Accurate and fast Six Degree of Freedom position tracking is a crucial function for all VR/AR headsets. Inertial sensors alone are insufficient to give a repeatable absolute position, so optical techniques are typically used. There are two key approaches.
Inside Out tracking uses cameras on the device to track multiple fixed features identified in the surrounding scene. By tracking the relative movement of the features, from multiple camera positions, the 6DoF position of the device can be calculated using image processing. Because no additional infrastructure in the scene is required, this approach is now the most widely used.
Outside In tracking places fixed sensors, typically cameras, around the room in which the device(s) are used. Specific markers are placed onto the devices to be tracked, typically infrared LEDs. By tracking the relative movement of the markers from different camera positions, high accuracy position can be triangulated. Whilst this approach high reliability and accuracy, the requirement to place hardware around the room means that it is used only for more specialized systems.
ams OSRAM offers sensors and emitters for all types of position tracking systems:
- MIRA global shutter image sensors and wafer level optics can be combined to create ultra-small, IR enhanced, low power camera modules with resolutions from 0.16 – 2.2MP.
- Firefly IR chip LEDs provide a high efficiency IR point source in a small form factor, idea for use as a marker on objects to be tracked.
- BPW34S and SFH2704 photodiodes