pgmedge

NAME
SYNOPSIS
DESCRIPTION
SEE ALSO
AUTHOR

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.