pgmedge

 

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 pgmedge(1)                                             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 operators at 90
        degrees to each other.   For  more  details  see  "Digital
        Image Processing" by Gonzalez and Wintz, chapter 7.
 
SEE ALSO
        pgmenhance(1), pgmtopbm(1), pgm(5), pbm(5)
 
AUTHOR
        Copyright (C) 1991 by Jef Poskanzer.
 
 
 
                          04 February 1990              pgmedge(1)

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