Properties of SIFT
Extraordinarily robust matching technique
•Can handle changes in viewpoint
–Up to about 60 degree out of plane rotation
•Can handle significant changes in illumination
–Sometimes even day vs. night (below)
•Fast and efficient—can run in real time
•Lots of code available
–http://people.csail.mit.edu/albert/ladypack/wiki/index.php/Known_implementations_of_SIFT 
http://www.cs.washington.edu/homes/snavely/outgoing/test/1a.jpg http://www.cs.washington.edu/homes/snavely/outgoing/test/2a.jpg