This program is part of Netpbm(1).
pamsharpnessreads a Netpbm image (PNM or PAM) and prints 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.
pamsharpness was added to Netpbm in Release 10.21 (March 2004). Bryan Henderson derived it from the program pnmsharp by B.W. van Schooten and distributed as part of the Photopnmtools package.