Re: sparkle identification

Posted by Herbie-6 on Nov 18, 2011; 5:56pm
URL: http://imagej.273.s1.nabble.com/sparkle-identification-tp3682531p3682532.html

>Hi all,
>I have an image with sparkles on a surface
>( you can see this image on
>http://www.fotos-hochladen.net/view/imgixh0pb9jtu.jpg)
>-the black dots in the image, not the
>black big area in the middle
>
>my probelm is to find a solution to find
>(quite) all of the black "dots"
>
>I tried some brightness/contrast sepearion
>did some band pass filtering and find maxima
>but nothing worked well
>
>mybe you have some hints ?
>
>thank you very mutch !

Dear Heins Spilker,

although the following may need some parameter tweaking for different
images of this kind you may try this two-step procedure:

1
Process >> FFT >> BandpassFilter
with large=30; small=5; AutoScale; perhaps Saturate;

2
Process >> Find Maxima
NoiseTolerance=20; OutputType=MaxWithTol; ExcludeEdgeMax; LightBackgr;


HTH

                   Herbie

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