Acoustic 3D tracking system
An acoustic tracking system is a system that tracks the position or orientation of an object using sound or ultrasonic sound, in acoustic tracking.
It may do multilateration depending on the kind of the system.
An ultrasonic tracking system is a 3D tracking system that uses ultrasonic sound. It may do multilateration. It may use the Kabsch algorithm to do point-set registration.
It may be used, for example, in an augmented reality glasses system to track the position and orientation of the glasses.
It needs a line of sight (auditory sight), which is a line of unimpeded travel between source and sensor.
Ivan Sutherland's report on the ultrasonic positioning system used with his 3D display did not mention any use of the Kabsch algorithm.[1]
Acoustic tracking can be done using multilateration. However, the speed of sound is not constant; it changes with temperature, humidity, and air pressure, which is the biggest soruce of error in acoustic ToF systems.
Examples[edit]
Technology[edit]
Ultrasonic tracking uses high-frequency sound emitted from source components and received by microphones and software to detect the position of objects.[2] It uses ultrasound. It can be used to either track the position of an object, or its full position and orientation.
There are two explored classes of methods of acoustic tracking. One is to measure time-of-flight of the sound from the transmitter(s) to the receivers, performing multilateration. Another is to measure the phase coherence of the sound.[3] It is called phase coherent ultrasonic tracking.
Ultrasonic tracking requires "line of sight" but for sound. It can be done in a very small form factor.
It can use MEMS ultrasonic transducers.[4]
It can be used in a pen form factor.
Ultrasonic tracking was used by Ivan Sutherland's head-mounted display.
Phase coherent tracking was used by Ivan Sutherland in his head mounted three-dimensional display.[5]
Time-of-flight based[edit]
Examples of time-of-flight trackers are the Logitech 6DOF ultrasonic head tracker and the Fly mouse.[5]
For something like a pen, 5DOF tracking can be used, where a pen as two transceivers total: one at each end. In a 3D system where the user is only on one side, three counterpart transceivers can be used to sense the two transceivers from the pen. The full position of the pen is tracked, except for twisting the pen about its axis.
Construction[edit]
Acoustic tracking systems may use sets of at least three ultrasonic sensors and at least three ultrasonic transmitters on devices in order to calculate the position and orientation of an object such as a handheld controller.[3]
Examples[edit]
An iteration of the Pico Neo headset uses ultrasonic tracking for its controller.[6]
References[edit]
- ↑ Sutherland, Ivan E. (1968). "A head-mounted three dimensional display". ACM Press. p. 757. doi:10.1145/1476589.1476686.
- ↑ 3D User Interfaces: Theory and Practice, page 98
- ↑ 3.0 3.1 "Pose tracking". 2017-04-11. https://en.wikipedia.org/wiki/Pose_tracking.
- ↑ "A New Tracking Technology in 3D space". 2024-07-31. https://article.murata.com/en-eu/article/new-tracking-technology-and-use-in-3D-interaction.
- ↑ 5.0 5.1 Mazuryk, Tomasz; Gervautz, Michael (1999-12-30). "History, Applications, Technology and Future". https://www.researchgate.net/publication/2617390_Virtual_Reality_-_History_Applications_Technology_and_Future.
- ↑ Hayden, Scott (2017-12-26). "Pico's New 6DoF Standalone VR Headset is Coming Westward, Including 6DoF Controllers". https://www.roadtovr.com/picos-new-6dof-standalone-vr-headset-coming-westward-including-6dof-controllers/.
- ↑ Medina, Carlos; Segura, José; De la Torre, Ángel (2013-03-13). "Ultrasound Indoor Positioning System Based on a Low-Power Wireless Sensor Network Providing Sub-Centimeter Accuracy". Sensors (MDPI AG) 13 (3): 3501–3526. doi:10.3390/s130303501. ISSN 1424-8220.