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CentOS 7.0 - man page for pbmclean (centos section 0)

Pbmclean User Manual(0) 						  Pbmclean User Manual(0)

NAME
       pbmclean - despeckle a PBM image

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

OPTION USAGE
       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.

DESCRIPTION
       This program is part of Netpbm(1)

       pbmclean  cleans  up a PBM image of random specks.  It reads a PBM image as input and out-
       puts a PBM that is the same as the input except with isolated pixels inverted.

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

       There are two ways pbmclean can define 'isolated' pixels: simple and extended.	When  you
       specify -extended, pbmclean uses extended; otherwise it uses basic.

       In basic mode, pbmclean looks at each pixel individually, and any
       pixel  that doesn't have at least a minimum number of pixels of the same color touching it
       is considered isolated and pbmclean erases it.

       The -minneighbors option specifies the minimum number of neighboring pixels  of	the  same
       color for a pixel not to be considered isolated.

       For  example, if -minneighbors is two and there are two contiguous black pixels in an oth-
       erwise white field, each of those pixels is isolated, so pbmclean erases them - turns both
       white.

       The default minimum 1 pixel — pbmclean flips only completely isolated pixels.

       (A  -minneighbors  value  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).

       pbmclean does not distinguish between foreground and background; by default, it flips iso-
       lated  pixels  of either color.	But you can specify -black or -white to have it flip only
       pixels of one color.

       In extended mode, pbmclean erases all blobs which don't have the
       specified minimum number of pixels.  A blob is a set of contiguous  pixels  of  the  fore-
       ground  color.	The  minimum  number  of pixels is one plus the -minneighbors value.  You
       specify the foreground color with -black and -white (default is black).

       For example, if -minneighbors is 2 and the foreground color is black, and the  image  con-
       tains  a straight line 4 pixels long, pbmclean erases that -- turns all four pixels white.
       pbmclean also erases 4 pixels in a square or L-shape.

       The default -minneighbors is 4, so a blob must have at least 5 pixels to escape pbmclean's
       purge.

       Extended mode was new in Netpbm 10.56 (September 2011).

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.

       -minneighbors=N
	      This  determines how many pixels must be in a cluster in order for pbmclean to con-
	      sider them legitimate and not  clean  them  out  of  the	image.	 See  Description
	      <#description> .

	      Before December 2001, pbmclean accepted -N instead of -minneighbors.  Before Netpbm
	      10.27 (March 2005), -minneighbors was -minneighbor.

       -extended
	      pbmclean uses extended, as opposed to basic, isolated pixel detection.

	      This option was new in Netpbm 10.56 (September 2011).

SEE ALSO
       pbm(1)

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, 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.

netpbm documentation			 19 November 2011		  Pbmclean User Manual(0)


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