S.L.A.M — Tracking for MR
S.L.A.M. is an acronym used in the mixed reality community that refers to the tracking systems that are utilized in order to create one to one positional translation between the real and virtual worlds.
S.L.A.M stands for Simultaneous Localization And Mapping. SLAM to the layman is a system that allows your computer to see whats around it. Weird, right?
Your computer makes sense of visual world by employing the use of points or coordinates. It marks 3D items with these points. Then through either a process of triangulation or trilateration, it maps these points as their positions shift relative to one another, in real time. This concept of real time graphics processing is where Simultaneous comes from in the SLAM acronym. It is important that the information from the various sensors is measured in unison, or if they are not in unison, that this time difference or, latency, is accounted for and adjusted as necessary.
Local Coordinate Systems, opposed to a global coordinate systems, are comprised of coordinates in your immediate environment marking stuff like the door frame, the desk , and flooring in the image to the left. In order to achieve 6DOF (Degrees Of Freedom), there are sensors in the HMD (Head Mounted Display) and depending on your application, on the hands, elbows, knees, and feet, which then allow the computer to record the pose of the viewers field of view as well as their bodies’ position in the space. This record or Map, is referenced and updated each time the sensors and camera brings in new information to the GPU.
When these two tracking systems come together simultaneously, it allows for a simple one to one translation of player position in both the Real and Virtual worlds.
https://venturebeat.com/2017/07/31/how-slam-technology-is-redrawing-augmented-realitys-battle-lines/
