Mercurial > octave
view scripts/image/im2double.m @ 30564:796f54d4ddbf stable
update Octave Project Developers copyright for the new year
In files that have the "Octave Project Developers" copyright notice,
update for 2021.
In all .txi and .texi files except gpl.txi and gpl.texi in the
doc/liboctave and doc/interpreter directories, change the copyright
to "Octave Project Developers", the same as used for other source
files. Update copyright notices for 2022 (not done since 2019). For
gpl.txi and gpl.texi, change the copyright notice to be "Free Software
Foundation, Inc." and leave the date at 2007 only because this file
only contains the text of the GPL, not anything created by the Octave
Project Developers.
Add Paul Thomas to contributors.in.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Tue, 28 Dec 2021 18:22:40 -0500 |
parents | 7854d5752dd2 |
children | 5d3faba0342e |
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######################################################################## ## ## Copyright (C) 2007-2022 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 {} {} im2double (@var{img}) ## @deftypefnx {} {} im2double (@var{img}, "indexed") ## Convert image to double precision. ## ## The conversion of @var{img} to double precision, is dependent ## on the type of input image. The following input classes are ## supported: ## ## @table @samp ## @item uint8, uint16, and int16 ## The range of values from the class is scaled to the interval [0 1]. ## ## @item logical ## True and false values are assigned a value of 0 and 1 respectively. ## ## @item single ## Values are cast to double. ## ## @item double ## Returns the same image. ## ## @end table ## ## If @var{img} is an indexed image, then the second argument should be ## the string @qcode{"indexed"}. If so, then @var{img} must either be ## of floating point class, or unsigned integer class and it will simply ## be cast to double. If it is an integer class, a +1 offset is applied. ## ## @seealso{double} ## @end deftypefn function img = im2double (img, im_type) if (nargin < 1) print_usage (); endif if (nargin == 1) ## "normal" (non-indexed) images switch (class (img)) case "uint8", img = double (img) / 255; case "uint16", img = double (img) / 65535; case "int16", img = (double (img) + 32768) / 65535; case "single", img = double (img); case "logical", img = double (img); case "double", # do nothing otherwise, error ('im2double: IMG is of unsupported class "%s"', class (img)); endswitch else ## indexed images if (! strcmpi (im_type, "indexed")) error ('im2double: second input argument must be the string "indexed"'); elseif (any (isa (img, {"uint8", "uint16"}))) img = double (img) + 1; elseif (isfloat (img) || isbool (img)) img = double (img); else ## Technically, it could also be of logical class and we do not ## enforce positive integers for floating for Matlab compatibility. ## Still, no need to tell that to the user. error (["im2double: if IMG is indexed, then it must be positive " ... "integer floating points, or unsigned integer class"]); endif endif endfunction %!assert (im2double ([1 2 3]), [1 2 3]) %!assert (im2double (single ([1 2 3])), [1 2 3]) %!assert (im2double (uint8 ([0 127 128 255])), [0 127/255 128/255 1]) %!assert (im2double (uint16 ([0 127 128 65535])), [0 127/65535 128/65535 1]) %!assert (im2double (int16 ([-32768 -32767 -32766 32767])), %! [0 1/65535 2/65535 1]) %!assert (im2double (uint8 ([0 1 255]), "indexed"), [1 2 256]) %!assert (im2double (uint16 ([0 1 2557]), "indexed"), [1 2 2558]) %!assert (im2double ([3 25], "indexed"), [3 25]) %!assert (im2double (single ([3 25]), "indexed"), [3 25]) ## Test for ND input %!function test_im2double_nd (cls, low, high) %! in = rand (2, 4, 2, 3, 2); %! in *= high - low; %! in += low; %! in = cast (in, cls); %! out = zeros (size (in)); %! for n = 1:12 %! out(:,:,n) = im2double (in(:,:,n)); %! endfor %! assert (im2double (in), out); %!endfunction %!test %! test_im2double_nd ("double", 0, 1); %! test_im2double_nd ("single", 0, 1); %! test_im2double_nd ("uint8", 0, 255); %! test_im2double_nd ("uint16", 0, 6535); %! test_im2double_nd ("int16", -32768, 32767); ## Test lack of input check for Matlab compatibility %!assert (im2double ([0 1 2], "indexed"), [0 1 2]) %!assert (im2double ([0 -1 -2], "indexed"), [0 -1 -2]) %!assert (im2double ([0 -1.5 -2], "indexed"), [0 -1.5 -2]) %!assert (im2double ([0 -1.5 -2i], "indexed"), [0 -1.5 -2i]) %!assert (im2double ([false true], "indexed"), [0 1]) %!error <unsigned integer class> im2double (int16 ([17 8]), "indexed") %!error <unsigned integer class> im2double (int16 ([-7 8]), "indexed") %!error <must be the string "indexed"> im2double ([1 2 3], "non-indexed")