Miikka Tikander

Binaural positioning system for wearable augmented reality audio

Microphone arrays have been traditionally used for locating sound sources. In this scenario, the array is assumed to be static and the sound sources may be static or moving. If, on the other hand, the sound source or sources are assumed to be static and a user is wearing a microphone array, the exact position and orientation of the user can be solved. We propose a method for binaural positioning of a user based on binaural microphones and known external anchor sources placed in the environment of a user. We demonstrate that a users location and orientation can be tracked, in many cases very accurately even if the anchor sound is at a low level and there are distracting sources in the environment.

Head-tracking and subject positioning using binaural headset microphones and common modulation anchor sources

A prerequisite in many systems for virtual and augmented reality audio is the tracking of a subjects head position and direction. When the subject is wearing binaural headset microphones, the signals from them can be cross-correlated with known sound sources, called here anchor sources, to obtain an accurate estimate of the subjects position and orientation. In this paper we propose a method where the anchor sources radiate in separate frequency bands but with common modulation signal. After demodulation, distance estimates between anchor sources and binaural microphones are obtained from positions of cross-correlation maxima, which further yield the desired head coordinates. A particularly attractive case is to use high carrier frequencies where disturbing environment noise is lower and sensitivity of hearing to detect annoying anchor sources is also lower.