Phase correlation to detect translation between 2 images

Hi everybody,

I am desperately trying to use the phase correlation method to detect a translation between two images. Besides all the previous posts about phase correlation, I cannot make it work.

I have tried the following code for a simple 1D signal. The translation between x1 and x2 should be 50 "pixels", but it gives me 1.

Any help would be very much appreciated.

t = 0:0.005:1;
x = [sin(pi*t) zeros(1,20) -0.5*sin(pi*t)];
x1 = x(1:end-50);
x2 = x(51:end);

win = hamming(length(x1))';
x1 = win.*x1;
x2 = win.*x2;

x1fft = fft(x1);
x2fft = fft(x2);
R = x1fft.*conj(x2fft);
R = R./abs(R);
r = ifft(R);
shift = find((r == max(r)))