title: SIFT- how to find similarity in more than 2 images
body: <p>I know how to compare 2 images with SIFT (in matlab) but what if I have to find the similarity in between multiple images. Let for instance, I have 30 Images. How can I use SIFT to say that 10 of them have 30% match and 5 of them have 95% match? 
  I can use clustering but before doing that I need some kind of value on which I can apply clustering technique.
  I have been bothered by this question for quiet a few hours. So friends if you know please do help me.</p>
  
  <p>thanks</p>