Related to #4.
Benchmarking quality and time performance:
- DBoW2 vs. FBoW (In addition, other methods)
- Sampling methods for feature points (Relationship between Tracking.max_num_keypoints and Quality)
ref. Eric Nowak, Frédéric Jurie, and Bill Triggs, Sampling Strategies for Bag-of-Features Image Classification, ECCV 2006.