Head tracking
Head tracking is the use of 3D tracking for getting the position and orientation of a user's head and inputting it into a computer. It is done to generate the view of a rendered scene for real-time 3D graphics, typically for a head-mounted display.
One of simplest types is mechanical head tracking.
The goal of head tracking is to get an absolute position and orientation relative to a reference frame, like a room, desk, or outdoor space.
Head tracking was largely originally developed for military use.
Orientation can be determined using an IMU+magnetometer combination chip like chips from STMicroelectronics, which senses the earth's magnetic field.
Examples[edit]
- The Magic Leap 1 used cameras and visual-inertial odometry (VIO).
- The HoloLens 1 and 2 used cameras and VIO.
- The North Star, which typically uses an Intel T265, uses SLAM/VIO.
- The Virtual Research V8 can be used with a HiBall tracker.
- The Oculus Rift DK2 uses camera-based tracking.
History[edit]
Head tracking was developed for military use.
The prototype of head tracking was done using a hand-steered periscope system for aiming weapons, such as with the P-4 gunsight computer from Sperry.
The operational mode of the Sperry computing gunsight was adapted from hands to head, where the mechanical handgrips and periscope tracking was replaced by a linkage directly to the user's head.
Non-mechanical head tracking was developed for fighter jet pilots' head mounted sight systems, for example, VTAS.
In the 1970s, an approach by Polhemus used SPASYN. A Raytheon device used light-emitting diodes on the helmet and cockpit-mounted photo diode detection surfaces. A Honeywell technique used ultrasonic sound ranging and sensing.[1]
Rotation-only[edit]
Rotation-only head tracking was done in the headsight in about 1961.
Rotation-only 3DOF head tracking was done in the Sutherland head-mounted display.
Mechanical linkages have been used to track helmet position in military applications.[2]
One of the earliest (1970s) sighting HMD systems to be fielded was the mechanical linkage headtracked sight used to direct the fire of the gimbaled gun in the U.S. Army’s AH-1G Huey Cobra attack helicopter.[3]
Position and rotation[edit]
The first 6DOF head tracking systems were developed by Polhemus and called SPASYN. This technology was used in the Visually Coupled Airborne Systems Simulator.
Military development[edit]
Before 1972, the U.S. Army used a mechanically-coupled helmet sight built by Sperry in armed helicopters.
Non-mechanical systems were developed for the purpose of ejection seats.
In early 1972, VTAS started going into operational Navy aircraft after nearly a decade of development and evaluation.[4][5]
VTAS was implemented in the Army/Lockheed AH-56A Cheyenne helicopter.
In about 1972, the U.S. Air Force's Aero-Medical Laboratory sought simpler, lower—cost techniques than VTAS and awarded three six-month study contracts to explore alternative concepts. The three contractors were Honeywell, which was to explore use of ultrasonic sensors, Polhemus, which was to investigate magnetic tracking, and Raytheon, which was to study optical sensor techniques.[4][5]
References[edit]
- ↑ "Visually Coupled Systems". 1973-07-03. http://www.best-of-flightgear.dk/vtasaur.htm.
- ↑ "File:Helmet-Mounted Display Design Guide.pdf". 2026-08-01. https://www.xvrwiki.org/wiki/File:Helmet-Mounted_Display_Design_Guide.pdf.
- ↑ "Introduction to Helmet-Mounted Displays". https://usaarl.health.mil/assets/docs/hmds/Section-9-Chapter-3-Introduction-to-Helmet-Mounted-Displays.pdf. "sighting HMD systems to be fielded was the electro-mechanical linkage"
- ↑ 4.0 4.1 Gubler, Abraham (2012-11-26). "VTAS, Soviet and South African early HMS development". Secret Projects Forum. https://www.secretprojects.co.uk/threads/vtas-soviet-and-south-african-early-hms-development.17663/.
- ↑ 5.0 5.1 Aviation Week January 31 1972