\
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.TH "Ppmrelief User Manual" 0 "02 August 2014" "netpbm documentation"

.SH NAME

ppmrelief - compute a relief of a PPM image

.UN synopsis
.SH SYNOPSIS

\fBppmrelief\fP

[\fIppmfile\fP]

.UN description
.SH DESCRIPTION
.PP
This program is part of
.BR "Netpbm" (1)\c
\&.
.PP
\fBppmrelief\fP reads a PPM image as input, and writes a relief of
that image as a PPM image as output.
.PP
The relief process is described in "Beyond Photography" by
Holzmann, equation 3.19.  It's a sort of edge-detection and is essentially
a convolution with this matrix:

.nf
\f(CW
    |  1  0  0 |
    |  0  0  0 |
    |  0  0 -1 |
\fP
.fi

.UN seealso
.SH SEE ALSO
.BR "pamshadedrelief" (1)\c
\&, 
.BR "pgmbentley" (1)\c
\&, 
.BR "pgmoil" (1)\c
\&, 
.BR "ppm" (5)\c
\&

.UN author
.SH AUTHOR

Copyright (C) 1990 by Wilson Bent (\fIwhb@hoh-2.att.com\fP)
.SH DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML
source.  The master documentation is at
.IP
.B http://netpbm.sourceforge.net/doc/ppmrelief.html
.PP