X=imread('cameraman.tif');
subplot(2,2,1)
imshow(X,map);
fftI=fft2(X);
A=abs(fftI);
A=[(A-min(min(A)))/(max(max(A))-min(min(A)))]*255;
subplot(2,2,3)
imshow(A);
sfftI=fftshift(fftI);
B=abs(sfftI);
B=[(B-min(min(B)))/(max(max(B))-min(min(B)))]*255;
subplot(2,2,4)
imshow(B);