figure(1)
clf
a = imread('PSWebImageBitMap0001.bmp',  'bmp');
b = a(:,:,2);
imagesc(b);
colormap(gray)

figure(2)
clf
c = fft2(b);
imagesc(abs(fftshift(c)));
colormap(gray)

figure(3)
clf
d = ifft2(c);
imagesc(abs(d));
colormap(gray)

