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pgmedge - edge-detect a portable graymap
pgmedge [pgmfile]
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.
pgmenhance(1)
, pgmtopbm(1)
, pgm(5)
,
pbm(5)
Copyright (C) 1991 by Jef Poskanzer.
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