x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
Pamedge User Manual(0) Pamedge User Manual(0)
NAME
pamedge - edge-detect an image
SYNOPSIS
pamedge [imagefile]
DESCRIPTION
This program is part of Netpbm(1)
pamedge reads a Netpbm image (PNM or PAM) and produces an image that
outlines the edges.
The output image is of the same type as the input, except that the max-
val of the output is at least 255 and if the input is PBM, the output
is PGM.
You can pipe the result through pamditherbw -threshold and play with
the threshold value to get a PBM (bilevel image) 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.
The maxval of the output is the same as the maxval of the input, except
at least 255. The effect is better with larger maxvals, so you may
want to increase the maxval of the input by running it through pamdepth
first.
SEE ALSO
pgmenhance(1) , pamditherbw(1) , pamdepth(1) , pammasksharpen(1) ,
pamsharpness(1) , pamsharpmap(1) , pam(5) , pnm(5)
HISTORY
pamedge was added to Netpbm in Release 10.14 (March 2003). It replaced
pgmedge, which was the same thing, but worked only on PGM and PBM
images.
AUTHOR
Copyright (C) 1991 by Jef Poskanzer. Adapted to pnmedge Peter
Kichgessner in 1995, and then to pamedge by Bryan Henderson in 2003.
netpbm documentation 11 January 2003 Pamedge User Manual(0)
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