pamedge

   Updated: 11 January 2003
   Table Of Contents

NAME

   pamedge - edge-detect an image

SYNOPSIS

   pamedge [imagefile]

DESCRIPTION

   This program is part of Netpbm.

   pamedgereads 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 maxval of
   the output is at least 255 and if the input is PBM, the output
is PGM.

   You	can pipe the result through pgmtopbm -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 de-
tails see
   "Digital Image Processing" by Gonzalez and Wintz, chapter 7.

   The maxval of the output is the same as the maxval of the  in-
put 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, pgmtopbm, pnmdepth, pammasksharpen,  pamsharpness,
pamsharpmap,
   pam, pnm

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.
     _________________________________________________________________



Table Of Contents

     * NAME
     * SYNOPSIS
     * DESCRIPTION
     * SEE ALSO
     * HISTORY
     * AUTHOR

UNIX/Linux commands referenced on this page:

1. as
2. at
3. pgmtopbm
4. sum
5. more
6. pnmdepth
7. pgmenhance
8. pammasksharpen
9. pgmedge
10. which