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 ⟨index.html#commonoptions⟩ .)

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