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 maxval 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.

OPTIONS

       There are no command line options defined specifically for pamedge, but it recognizes the options  common
       to all programs based on libnetpbm (See  Common Options .)

SEE ALSO

       pgmenhance(1),  pamditherbw(1),  pamdepth(1), pammasksharpen(1), pamsharpness(1), pamsharpmap(1), pam(1),
       pnm(1)

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.

DOCUMENT SOURCE

       This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The  master  documentation
       is at

              http://netpbm.sourceforge.net/doc/pamedge.html

netpbm documentation                             11 January 2003                          Pamedge User Manual(1)