Mercurial > octave
view scripts/image/gray2ind.m @ 28912:0de38a6ef693
maint: Use Octave convention of space after function name in scripts dir.
* cplxpair.m, gradient.m, integral.m, integral3.m, interp2.m, interpft.m,
num2str.m, pol2cart.m, quad2d.m, quadgk.m, quadl.m, repelem.m, sph2cart.m,
convhull.m, delaunay.m, delaunayn.m, movegui.m, print_usage.m,
__strip_html_tags__.m, colormap.m, gray2ind.m, imformats.m, importdata.m,
javachk.m, condest.m, isbanded.m, krylov.m, lscov.m, rref.m, inputParser.m,
publish.m, symvar.m, validateattributes.m, ode15i.m, ode15s.m, ode23.m,
ode23s.m, ode45.m, fminbnd.m, fminsearch.m, glpk.m, qp.m, get_forge_pkg.m,
installed_packages.m, annotation.m, axis.m, camorbit.m, campos.m, camva.m,
camzoom.m, daspect.m, legend.m, pbaspect.m, __gnuplot_legend__.m, light.m,
patch.m, plotyy.m, __pie__.m, reducepatch.m, ribbon.m, streamline.m, trisurf.m,
figure.m, ndgrid.m, __gnuplot_draw_axes__.m, __opengl_print__.m, padecoef.m,
polygcd.m, ppval.m, spline.m, union.m, bicg.m, bicgstab.m, cgs.m, eigs.m,
gmres.m, pcg.m, pcr.m, __alltohandles__.m, __sprand__.m, qmr.m, tfqmr.m,
betaincinv.m, cosint.m, gammainc.m, discrete_cdf.m, discrete_inv.m,
discrete_rnd.m, base2dec.m, strtok.m, compare_plot_demos.m,
html_compare_plot_demos.m, speed.m, test.m, weboptions.m, webread.m, webwrite.m:
Use Octave convention of space after function name and before '(' in scripts
directory.
author | Rik <rik@octave.org> |
---|---|
date | Tue, 13 Oct 2020 18:17:29 -0700 |
parents | 90fea9cc9caa |
children | 7854d5752dd2 |
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######################################################################## ## ## Copyright (C) 1994-2020 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## 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 ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{img} =} gray2ind (@var{I}) ## @deftypefnx {} {@var{img} =} gray2ind (@var{I}, @var{n}) ## @deftypefnx {} {@var{img} =} gray2ind (@var{BW}) ## @deftypefnx {} {@var{img} =} gray2ind (@var{BW}, @var{n}) ## @deftypefnx {} {[@var{img}, @var{map}] =} gray2ind (@dots{}) ## Convert a grayscale or binary intensity image to an indexed image. ## ## The indexed image will consist of @var{n} different intensity values. ## If not given @var{n} defaults to 64 for grayscale images or 2 for binary ## black and white images. ## ## The output @var{img} is of class uint8 if @var{n} is less than or equal to ## 256; Otherwise the return class is uint16. ## @seealso{ind2gray, rgb2ind} ## @end deftypefn function [I, map] = gray2ind (I, n = 64) if (nargin < 1) print_usage (); elseif (! isreal (I) || issparse (I) || ! ismatrix (I)) error ("gray2ind: I must be a grayscale or binary image"); elseif (! isscalar (n) || n < 1 || n > 65536) error ("gray2ind: N must be a positive integer in the range [1, 65536]"); endif ## default n is different if image is logical if (nargin == 1 && islogical (I)) n = 2; endif cls = class (I); if (! any (strcmp (cls, {"logical", "uint8", "uint16", "int16", ... "single", "double"}))) error ("gray2ind: invalid data type '%s'", cls); elseif (isfloat (I) && (min (I(:) < 0) || max (I(:) > 1))) error ("gray2ind: floating point images may only contain values between 0 and 1"); endif map = gray (n); ## Set up scale factor if (isinteger (I)) low = double (intmin (cls)); scale = double (intmax (cls)) - low; I = double (I) - low; else scale = 1; endif I *= (n-1)/scale; ## Note: no separate call to round () necessary because ## type conversion does that automatically. if (n <= 256) I = uint8 (I); else I = uint16 (I); endif endfunction %!assert (gray2ind ([0 0.25 0.5 1]), uint8 ([0 16 32 63])) %!assert (gray2ind ([0 0.25 0.5 1], 400), uint16 ([0 100 200 399])) %!assert (gray2ind (logical ([1 0 0 1])), uint8 ([1 0 0 1])) %!assert (gray2ind (uint8 ([0 64 128 192 255])), uint8 ([0 16 32 47 63])) %!test %! i2g = ind2gray (1:100, gray (100)); %! g2i = gray2ind (i2g, 100); %! assert (g2i, uint8 (0:99)); %!assert (gray2ind ([0 0.25 0.5 1], 256), uint8 ([0 64 128 255])) %!assert (gray2ind ([0 (1/511) (1/510) 1-(1/509) 1-(1/510) 1], 256), %! uint8 ([0 0 1 254 255 255])) %!test %! assert (class (gray2ind ([0.0 0.5 1.0], 255)), "uint8"); %! assert (class (gray2ind ([0.0 0.5 1.0], 256)), "uint8"); %! assert (class (gray2ind ([0.0 0.5 1.0], 257)), "uint16"); ## Test input validation %!error <Invalid call> gray2ind () %!error <I must be a grayscale or binary image> gray2ind ({1}) %!error <I must be a grayscale or binary image> gray2ind ([1+i]) %!error <I must be a grayscale or binary image> gray2ind (sparse ([1])) %!error <I must be a grayscale or binary image> gray2ind (ones (2,2,3)) %!error <N must be a positive integer> gray2ind (1, ones (2,2)) %!error <N must be a positive integer> gray2ind (1, 0) %!error <N must be a positive integer> gray2ind (1, 65537) %!error <invalid data type> gray2ind (uint32 (1)) %!error <values between 0 and 1> gray2ind (-1) %!error <values between 0 and 1> gray2ind (2)