## Copyright (C) 2000 Kai Habel <kai.habel@gmx.de>
##
## 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} {@var{m}=} mean2 (@var{I})
## Compute the mean value of the 2D image @var{I}.
##
## Note that @var{m} will be of class double, independently of the input class.
## This is equivalent to @code{mean (I(:))}.
##
## @seealso{mean, std2}
## @end deftypefn

function m = mean2 (I)

  if (nargin != 1)
    print_usage();
  elseif (!isimage (I) || ndims (I) != 2)
    error("mean2: argument must be a 2D image");
  endif
  m = mean (I(:));
endfunction