pnmsmooth – smooth out an image
pnmsmooth [-size width height] [-dump dumpfile] [pnmfile]
Smooths out an image by replacing each pixel with the average of its
width X height neighbors. It is implemented as a C progam that gener‐
ates a PGM convolution matrix and then invokes pnmconvol.
-size width height
Specifies the size of the convolution matrix. Default size is a
3×3 matrix. Width and height sizes must be odd. Maximum size
of convolution matrix is limited by the maximum value for a
pixel such that (width * height * 2) must not exceed the maximum
Generates and saves the convolution file only. Use of this
option does not invoke pnmconvol.
Copyright (C) 1989, 1991 by Jef Poskanzer.
Converted from script to C program December 1994 by Mike Burns
4 December 1994 pnmsmooth