pgmnorm

Section: User Commands (1)
Updated: 28 February 1989
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NAME

pgmnorm - normalize the contrast in a portable graymap

SYNOPSIS

pgmnorm [-bpercent <n> | -bvalue <n>] [-wpercent <n> | -wvalue] [pgmfile]

DESCRIPTION

Reads a portable graymap as input. Normalizes the contrast by forcing the lightest pixels to white, the darkest pixels to black, and linearly rescaling the ones in between; and produces a portable graymap as output.

By default, the darkest 2 percent of all pixels are mapped to black, and the lightest 1 percent are mapped to white. You can override these percentages by using the -bpercent and -wpercent flags, or you can specify the exact pixel values to be mapped by using the -bvalue and -wvalue flags. Appropriate numbers for the flags can be gotten from the pgmhist tool.

All flags can be abbreviated to their shortest unique prefix.

AUTHOR

Partially based on the fbnorm filter in Michael Mauldin's "Fuzzy Pixmap" package.

Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. This software is provided "as is" without express or implied warranty.