Positional tracking
Position and orientation tracking (PnO tracking) is tracking of an object's position and orientation (PnO) in space. It can be used to track display headsets and handheld input devices. It is also known as 6DOF tracking, for the 6 degrees of freedom (DOF), which are ways that an object can move: horizontally, vertically, depthwise, and three rotation movements: pitch, roll, and yaw.
It can be done using a number of different hardware technologies, such as electromagnetic tracking or camera-based tracking. Methods of camera-based tracking include methods using SLAM or VIO. PnO tracking is related to rotation tracking, which uses 3DOF of space.
It is used in devices like the Meta Quest 2. It is used in an absolute positioning system. Position can be represented in a computer system using a 3D vector. Rotation can be represented using a quaternion.
It can be done in theory using multilateration using lasers.[1]
Methods
- Markerless inside-out tracking, which is camera-based tracking (SLAM/VIO)- This is used on headsets such as Meta Quest headsets and the Project North Star. An open source method is Basalt. It can use visible light or infrared light, which can be artificially emitted.
- Marker-based tracking - Camera based tracking that uses markers in the environment, which is simpler to implement.
- Electromagnetic tracking.[2] Electromagnetic tracking requires an external source. It gets jittery when there is metal around, like a metal laptop computer. Magnetic tracking is typically wired, but it does not have to be.
- UWB tracking
- Mechanical tracking[2]
- Acoustic tracking[2]
- Visible light-based tracking
- Infra-red based tracking
Magnetic tracking
240Hz is generally sufficient if using magnetic tracking with no filtering.
History
3D tracking has been used for motion capture for 3D animated movies.
The 3DOF regime of cheap tracking was embraced by Oculus VR with the original Oculus Rift. The CV1 of the Oculus Rift used (and the DK2) constellation tracking, which is a complex method of 6DOF tracking added on to a robust 3DOF system.
References
- ↑ Nitsche, Jan; Franke, Matthias; Haverkamp, Nils; Heißelmann, Daniel (2021-02-19). "Six-degree-of-freedom pose estimation with µm/µrad accuracy based on laser multilateration". Journal of Sensors and Sensor Systems (Copernicus GmbH) 10 (1): 19–24. doi:10.5194/jsss-10-19-2021. ISSN 2194-878X.
- ↑ 2.0 2.1 2.2 3D User Interfaces: Theory and Practice, 1st edition, page 97