pamditherbw
Apply dithering to a greyscale image, i.e. turn it into a pattern of black and white pixels that look the same as the original greyscale.
See also: pbmreduce.
More information: https://netpbm.sourceforge.net/doc/pamditherbw.html.
- Read a PGM image, apply dithering and save it to a file:
ppmditherbw path/to/image.pgm > path/to/file.pgm
- Use the specified quantization method:
ppmditherbw -floyd|fs|atkinson|threshold|hilbert|… path/to/image.pgm > path/to/file.pgm
- Use the atkinson quantization method and the specified seed for a pseudo-random number generator:
ppmditherbw -atkinson -randomseed 1337 path/to/image.pgm > path/to/file.pgm
- Specify the thresholding value for quantization methods that perform some sort of thresholding:
ppmditherbw -fs|atkinson|thresholding -value 0.3 path/to/image.pgm > path/to/file.pgm