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Contrast Limited Adaptive Histogram Equalization
#1
Hello,

There is a page on wikipeda on contrast limited adaptative histogram equalization :
https://en.wikipedia.org/wiki/Adaptive_h...ualization

There is an implementation of contrast limited adaptative histogram equalization on Imagej (Plugins =>Filter => Enhance Local Contrast) with settings for blocksize, histogram bins, max slope. 

Imagemagick also can do contrast limited adaptative histogram equalization,  i have also found it on github :
https://imagemagick.org/script/clahe.php
https://github.com/erich666/GraphicsGems...iv/clahe.c

I don't know equivalent action in Gimp, similar but not the same are tone mapping algorithm like Mantiuk, Reinhard, fattal. Maybe this algorithm can be ported to Gimp as plugin, filter or Gegl action.

On some picture it can be useful to have a better contrast with blocksize to match length of picture and smaller or to get drawing effect with very smaller blocksize and histogram bins.

Here for instance a 387x259 photo with Imagej and different settings :
First row Original - settings blocksize 387, histogram bins 256, max slope 3
Second row 60/60/3 30/30/3


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Contrast Limited Adaptive Histogram Equalization - by remico - 05-16-2019, 09:58 AM

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