bias3d(x, y, ws, absval)

function [bs, bm, bmaps] = bias3d(x, y, ws, absval)

% Focal Bias for 3D images/arrays (m*n*z)

% 27/01/2013     -  Version 1.0
% 21/02/2013     -  Version 2.0

% Author:           Aristidis D. Vaiopoulos

if nargin == 2
   ws = 8;
   absval = 1;
end
if nargin == 3
    absval = 1;
end
% Find dimensions
sizex = size(x);
sizey = size(y);
if ~isequal(sizex,sizey)
    error('Images must have equal dimensions.')
end
% Number of bands
nb = size(x,3);
% Preallocate mean bs
bs = zeros(nb,1);
if nargout == 3
    % Preallocate bmaps (memory voracious)
    bmaps = single(zeros(sizex));
    for b = 1:nb
        [bs(b), bmaps(:,:,b)] = bias_fs( x(:,:,b),y(:,:,b),ws,absval );
    end
else
    for b = 1:nb
        bs(b) = bias_fs( x(:,:,b),y(:,:,b),ws,absval );
    end
end
% Average quality 
bm = mean(bs);

end