%IM_MEAN Computation of the centers of gravity of images%%   B = IM_MEAN(A)%   B = A*IM_MEAN%% INPUT%   A        Dataset with object images dataset (possibly multi-band)%% OUTPUT%   B        Dataset with centers-of-gravity replacing images %            (possibly multi-band). The first component is always measured%            in the horizontal direction (X).%% DESCRIPTION% Computes the centers of gravity of all images stored in A.% This center is computed, relative to the top-left corner of the image.%% SEE ALSO% DATASETS, DATAFILES% Copyright: R.P.W. Duin, r.p.w.duin@prtools.org% Faculty EWI, Delft University of Technology% P.O. Box 5031, 2600 GA Delft, The Netherlandsfunction b = im_mean(a)	prtrace(mfilename);	  if nargin < 1 | isempty(a)    b = mapping(mfilename,'fixed');    b = setname(b,'Image centers');	elseif isa(a,'dataset') % allows datafiles too		isobjim(a);    b = filtim(a,mfilename);  elseif isa(a,'double') % here we have a single image		if isa(a,'dip_image'), a = double(a); end		[m,n] = size(a);		g = sum(sum(a));		JX = repmat([1:n],m,1);		JY = repmat([1:m]',1,n);		mx = sum(sum(a.*JX))/g;		my = sum(sum(a.*JY))/g;		b = [mx/n my/m];	end	return