/usr/share/octave/packages/image-2.4.1/immse.m is in octave-image 2.4.1-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | ## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
##
## This program 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.
##
## This program 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 this program; if not, see
## <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn {Function File} {} immse (@var{x}, @var{y})
## Compute mean squared error.
##
## Calculates the mean squared error (MSE), between the arrays @var{x} and
## @var{y}. @var{x} and @var{y} must be of same size and class.
##
## The returned value will be a scalar double, unless @var{x} and @var{y}
## are of class single in which case, it returns a scalar single.
##
## @seealso{psnr}
## @end deftypefn
function [mse] = immse (x, y)
if (nargin != 2)
print_usage ();
elseif (! size_equal (x, y))
error ("immse: X and Y must be of same size");
elseif (! strcmp (class (x), class (y)))
error ("immse: X and Y must have same class");
end
if (isinteger (x))
x = double (x);
y = double (y);
endif
err = x - y;
mse = sumsq (err(:)) / numel (err);
endfunction
%!error <same size> immse (rand (10), rand (12))
%!error <same class> immse (uint8 ([0 1 2 3]), uint16 ([0 1 2 3]))
%!error <same class> immse (double ([0 1 2 3]), single ([0 1 2 3]))
%!assert (immse (magic (5), magic (5)), 0)
%!assert (immse (single (magic (5)), single (magic (5))), single (0))
%!assert (immse (uint8 (magic (5)), uint8 (magic (5))), 0)
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