On Apache
Under GNU General Public License
2024-04-27 00:39 @3.144.238.20 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
Pbmtopgm User Manual(0) Pbmtopgm User Manual(0)
NAME
pbmtopgm - convert PBM image to PGM by averaging areas
SYNOPSIS
pbmtopgm width height [pbmfile]
DESCRIPTION
This program is part of Netpbm(1).
pbmtopgm reads a PBM image as input. It outputs a PGM image in which each pixel's gray
level is the average of the surrounding black and white input pixels. The surrounding
area is a rectangle of width by height pixels.
In other words, this is a convolution. pbmtopgm is similar to a special case of pnmcon-
vol.
You may need a pnmsmooth step after pbmtopgm.
pbmtopgm has the effect of anti-aliasing bitmaps which contain distinct line features.
pbmtopgm works best with odd sample width and heights.
You don't need pbmtopgm just to use a PGM program on a PBM image. Any PGM program (assum-
ing it uses the Netpbm libraries to read the PGM input) takes PBM input as if it were PGM,
with only the minimum and maximum gray levels. So unless your convolution rectangle is
bigger than one pixel, you're not gaining anything with a pbmtopgm step.
The opposite transformation (which would turn a PGM into a PBM) is dithering. See
pamditherbw.
SEE ALSO
pamditherbw(1), pnmconvol(1), pbm(1), pgm(1)
AUTHOR
Copyright (C) 1990 by Angus Duggan.
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.
DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML source. The master
documentation is at
http://netpbm.sourceforge.net/doc/pbmtopgm.html
netpbm documentation 05 Feb 2003 Pbmtopgm User Manual(0)
Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2024-04-27 00:39 @3.144.238.20 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)