On Apache
Under GNU General Public License
2025-01-14 23:31 @3.15.151.109 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
pgmedge(1) General Commands Manual pgmedge(1)
NAME
pgmedge - edge-detect a portable graymap
SYNOPSIS
pgmedge [pgmfile]
DESCRIPTION
Reads a portable graymap as input. Outlines the edges, and writes a portable graymap as
output. Piping the result through pgmtopbm -threshold and playing with the threshold
value will give a bitmap of the edges.
The edge detection technique used is to take the Pythagorean sum of two Sobel gradient op-
erators at 90 degrees to each other. For more details see "Digital Image Processing" by
Gonzalez and Wintz, chapter 7.
The maxval of the output is the same as the maxval of the input The effect is better with
larger maxvals, so you may want to increase the maxval of the input by running it through
pnmdepth first.
SEE ALSO
pgmenhance(1), pgmtopbm(1), pnmdepth(1), pgm(5), pbm(5)
AUTHOR
Copyright (C) 1991 by Jef Poskanzer.
04 February 1990 pgmedge(1)
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
2025-01-14 23:31 @3.15.151.109 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)