Equalize Local Histogram as a CLI command?

Software G'MIC
1

While trying to help some one with extracting vessel shape from photographs of retinal scans (Not surprisingly, it’s a difficult problem (I failed to find a solution)) , I find that Equalize Local Histogram command is not available as a non-GUI command. Closest is sharpen_alpha.

There’s also this technique here I found while trying to help him on that - Electronics | Free Full-Text | An Automated Image Segmentation and Useful Feature Extraction Algorithm for Retinal Blood Vessels in Fundus Images .

2

The number of papers for this is legion. Have you tried Canny? Often, it is that with normalization and/or CLAHE beforehand and then some cleanup afterwards.

3

A good idea to keep in mind : Command apply_tiles applies a G’MIC command “locally” on the image, and you can even specify an overlap size to keep things smooth.
For histogram equalization :

$ gmic sp colorful +apply_tiles \"equalize 256\",32,32,1,50%,50%,0,1

foo
foo984×520 146 KB

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4

Yes, that is the one (not CLAHE but applicable). I believe @garagecoder or @Iain had something to that effect as well.

5

Possibly “local f-mean” is quite similar output, but not using histograms. As you say, there are countless things on this topic.
gmic sp colorful gcd_fx_local_fmean 1,0,2,5
localfmean

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