% Returns the mean value for a 2d real type matrix.
SYNOPSIS
function m = mean2 (I)
DESCRIPTION
% -*- texinfo -*-
% @deftypefn {Function File} @var{m}= mean2 (@var{I})
% Returns the mean value for a 2d real type matrix.
% Uses @code{mean(I(:))}
% @seealso{std2,mean}
% @end deftypefn
