ppmdist

Calculate distance transform

$ ppmdist [input.ppm] > [output.pgm]

ppmdist [options] [file]

ppmdist calculates distance from each pixel to a target color, producing a grayscale distance map. Useful for edge detection and segmentation. Part of Netpbm toolkit.

-intensity

Use intensity-based distance.

ppmcolormask(1), pnmedge(1)