function q = dummy(a,b)

% motion from fft2       2-D version
% fast conv; see how much image is shifted over
% motion_estimation by fft methods: cross spectrum, CROSS SPECTRUM
%
% Example use: q=motion_fft2(a,b)
%
% See also est_trans_fft2
% (e.g. you probably want to use est_trans_fft2 and not this)

A = fft2(a);
B = fft2(b);
%%%%B = fft2(rev(b));   % conj doesnt work quite right in 2D
                        % the phase shift seems to have effect???
                        % but this should not be a problem
% conj is like reversal in time domain
% Q = conj(B).*A./sqrt(A.*conj(A).*B.*conj(B));
Q = conj(B).*A./(abs(A).*abs(B));
q = ifft2(Q);     % q should be real (e.g. imag part should be nearly 0)

%dispmatb(log(real(q+max2(q)/1000000)))  % display as log image