%% dft2demo2
%% show image and log of shifted |DFT|

% get image
%load mandrill
 load earth
%X = zeros(128,128); X(61:80,41:80)=1;

% get and shift 2D FFT of image
FX = fft2(X); 
sFX = fftshift(FX);

% display results 
figure(1)
imagesc(X), colormap(gray)
title('original image');

figure(2)
imagesc(log(1+abs(FX))), colormap(gray)
title('log(1+|dft|)');

figure(3)
imagesc(log(1+abs(sFX))), colormap(gray)
title('shifted log(1+|dft|)');