Mercurial > octave-antonio
view scripts/image/contrast.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 | b1cd65881592 |
children | d63878346099 |
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## Copyright (C) 2008-2012 David Bateman ## ## 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{cmap} =} contrast (@var{x}) ## @deftypefnx {Function File} {@var{cmap} =} contrast (@var{x}, @var{n}) ## Return a gray colormap that maximizes the contrast in an image. The ## returned colormap will have @var{n} rows. If @var{n} is not defined ## then the size of the current colormap is used. ## @seealso{colormap, brighten} ## @end deftypefn function cmap = contrast (x, n) if (nargin == 1) n = rows (colormap ()); elseif (nargin == 2) if (! isscalar (n)) error ("contrast: N must be a scalar"); endif else print_usage (); endif x = x(:); minx = min (x); cmap = find (diff (sort ([round(n * ((x - minx) ./ (max(x) - minx))); [0:n]']))); minm = min (cmap); cmap = (cmap - minm) ./ (max (cmap) - minm); cmap = [cmap, cmap, cmap]; endfunction %!demo %! figure; %! img = reshape (1:100, 10, 10); %! imagesc (img); %! colormap (gray (64)); %! title ("Image with default 64 gray levels"); %! pos = get (gcf, "position"); %! pos(1) += pos(3) + 25; %! figure ("position", pos); %! colormap (contrast (img, 10)); %! imagesc (img); %! title ("Image with contrast enhanced"); %!assert (contrast (1:100,10), [([0:9]/9)',([0:9]/9)',([0:9]/9)'], 1e-10)