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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML><HEAD><TITLE>Ppmrelief User Manual</TITLE></HEAD>
<BODY>
<H1>ppmrelief</H1>
Updated: 02 August 2014
<BR>
<A HREF="#index">Table Of Contents</A>

<H2>NAME</H2>

ppmrelief - compute a relief of a PPM image

<H2 id="synopsis">SYNOPSIS</H2>

<B>ppmrelief</B>

[<I>ppmfile</I>]

<H2 id="description">DESCRIPTION</H2>

<p>This program is part of <a href="index.html">Netpbm</a>.

<p><b>ppmrelief</b> reads a PPM image as input, and writes a relief of
that image as a PPM image as output.

<P>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:

<pre>
<tt>
    |  1  0  0 |
    |  0  0  0 |
    |  0  0 -1 |
</tt>
</pre>

<H2 id="seealso">SEE ALSO</H2>

<A HREF="pamshadedrelief.html">pamshadedrelief</A>, 
<A HREF="pgmbentley.html">pgmbentley</A>, 
<A HREF="pgmoil.html">pgmoil</A>, 
<A HREF="ppm.html">ppm</A>

<H2 id="author">AUTHOR</H2>

Copyright (C) 1990 by Wilson Bent (<A
HREF="mailto:whb@hoh-2.att.com">whb@hoh-2.att.com</A>)

<HR>
<H2 id="index">Table Of Contents</H2>
<UL>
<LI><A HREF="#synopsis">SYNOPSIS</A>
<LI><A HREF="#description">DESCRIPTION</A>
<LI><A HREF="#seealso">SEE ALSO</A>
<LI><A HREF="#author">AUTHOR</A>
</UL>
</BODY>
</HTML>