Mercurial > octave-antonio
view scripts/image/rgb2ind.m @ 20158:7503499a252b stable
doc: Update docstrings to have one sentence summary as first line.
Update scripts in audio, elfun, general, geometry, and image directories.
* scripts/audio/@audioplayer/__get_properties__.m,
scripts/audio/@audioplayer/audioplayer.m, scripts/audio/@audioplayer/get.m,
scripts/audio/@audioplayer/isplaying.m, scripts/audio/@audioplayer/play.m,
scripts/audio/@audioplayer/playblocking.m, scripts/audio/@audioplayer/set.m,
scripts/audio/@audioplayer/subsasgn.m, scripts/audio/@audioplayer/subsref.m,
scripts/audio/@audiorecorder/audiorecorder.m,
scripts/audio/@audiorecorder/get.m,
scripts/audio/@audiorecorder/getaudiodata.m,
scripts/audio/@audiorecorder/getplayer.m,
scripts/audio/@audiorecorder/isrecording.m,
scripts/audio/@audiorecorder/play.m, scripts/audio/@audiorecorder/record.m,
scripts/audio/@audiorecorder/recordblocking.m,
scripts/audio/@audiorecorder/set.m, scripts/audio/@audiorecorder/stop.m,
scripts/audio/@audiorecorder/subsasgn.m,
scripts/audio/@audiorecorder/subsref.m, scripts/audio/lin2mu.m,
scripts/audio/mu2lin.m, scripts/audio/record.m, scripts/audio/sound.m,
scripts/audio/soundsc.m, scripts/audio/wavread.m, scripts/audio/wavwrite.m,
scripts/elfun/cosd.m, scripts/elfun/sind.m, scripts/elfun/tand.m,
scripts/general/accumarray.m, scripts/general/accumdim.m,
scripts/general/bitcmp.m, scripts/general/bitget.m, scripts/general/bitset.m,
scripts/general/blkdiag.m, scripts/general/cart2pol.m,
scripts/general/cart2sph.m, scripts/general/cell2mat.m,
scripts/general/celldisp.m, scripts/general/chop.m,
scripts/general/circshift.m, scripts/general/common_size.m,
scripts/general/cplxpair.m, scripts/general/cumtrapz.m,
scripts/general/dblquad.m, scripts/general/deal.m, scripts/general/del2.m,
scripts/general/display.m, scripts/general/divergence.m,
scripts/general/fieldnames.m, scripts/general/flip.m,
scripts/general/flipdim.m, scripts/general/fliplr.m, scripts/general/flipud.m,
scripts/general/gradient.m, scripts/general/interp3.m,
scripts/general/interpft.m, scripts/general/interpn.m,
scripts/general/loadobj.m, scripts/general/logspace.m,
scripts/general/methods.m, scripts/general/nargchk.m,
scripts/general/narginchk.m, scripts/general/nargoutchk.m,
scripts/general/nextpow2.m, scripts/general/nthargout.m,
scripts/general/num2str.m, scripts/general/pol2cart.m,
scripts/general/polyarea.m, scripts/general/postpad.m,
scripts/general/prepad.m, scripts/general/profile.m, scripts/general/quadgk.m,
scripts/general/quadl.m, scripts/general/quadv.m, scripts/general/randi.m,
scripts/general/rat.m, scripts/general/repmat.m, scripts/general/rot90.m,
scripts/general/rotdim.m, scripts/general/saveobj.m, scripts/general/shift.m,
scripts/general/shiftdim.m, scripts/general/sortrows.m,
scripts/general/sph2cart.m, scripts/general/structfun.m,
scripts/general/subsindex.m, scripts/general/trapz.m,
scripts/general/triplequad.m, scripts/geometry/delaunayn.m,
scripts/geometry/dsearch.m, scripts/geometry/dsearchn.m,
scripts/geometry/griddata.m, scripts/geometry/griddata3.m,
scripts/geometry/griddatan.m, scripts/geometry/inpolygon.m,
scripts/geometry/rectint.m, scripts/geometry/tsearchn.m,
scripts/geometry/voronoi.m, scripts/geometry/voronoin.m,
scripts/help/__unimplemented__.m, scripts/help/doc.m,
scripts/help/doc_cache_create.m, scripts/help/get_first_help_sentence.m,
scripts/help/help.m, scripts/help/lookfor.m, scripts/help/print_usage.m,
scripts/help/type.m, scripts/help/which.m, scripts/image/autumn.m,
scripts/image/bone.m, scripts/image/brighten.m, scripts/image/cmpermute.m,
scripts/image/colorcube.m, scripts/image/contrast.m, scripts/image/cool.m,
scripts/image/copper.m, scripts/image/cubehelix.m, scripts/image/flag.m,
scripts/image/gmap40.m, scripts/image/gray.m, scripts/image/gray2ind.m,
scripts/image/hot.m, scripts/image/hsv.m, scripts/image/image.m,
scripts/image/imagesc.m, scripts/image/imfinfo.m, scripts/image/imformats.m,
scripts/image/imread.m, scripts/image/imshow.m, scripts/image/imwrite.m,
scripts/image/iscolormap.m, scripts/image/jet.m, scripts/image/lines.m,
scripts/image/ntsc2rgb.m, scripts/image/ocean.m, scripts/image/pink.m,
scripts/image/prism.m, scripts/image/rainbow.m, scripts/image/rgb2ntsc.m,
scripts/image/spinmap.m, scripts/image/spring.m, scripts/image/summer.m,
scripts/image/white.m, scripts/image/winter.m:
Update docstrings to have one sentence summary as first line.
Re-structure to have line lengths <= 80 chars.
author | Rik <rik@octave.org> |
---|---|
date | Sun, 03 May 2015 09:36:20 -0700 |
parents | 21dbaf135667 |
children |
line wrap: on
line source
## Copyright (C) 1994-2015 John W. Eaton ## Copyright (C) 2012 Carnë Draug ## ## This file is part of Octave. ## ## Octave 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 3 of the License, or (at ## your option) any later version. ## ## Octave 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. ## ## You should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{rgb}) ## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{R}, @var{G}, @var{B}) ## Convert an image in red-green-blue (RGB) color space to an indexed image. ## ## The input image @var{rgb} can be specified as a single matrix of size ## @nospell{MxNx3}, or as three separate variables, @var{R}, @var{G}, and ## @var{B}, its three color channels, red, green, and blue. ## ## It outputs an indexed image @var{x} and a colormap @var{map} to interpret ## an image exactly the same as the input. No dithering or other form of color ## quantization is performed. The output class of the indexed image @var{x} ## can be uint8, uint16 or double, whichever is required to specify the ## number of unique colors in the image (which will be equal to the number ## of rows in @var{map}) in order ## ## Multi-dimensional indexed images (of size @nospell{MxNx3xK}) are also ## supported, both via a single input (@var{rgb}) or its three color channels ## as separate variables. ## ## @seealso{ind2rgb, rgb2hsv, rgb2ntsc} ## @end deftypefn ## FIXME: This function has a very different syntax than the Matlab ## one of the same name. ## Octave function does not support N, MAP, DITHER, or TOL arguments. ## Author: Tony Richardson <arichard@stark.cc.oh.us> ## Created: July 1994 ## Adapted-By: jwe function [x, map] = rgb2ind (R, G, B) if (nargin != 1 && nargin != 3) print_usage (); endif if (nargin == 1) rgb = R; if (ndims (rgb) > 4 || size (rgb, 3) != 3) error ("rgb2ind: argument is not an RGB image"); else R = rgb(:,:,1,:); G = rgb(:,:,2,:); B = rgb(:,:,3,:); endif elseif (! size_equal (R, G, B)) error ("rgb2ind: R, G, and B must have the same size"); endif x = reshape (1:numel (R), size (R)); map = unique ([R(:) G(:) B(:)], "rows"); [~, x] = ismember ([R(:) G(:) B(:)], map, "rows"); x = reshape (x, size (R)); ## a colormap is of class double and values between 0 and 1 switch (class (R)) case {"single", "double", "logical"} ## do nothing, return the same case {"uint8", "uint16"} map = double (map) / double (intmax (class (R))); case "int16" map = (double (im) + 32768) / 65535; otherwise error ("unsupported image class %s", im_class); endswitch ## we convert to the smallest class necessary to encode the image. Matlab ## documentation does not mention what it does when uint16 is not enough... ## When an indexed image is of integer class, there's a -1 offset to the ## colormap, hence the adjustment if (rows (map) < 256) x = uint8 (x - 1); elseif (rows (map) < 65536) x = uint16 (x - 1); else ## leave it as double endif endfunction ## Test input validation %!error rgb2ind () %!error rgb2ind (1,2,3,4,5,6,7) %!error <RGB> rgb2ind (rand (10, 10, 4)) ## FIXME: the following tests simply make sure that rgb2ind and ind2rgb ## reverse each other. We should have better tests for this. ## Typical usage %!test %! rgb = rand (10, 10, 3); %! [ind, map] = rgb2ind (rgb); %! assert (ind2rgb (ind, map), rgb); %! %! ## test specifying the RGB channels separated %! [ind, map] = rgb2ind (rgb(:,:,1), rgb(:,:,2), rgb(:,:,3)); %! assert (ind2rgb (ind, map), rgb); ## Test N-dimensional images %!test %! rgb = rand (10, 10, 3, 10); %! [ind, map] = rgb2ind (rgb); %! assert (ind2rgb (ind, map), rgb); %! [ind, map] = rgb2ind (rgb(:,:,1,:), rgb(:,:,2,:), rgb(:,:,3,:)); %! assert (ind2rgb (ind, map), rgb); ## Test output class %!test %! ## this should have more than 65536 unique colors %! rgb = rand (1000, 1000, 3); %! [ind, map] = rgb2ind (rgb); %! assert (class (ind), "double"); %! assert (class (map), "double"); %! %! ## and this should have between 255 and 65536 unique colors %! rgb = rand (20, 20, 3); %! [ind, map] = rgb2ind (rgb); %! assert (class (ind), "uint16"); %! assert (class (map), "double"); %! %! ## and this certainly less than 256 unique colors %! rgb = rand (10, 10, 3); %! [ind, map] = rgb2ind (rgb); %! assert (class (ind), "uint8"); %! assert (class (map), "double");