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Ppmcolormask User Manual(0) Ppmcolormask User Manual(0)
NAME
ppmcolormask - produce mask of areas of a certain color in a PPM file
SYNOPSIS
ppmcolormask -color=color_list [ppmfile]
ppmcolormask color [ppmfile]
EXAMPLES
ppmcolormask -color red testimg.ppm >redmask.pbm
pamcomp background.ppm testimg.ppm -alpha=redmask.pbm >test.ppm
ppmcolormask -color=red,pink,salmon testimg.ppm >reddishmask.pbm
ppmcolormask -color=bk:red,bk:orange,bk:yellow testimg.ppm >firemask.pbm
DESCRIPTION
This program is part of Netpbm(1)
ppmcolormask reads a PPM file as input and produces a PBM (bitmap) file
as output. The output file is the same dimensions as the input file
and is black in all places where the input file is a color indicated by
the -color option, and white everywhere else.
The output of ppmcolormask is useful as an alpha mask input to pamcomp.
Note that you can generate such an alpha mask automatically as you con-
vert to PNG format with pnmtopng(1) option.
ppmfile is the input file. If you don't specify ppmfile, the input is
from Standard Input.
The output goes to Standard Output.
In the obsolete alternative syntax, specifying the color names a single
exact color to be masked.
ppmchange does a similar thing: it modifies an image by changing colors
you specify to other colors you specify. The two programs give you
somewhat different means of specifying colors in the input image.
To make a mask of an image's background, without having to tell it what
color it is, use pambackground.
OPTIONS
-color=color_list
This mandatory option specifies the colors that are to be masked
(where the image is one of these colors, the output mask will be
black).
Examples:
o -color=red
o -color=red,pink,salmon
o -color=rgb:80/80/ff
o -color=bk:red,bk:orange,bk:yellow
color_list is a list of colors separated by commas. Each color
is either an exact color name as described for the argument of
the ppm_parsecolor() library routine <libppm.html#colorname> or
one of the Berlin-Kay color names <libppm.html#berlinkay> . In
the latter case, all colors that are better described by that
Berlin-Kay color name than any other are in the mask set.
The algorithm ppmcolormask uses to determine to which colors a
Berlin-Kay color name applies is based on a Sugeno-type fuzzy
inference system developed by Kenan Kalajdzic in 2006. The
fuzzy model consists of partially linear membership functions
defined in the HSV color space. Although more complex algo-
rithms for fuzzy color matching exist, this algorithm is inten-
tionally simplified to achieve a satisfactory speed using rela-
tively compact code.
This option was new in Netpbm 10.34 (June 2006). Before that,
you must use the color argument and cannot specify a Berlin-Kay
color.
SEE ALSO
pambackground(1) , ppmchange(1) , pgmtoppm(1) , pamcomp(1) , pbmmask(1)
, ppm(5)
netpbm documentation 1 May 2006 Ppmcolormask User Manual(0)
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