NAME
    pbmclean - flip isolated pixels in portable bitmap

SYNOPSIS
    pbmclean [-minneighbors=N] [-black|-white] [pbmfile]

    You can  use the minimum unique abbreviation of the options. You can
    use two hyphens instead of one. You can separate an option name from
    its value with white space instead of an equals sign.

    Before December 2001, pbmclean accepted -N instead of -minneighbors.

DESCRIPTION
    pbmclean  cleans  up a PBM image of random specs. It reads a PBM image
    as input and outputs a PBM that is the same as the input except with
    every pixel which has less than N identical neighbours inverted.

    The default for N is 1 - only completely isolated pixels are flipped.

    (A value of N greater than 8 generates a completely inverted image (but
    use pnminvert to do that) -- or a completely white or completely  black
    image with the -black or -white option).

    pbmclean  considers the area beyond the edges of the image to be white.
    (This matters when you consider pixels right on the edge of the image).

    You can use pbmclean to clean up "snow" on bitmap images.

OPTIONS
    -black

    -white Flip pixels of the specified color. By default, if you specify
    neither -black nor -white, pbmclean flips both black and  white
    pixels which do not have sufficient identical neighbors. If you
    specify -black, pbmclean leaves the white pixels alone and just
    erases isolated black pixels. Vice versa for -white. You may
    specify both -black and -white to get the same as the default
    behavior.

SEE ALSO
    pbm(5)

AUTHOR
    Copyright (C) 1990 by Angus Duggan Copyright (C) 1989 by Jef Poskanzer.
    Copyright (C) 2001 by Michael Sternberg.

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