    (These are the historical ones)

    This is the script that was created to assist in my pixel substittion method:

    There are more as well.
    I hope you agree I touched on this subject.
    -the Blockhead
  • Mike Cranfield
    It is not quite true to say: "The Bill Blanshan method is not really star reduction per se. It is a modification of the MTF (brightness) of the image on a star layer before screening back into a starless image."

    The script that Bill and I produced, which I am guessing is the subject of the videos that Melvin has been watching, offers four different methods of star reduction. The first, the" Transfer Method", is as Adam suggests - ie essentially a reverse stretch on the stars - but the other three each use different algorithms. 

    The script has documentation that can be accessed using the documentation button at the bottom of the script. The documentation gives detail on the maths behind each method.

    The effect of changing the parameters can be quite subtle - if you have difficulty seeing it on the entire image then try zooming in. Different methods work better on different images - my personal "Go-To" tends to be the Lightness method.
  • BlockHeadBlockHead
    Yes sorry, I should be precise. The Blanshan method I cover in my content. I didn't catch the reference to the other methods of the script since I haven't pursued these other ways.

    -the Blockhead
  • Melvin Atkins
    Hi and thanks for your replies.
    The reason I wanted to look at date reduction is because someone sent to me an imaging which is of a Nebula and, in my opinion, the stars are taking over the image, sorry I’m not able to show you that image I don’t know how. Anyway thanks again, sorry it’s taken a while to respond but I wanted to watch all the videos you linked to.
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