Mercurial > octave
view scripts/image/rgb2gray.m @ 28886:d8318c12d903
test: remove unnecessary BIST tests in m-files checking for excessive number of inputs.
Remove BIST tests now that interpreter enforces calling function with no more than
the number of arguments defined in the function prototype.
* makeUniqueStrings.m, makeValidName.m, base64decode.m, base64encode.m,
record.m, sound.m, soundsc.m, acosd.m, acot.m, acotd.m, acoth.m, acsc.m,
acscd.m, acsch.m, asec.m, asecd.m, asech.m, asind.m, atan2d.m, atand.m, cosd.m,
cot.m, cotd.m, coth.m, csc.m, cscd.m, csch.m, sec.m, secd.m, sech.m, sind.m,
tand.m, accumdim.m, bincoeff.m, bitget.m, bitset.m, cell2mat.m, circshift.m,
cplxpair.m, cumtrapz.m, deg2rad.m, flip.m, fliplr.m, flipud.m, int2str.m,
interpft.m, logspace.m, num2str.m, postpad.m, prepad.m, rad2deg.m, rot90.m,
rotdim.m, shift.m, subsindex.m, trapz.m, rotx.m, roty.m, rotz.m, getappdata.m,
getpixelposition.m, guidata.m, isappdata.m, waitforbuttonpress.m,
__gripe_missing_component__.m, bessel.m, hsv2rgb.m, ind2gray.m, rgb2gray.m,
rgb2hsv.m, rgbplot.m, fileread.m, javachk.m, usejava.m, findstr.m,
genvarname.m, isdir.m, vectorize.m, cond.m, cross.m, duplication_matrix.m,
expm.m, isbanded.m, isdefinite.m, isdiag.m, ishermitian.m, issymmetric.m,
istril.m, istriu.m, trace.m, vech.m, vecnorm.m, cast.m, citation.m,
compare_versions.m, grabcode.m, inputname.m, isfile.m, isfolder.m, ismac.m,
ispc.m, isunix.m, list_primes.m, methods.m, news.m, open.m, run.m, swapbytes.m,
tar.m, verLessThan.m, zip.m, odeget.m, optimget.m, stemleaf.m, allchild.m,
ancestor.m, close.m, groot.m, hgsave.m, isaxes.m, isfigure.m, isgraphics.m,
ishandle.m, isprop.m, linkaxes.m, rotate.m, saveas.m, conv.m, poly.m,
polyint.m, polyreduce.m, ppval.m, roots.m, addpref.m, getpref.m, ispref.m,
rmpref.m, setpref.m, profile.m, profshow.m, powerset.m, autoreg_matrix.m,
bartlett.m, blackman.m, detrend.m, fftconv.m, fftfilt.m, fftshift.m, hamming.m,
hanning.m, ifftshift.m, sinewave.m, spectral_adf.m, spectral_xdf.m, unwrap.m,
nonzeros.m, spconvert.m, sprand.m, sprandn.m, beta.m, betainc.m, betaln.m,
cosint.m, expint.m, factorial.m, legendre.m, nchoosek.m, nthroot.m, perms.m,
pow2.m, primes.m, reallog.m, realpow.m, realsqrt.m, sinint.m, hankel.m, hilb.m,
invhilb.m, magic.m, pascal.m, toeplitz.m, vander.m, wilkinson.m, center.m,
corr.m, cov.m, discrete_cdf.m, discrete_inv.m, discrete_pdf.m, empirical_cdf.m,
empirical_inv.m, empirical_pdf.m, iqr.m, kendall.m, kurtosis.m, mad.m,
meansq.m, median.m, moment.m, prctile.m, quantile.m, range.m, run_count.m,
skewness.m, spearman.m, statistics.m, std.m, var.m, base2dec.m, bin2dec.m,
blanks.m, dec2base.m, dec2bin.m, dec2hex.m, endsWith.m, erase.m, hex2dec.m,
index.m, isletter.m, isstring.m, isstrprop.m, mat2str.m, ostrsplit.m, rindex.m,
startsWith.m, strtrunc.m, substr.m, fail.m, addtodate.m, asctime.m, ctime.m,
date.m, datestr.m, eomday.m, etime.m, is_leap_year.m, now.m:
remove unnecessary BIST tests in m-files checking for excessive number of inputs.
author | Rik <rik@octave.org> |
---|---|
date | Fri, 09 Oct 2020 13:28:53 -0700 |
parents | bd51beb6205e |
children | de5f2f9a64ff |
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######################################################################## ## ## Copyright (C) 2018-2020 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{I} =} rgb2gray (@var{rgb_img}) ## @deftypefnx {} {@var{gray_map} =} rgb2gray (@var{rgb_map}) ## Transform an image or colormap from red-green-blue (RGB) color space to ## a grayscale intensity image. ## ## The input may be of class uint8, int8, uint16, int16, single, or double. ## The output is of the same class as the input. ## ## Implementation Note: ## The grayscale intensity is calculated as ## ## @example ## @group ## @var{I} = 0.298936*@var{R} + 0.587043*@var{G} + 0.114021*@var{B} ## @end group ## @end example ## ## @noindent ## which corresponds to the luminance channel when RGB is translated to ## @nospell{YIQ} as documented in @url{https://en.wikipedia.org/wiki/YIQ}. ## @seealso{rgb2hsv, rgb2ind} ## @end deftypefn function I = rgb2gray (rgb) if (nargin != 1) print_usage (); endif is_int = isinteger (rgb); if (is_int) cls = class (rgb); endif [rgb, sz, is_im, is_nd] ... = colorspace_conversion_input_check ("rgb2gray", "RGB", rgb); ## Reference matrix for transform from http://en.wikipedia.org/wiki/YIQ. ## Matlab uses this matrix for their conversion with oddly more precision. xform = [0.298936; 0.587043; 0.114021]; I = rgb * xform; sz(3) = 1; # grayscale images have 3rd dimension of length 1 I = colorspace_conversion_revert (I, sz, is_im, is_nd); ## Restore integer class if necessary if (is_int) if (cls(end) == "8") # uint8 or int8 I *= 255; if (cls(1) == "i") # int8 I -= 128; endif else # uint16 or int16 I *= 65535; if (cls(1) == "i") # int16 I -= 32768; endif endif I = feval (cls, I); endif endfunction ## Test pure RED, GREEN, BLUE colors %!assert (rgb2gray ([1 0 0]), 0.298936) %!assert (rgb2gray ([0 1 0]), 0.587043) %!assert (rgb2gray ([0 0 1]), 0.114021) ## test tolerance input checking on floats %! assert (rgb2gray ([1.5 1 1]), 1.149468, -1.6e-3); ## Test ND input %!test %! rgb = rand (16, 16, 3, 5); %! I = zeros (16, 16, 1, 5); %! for i = 1:5 %! I(:,:,1,i) = rgb2gray (rgb(:,:,:,i)); %! endfor %! assert (rgb2gray (rgb), I); ## Test output class and size for input images. ## Most of the tests only test for colormap input. %!test %! I = rgb2gray (rand (10, 10, 3)); %! assert (class (I), "double"); %! assert (size (I), [10 10]); %!test %! I = rgb2gray (rand (10, 10, 3, "single")); %! assert (class (I), "single"); %! assert (size (I), [10 10]); %!test %! rgb = (rand (10, 10, 3) * 3 ) - 0.5; # values outside range [0 1] %! I = rgb2gray (rgb); %! assert (class (I), "double"); %! assert (size (I), [10 10]); %!test %! rgb = (rand (10, 10, 3, "single") * 3 ) - 0.5; # values outside range [0 1] %! I = rgb2gray (rgb); %! assert (class (I), "single"); %! assert (size (I), [10 10]); %!test %! I = rgb2gray (randi ([0 255], 10, 10, 3, "uint8")); %! assert (class (I), "uint8"); %! assert (size (I), [10 10]); %!test %! I = rgb2gray (randi ([0 65535], 10, 10, 3, "uint16")); %! assert (class (I), "uint16"); %! assert (size (I), [10 10]); %!test %! I = rgb2gray (randi ([-128 127], 10, 10, 3, "int8")); %! assert (class (I), "int8"); %! assert (size (I), [10 10]); %!test %! I = rgb2gray (randi ([-32768 32767], 10, 10, 3, "int16")); %! assert (class (I), "int16"); %! assert (size (I), [10 10]); %!test %! rgb_double = reshape ([1 0 0 0 0 1 0 0 0 0 1 0], [2 2 3]); %! rgb_uint8 = reshape (uint8 ([255 0 0 0 0 255 0 0 0 0 255 0]), %! [2 2 3]); %! rgb_int16 = int16 (double (rgb_double * uint16 (65535)) - 32768); %! expected = [0.298936, 0.114021; 0.587043, 0.0]; %! %! assert (rgb2gray (rgb_double), expected); %! assert (rgb2gray (rgb_uint8), uint8 (expected*255)); %! assert (rgb2gray (single (rgb_double)), single (expected)); ## Test input validation %!error <Invalid call> rgb2gray () %!error <invalid data type 'cell'> rgb2gray ({1}) %!error <RGB must be a colormap or RGB image> rgb2gray (ones (2,2))