man > pamedge(1)

Pamedge User Manual(1)                 General Commands Manual                Pamedge User Manual(1)

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 opera‐
       tors at 90 degrees to each other.  For more details see "Digital Image Processing" by  Gonza‐
       lez 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 op‐
       tions 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)