SLAM
From Virtual Reality, Augmented Reality Wiki
SLAM (Simultaneous Localization And Mapping) is a method of inside-out 3D tracking based on optical data of an environment that does not require any additional hardware other than the device being tracked. It is similar to visual inertial odometry (VIO).
One method of SLAM is ORB_SLAM2. Another method is ORB_SLAM3. Another SLAM-like method is RTAB-Map.
The Hololens 1 and the Magic Leap 1 both use a SLAM-type system for their 3D tracking.
The Oculus Quest 2 uses a tracking system that is some variant of SLAM or VIO.
