title: Why we shift zero-frequency component to center of spectrum of an image?
body: <pre><code>F = round(fftshift(abs(fft2(A))))
  </code></pre>
  
  <p>where A is the image.</p>
  
  <p>I am studying contrast stretching in Digital Image Processing. I don't understand zero frequency component. I searched for it but I couldn't understand it, kindly refer some documentation about zero frequency component.</p>