fname = input('\nEnter filename (without extension)\n');
format = input('\nEnter image format extension\n');
A = imread(fname,format);           % Load the file
figure();                           % New figure window for image
colormap('gray');                   % Change to grayscale
imagesc(A);                         % Show image
figure();                           % New figure window for spectrum
Y = fft2(double(A));                % Compute image spectrum
Z = log(abs(fftshift(Y)));          % Put origin in center.  Use log plot!
Z2 = uint8(Z/max(max(Z))*255);      % Normalize to maximum value in order
                                    % to get best "picture" of spectrum
colormap('gray')                    % Change to grayscale
imagesc(Z2);                        % Show normalized image spectrum