pgmdiff(1)

NAME

pgmdiff - compare two greyscale images producing a different image

SYNOPSIS

pgmdiff <file1> <file2> <outfile> [magnify]

DESCRIPTION

pgmdiff subtracts from the image file1 a second image file2 to produce a difference image outfile. Naturally, it does make a difference which of the two input files is specified first in the command line.

Optionally, a factor magnify can be specified to multiply the result with. This can be useful to enhance the visibility of the found differences.

If the subtraction leads to greyscale values less than 0 or greater than 255, they will be shifted and rescaled to fit into the interval 0..255.

NOTES

The pgmdiff utility is part of the Wavelet class library package. The version number refers to the whole package rather than to the utility.

Apart from PGM, pgmdiff may, if enabled, also be able to read and write PFI files. However using different file formats in the same command line may not be a good idea.

BUGS

None known yet.

COPYRIGHT
Copyright (C) 2001-2003 Herbert

pgmdiff is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version.

pgmdiff is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

AUTHOR
Herbert Martin Dietze <herbert@spamcop.net>