.TH pgmenhance 1 "13 January 1989"
.SH NAME
pgmenhance - edge-enhance a portable graymap
.SH SYNOPSIS
pgmenhance [-N] [pgmfile]
.SH DESCRIPTION
Reads a portable graymap as input.
Enhances the edges, and writes a portable graymap as output.
The optional -N argument should be a digit from 1 to 9.
1 is the lowest level of enhancement, 9 is the highest,
The default is 9.
.PP
The edge enhancing technique is taken from Philip R. Thompson's "xim"
program, which in turn took it from section 6 of "Digital Halftones by
Dot Diffusion", D. E. Knuth, ACM Transaction on Graphics Vol. 6, No. 4,
October 1987, which in turn got it from two 1976 papers by J. F. Jarvis
et. al.
.SH "SEE ALSO"
pgm(5), pbm(5)
.SH AUTHOR
Copyright (C) 1989 by Jef Poskanzer.

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted, provided
that the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.  This software is provided "as is" without express or
implied warranty.