This program is part of Netpbm(1).
pamsharpness reads a Netpbm image (PNM or PAM) and prints a message to Standard Output giving a number that tells how sharp it is.
Sharpness is a measure of how suddenly (in space) colors change in the image. pamsharpness computes the sharpness of the image as the average difference in intensity between each pixel and its 8 surrounding pixels, in each of the color components (R, G, B).
pamsharpness does not include the edges of the image, where there are not 8 pixels surrounding a pixel, in its computation.
pamsharpness assumes that the image is a PNM or PNM equivalent PAM. If it isn't, the results are not necessarily meaningful.