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| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2006-12-25 03:06:05 +0000 |
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| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2006-12-25 03:06:05 +0000 |
| commit | 1017cbebe5d5edd859e0fddad0a8600f509f4821 (patch) | |
| tree | 78bdf336648566f7a7d55f42837357dea3dd674c /pgmmedian.html | |
| parent | 16f2ac126651015a376eba864a3a35f738b0b25a (diff) | |
| download | netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.tar.gz netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.tar.xz netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.zip | |
Place user guide into Subversion repository
git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@181 9d0c8265-081b-0410-96cb-a4ca84ce46f8
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1 files changed, 135 insertions, 0 deletions
diff --git a/pgmmedian.html b/pgmmedian.html new file mode 100644 index 00000000..8a2a1a1f --- /dev/null +++ b/pgmmedian.html @@ -0,0 +1,135 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<HTML><HEAD><TITLE>Pgmmedian User Manual</TITLE></HEAD> +<BODY> +<H1>pgmmedian</H1> +Updated: 28 August 2005 +<p> + +<A HREF="#index">Table Of Contents</A> + +<H2>NAME</H2> + +pgmmedian - apply a median filter to a PGM file + +<H2 id="synopsis">SYNOPSIS</H2> + +<B>pgmmedian</B> + +[<b>-width=</b><i>n</i>] + +[<b>-height=</b><i>n</i>] + +[<B>-type=</B><I>median_type</I>] + +[<B>-cutoff=</B><I>int</I>] + +[<I>pnmfile</I>] + + +<P>Minimum unique abbreviation of option is acceptable. You may use double +hyphens instead of single hyphen to denote options. You may use white +space in place of the equals sign to separate an option name from its value. + +<H2 id="description">DESCRIPTION</H2> + +<p>This program is part of <a href="index.html">Netpbm</a>. + +<p><b>pgmmedian</b> applies a median filter to a PGM image, using either +the histogram sort of select kth value method to determine the median. + +<p>See the <b>-type</b> and <b>-cutoff</b> options for information on +how <b>pgmmedian</b> chooses between the two methods. + +<H2 id="options">OPTIONS</H2> + +<DL COMPACT> +<DT><B>-cutoff</b> <i>int</i> + +<DD>This option provides the cutoff value that <b>pgmmedian</b> uses +to decide between using the histogram sort or select kth value method +to find the median. + +If (<i>maxval</i> / ((<i>width</i> * <i>height</i>) - 1)), where +<i>maxval</i> is the maxval of the image and <i>width</i> and +<i>height</i> are the dimensions of the mask, is less than the cutoff +value, <b>pgmmedian</b> uses histogram sort. Otherwise, it uses kth +value. + +<p>If expression is less than the cutoff, <b>pgmmedian</b> uses the +histogram sort. Otherwise it uses the select kth value method. + +<p>This option has no effect if you specify <b>-type</b>. + +<p>The default is 250 + +<DT><B>-width=</b><i>n</i> + +<DD>Width of the median mask to apply. + +<p>Default is 3. + +<DT><B>-height=</b><i>n</i> + +<DD>Height of the median mask to apply. + +<p>Default is 3. + +<DT><B>-type</b> <i>median_type</i> + +<DD>This option selects which method to use to find median regardless +of cutoff value. Choices are <b>histogram_sort</b> and <b>select</b>. + +<p>By default, <b>pgmmedian</b> decides which method to use as described +under the <b>-cutoff</b> option. + +</DL> + +<H2 id="references">REFERENCES</H2> + +<ul> + +<li>"Collected Algorithms from ACM" Volume II, Algorithm 489 +by Robert W. Floyd + +<li>"A Fast Two-Dimensional Median Filtering Algorithm" in +"IEEE Transactions on Acoustics, Speech, and Signal +Processing" Vol. ASSP-27, No. 1, February 1979 + +<li>"Digital Image Processing Algorithms" by Ioannis +Pitas, Prentice Hall, 1993 ISBN 0-13-145814-0 + +</ul> + + +<H2 id="seealso">SEE ALSO</H2> + +<A HREF="pgmnoise.html">pgmnoise</A>, +<A HREF="pamaddnoise.html">pamaddnoise</A>, +<A HREF="pgm.html">pgm</A> + +<h2 id="history">HISTORY</h2> + +<P><b>pgmmedian</b> was added to Netpbm in Version 10.29 (August 2005). +It had been distributed by Mike Burns via his own web site before that +(and continued to be so). + + +<H2 id="author">AUTHOR</H2> + +Copyright (C) 1996 by Mike Burns <<A +HREF="mailto:burns@cac.psu.edu">burns@cac.psu.edu</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="#options">OPTIONS</A> +<LI><A HREF="#references">REFERENCES</A> +<LI><A HREF="#seealso">SEE ALSO</A> +<LI><A HREF="#history">HISTORY</A> +<LI><A HREF="#author">AUTHOR</A> +</UL> + +</BODY> +</HTML> |