pgmdenoise(1)

NAME

pgmdenoise - denoises a greyscale image

SYNOPSIS

pgmdenoise <infile> <outfile> <from> <to> [<alpha> [<filter> [<sfunction> [rfunction [<areas>]]]]]

DESCRIPTION

pgmdenoise opens infile, denoises it by downscaling significant coefficients in insignificant trees starting at from ending at to, using the standard deviation times alpha as threshold and writes it to outfile. For the decomposition from which the trees are obtained, a filter can be chosen. There are also two possible functions available for determining whether or not a location is significant. This can be controlled by setting sfunction to 0 (single coefficient against threshold, default), 1 (significant only if both the coefficient and most values from its 3x3 surrounding area are significant) or 2 (like 1 but only look at horizontal or vertical environments depending on areas). The coefficients considered as noise will be replaced using another function that can be set by rfunction to either 0 (simple replacement by threshold, default) or 1 (more sophisticated, determine value from horizontal, vertical or diagonal area depending on the area in the image). By default, all detail areas are processed, but optionally they can be specified using areas as a binary combination of the numbers 1 (HL), 2 (LH), 4 (HH).

NOTES

The pgmdenoise 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, pgmdenoise may, if enabled, also be able to read PFI files.

BUGS

None known yet.

COPYRIGHT
Copyright (C) 2001-2003 Herbert

pgmdenoise 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.

pgmdenoise 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>