Mercurial > octave-antonio
view scripts/image/ntsc2rgb.m @ 17170:d6499c14021c
doc: Periodic grammarcheck of documentation.
* doc/interpreter/basics.txi, doc/interpreter/expr.txi,
doc/interpreter/install.txi, doc/interpreter/java.txi,
doc/interpreter/plot.txi, doc/interpreter/sparse.txi,
doc/interpreter/vectorize.txi, libinterp/corefcn/cellfun.cc,
libinterp/corefcn/debug.cc, libinterp/corefcn/file-io.cc,
libinterp/corefcn/load-save.cc, libinterp/corefcn/matrix_type.cc,
libinterp/corefcn/pr-output.cc, libinterp/parse-tree/oct-parse.in.yy,
liboctave/numeric/LSODE-opts.in, scripts/image/imformats.m,
scripts/image/imread.m, scripts/image/imwrite.m,
scripts/miscellaneous/error_ids.m, scripts/miscellaneous/fileattrib.m,
scripts/miscellaneous/mex.m, scripts/miscellaneous/mkoctfile.m,
scripts/miscellaneous/warning_ids.m, scripts/prefs/prefdir.m,
scripts/prefs/preferences.m, scripts/signal/fftfilt.m,
scripts/strings/isstrprop.m, scripts/testfun/assert.m:
Periodic grammarcheck of documentation.
author | Rik <rik@octave.org> |
---|---|
date | Sun, 04 Aug 2013 13:08:39 -0700 |
parents | 3d2357969627 |
children | d63878346099 |
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## Copyright (C) 1994-2012 John W. Eaton ## ## 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{rgb_map} =} ntsc2rgb (@var{yiq_map}) ## @deftypefnx {Function File} {@var{rgb_img} =} ntsc2rgb (@var{yiq_img}) ## Transform a colormap or image from luminance-chrominance (NTSC) space to ## red-green-blue (RGB) color space. ## ## Implementation Note: ## The conversion matrix is chosen to be the inverse of the ## matrix used for rgb2ntsc such that ## ## @example ## x == ntsc2rgb (rgb2ntsc (x)) ## @end example ## ## @sc{matlab} uses a slightly different matrix where rounding ## means the equality above does not hold. ## @seealso{rgb2ntsc, hsv2rgb, ind2rgb} ## @end deftypefn ## Author: Tony Richardson <arichard@stark.cc.oh.us> ## Created: July 1994 ## Adapted-By: jwe function rgb = ntsc2rgb (yiq) if (nargin != 1) print_usage (); endif if (! isa (yiq, "double")) error ("ntsc2rgb: YIQ must be of type double"); endif ## If we have an image convert it into a color map. if (ismatrix (yiq) && ndims (yiq) == 3) is_image = true; sz = size (yiq); yiq = [yiq(:,:,1)(:), yiq(:,:,2)(:), yiq(:,:,3)(:)]; else is_image = false; endif if (! isreal (yiq) || columns (yiq) != 3 || issparse (yiq)) error ("ntsc2rgb: input must be a matrix of size Nx3 or NxMx3"); endif ## Conversion matrix constructed from 'inv (rgb2ntsc matrix)'. ## See programming notes in rgb2ntsc.m. Note: Matlab matrix for inverse ## is slightly different. We prefer this matrix so that ## x == ntsc2rgb (rgb2ntsc (x)) rather than maintaining strict compatibility ## with Matlab. trans = [ 1.0, 1.0, 1.0; 0.95617, -0.27269, -1.10374; 0.62143, -0.64681, 1.70062 ]; rgb = yiq * trans; ## If input was an image, convert it back into one. if (is_image) rgb = reshape (rgb, sz); endif endfunction %% Test pure R, G, B colors %!assert (ntsc2rgb ([.299 .596 .211]), [1 0 0], 1e-5) %!assert (ntsc2rgb ([.587 -.274 -.523]), [0 1 0], 1e-5) %!assert (ntsc2rgb ([.114 -.322 .312]), [0 0 1], 1e-5) %!test %! rgb_map = rand (64, 3); %! assert (ntsc2rgb (rgb2ntsc (rgb_map)), rgb_map, 1e-3); %!test %! rgb_img = rand (64, 64, 3); %! assert (ntsc2rgb (rgb2ntsc (rgb_img)), rgb_img, 1e-3); %% Test input validation %!error ntsc2rgb () %!error ntsc2rgb (1,2) %!error <YIQ must be of type double> ntsc2rgb (uint8 (1)) %!error <must be a matrix of size Nx3 or NxMx3> ntsc2rgb (ones (2,2))