%   Phase Correlation
%   2/09
%   HE

close all;
im=imread('VIS_0109.bmp');
im1=double(im(1:200,1:300,1))+25*randn(200,300);
im2=double(im(20:219,5:304,3))+25*randn(200,300);
[x,y]=size(im1);

subplot(2,2,1); imagesc(im1); colormap(gray); grid; title('R Color (Noise mean=0, std=20)');
subplot(2,2,2); imagesc(im2); colormap(gray); grid; title('B Color (Noise mean=0, std=20)');

Ga=fftshift(fft2(im1));
Gb=fftshift(fft2(im2));
R=(Ga.*conj(Gb))./abs(Ga.*conj(Gb)); Normalized power spectrum
%R=Ga.*conj(Gb);
r=abs(fftshift(ifft2(R)));
[mx,col]=max(max(r));
[mx,row]=max(max(r'));
dx=row-x/2-1
dy=col-y/2-1
subplot(2,2,3); mesh((r)); title('Correlation function');
subplot(2,2,4); imagesc(circshift(im2,[dx,dy]));
colormap(gray); grid; title('B Color corrected for translation errors');