title: PSNR and int16 data type images
body: <p>is this code right for calculating PSNR for int16 data types images?</p>
  
  <pre><code>function PSNR = PeakSignaltoNoiseRatio(origImg, distImg)
  
  [M N] = size(origImg);
  error = origImg - distImg;
  MSE = sum(sum(error.^2)) / (M * N);
  PSNR=10*log10(255*255/MSE);
  </code></pre>