pnmhisteq
Histogram-equalize a PNM image.
TLDR
Increase the contrast of a PNM image using histogram equalization
$ pnmhisteq [path/to/input.pnm] > [path/to/output.pnm]
Only modify grey pixels
$ pnmhisteq -grey [path/to/input.pnm] > [path/to/output.pnm]
Do not include black or white pixels in the histogram equalization
$ pnmhisteq -no[black|white] [path/to/input.pnm] > [path/to/output.pnm]
