title: JPEG artifacts detection
body: <p>Are there known algorithms that can detect image degradation programatically without looking at the image?</p>
  
  <p>I think about obvious (visible) image artifacts of lossy re-encoding, like color
  distorsion, edge noise, blockness etc.<br>
  For example, images encoded from original source with JPEG quality 80 are fine.</p>
  
  <p><em>I hope this is right place to ask, but if moderators think that I should have asked at DSP stackexange or similar, please relink.</em></p>