Okay, now for the coding. I’m assuming you know how SIFT works (if not, check SIFT: Scale Invariant Feature Transform. It’s a series of posts on the SIFT algorithm). I’ll be using C++ and classes to keep things neat and object oriented.OpenCV doesn’t come with inbuilt functions for SIFT, so we’ll be creating our own functions. My code here is based on code by Jun Liu. He implemented SIFT with VXL