Using ORB features to build out ORB-SLAM.
ORB = Oriented FAST Rotated BRIEF
https://ieeexplore.ieee.org/document/6126544 Available locally file:///Users/stevengong/My%20Drive/Books/ORB_An_efficient_alternative_to_SIFT_or_SURF.pdf
ORB is the combination of oFAST (for key points) and rBRIEF (for descriptors).
- You should first understand what a Feature Point is
1. oFast (Oriented FAST)
“FAST features are widely used because of their computational properties. However, FAST features do not have an orientation component. In this section we add an efficiently computed orientation.”
- So FAST Keypoint cannot detect orientation. oFast adds on to that
The 2 improvements
- Include orientation information using the intensity centroid (more below)
- Include scale information using Image Pyramids
Summarized from the Visual SLAM book, though you should also reference the original paper
- In a small image block , define the moment of the image block as: