https://www.youtube.com/watch?v=iGZpJZhqEME
Lecture 17: Bag of words

https://youtu.be/iGZpJZhqEME?t=16m10s

16:12 -->

Descriptor for each interest point. High dimensional space. Cluster them, and this is our vocabulary.

English language has a vocabulary [since] 1000s of years, visual language we don't have a vocabulary so we have to come up with our own vocabulary.