Co-Visibility Graph

Apparently they use this in ORB-SLAM 2. The SLAM textbook talks about this.

This seems to be the original paper that introduced this idea:

• Double window optimisation for constant time visual SLAM
  • available locally here

This paper talks about the many ways that are leveraged to have BA run in real-time:

• Active Window
  • taking a subset of the last $K$ windows
• Relative representation
• Pose-pose reduction (Pose Graph Optimization)

Co-visibility refers to those features that are observed together with the current keyframe). Therefore, in BA optimization, we take some keyframes and landmarks in the co-visibility graph to optimize.