.\"
.\" cmp_pgm.1 - the *roff document processor man page source
.\"
.TH cmp_pgm 1 "98/07/08" "Watermarking, Version 1.0"
.SH NAME
cmp_pgm \- a program to create the difference image of two PGM images
.SH SYNOPSIS
.B cmp_pgm
[
.B \-h
]
[
.BI \-m \ number
]
[
.BI \-o \ ofile
]
.BI \-i \ ifile
.I file
.SH DESCRIPTION
.B cmp_pgm
is a program to create the difference image of two PGM (portable graymap)
grayscale images. To compare PPM (portable pixmap) RGB color images, use the
.B cmp_ppm
program.
.PP
If
.I file
or
.I ofile
is not specified, then standard input or standard output is
used.
.PP
.SH OPTIONS
.TP
.B \-h
Print a help message.
.TP
.BI \-i \ ifile
The original image. Mandatory.
.TP
.BI \-m \ number
Multiplication factor to magnify differences between the to
original and input image.
Default value: 16.
.TP
.BI \-o \ ofile
Output image file to contain the difference image in PGM format.
.TP
.I file
Input image that is compared against
.I ifile.
Default: standard input.
.SH OUTPUT
The difference image in PGM format is written to standard output or,
optionally, to
.I ofile.
.SH AUTHOR
Peter Meerwald.
Email bug reports to pmeerw@cosy.sbg.ac.at.
.SH AVAILABILITY
The most recent released version of
.B cmp_pgm
is always available
at http://www.cosy.sbg.ac.at/~pmeerw/Watermarking or via anonymous ftp from ftp.cosy.sbg.ac.at in the
directory /pub/people/pmeerw/Watermarking.
.SH "SEE ALSO"
.B cmp_ppm
(1)