Binaural technology for virtual reality

The use of nonintrusive virtual environments is gaining more and more importance but was focused mainly on addressing the visual sense. However, the human perception consists not only of visual input and thus it would be worthwhile to create multimodal and interactive virtual environments. This thesis describes the techniques required to include the acoustic component into virtual environments and the implementation of a software system, which creates complex artificial acoustical scenes in real time. The system is based on the binaural technology. It features spatially distributed sound sources, which are utilized to create an environment that is as authentic as possible. This comprises a description of the source, including its relevant angle-, distance-, and time-dependent radiation, the sound distribution in the virtual scene, the perception-related consideration of all sound field components, and the exact reproduction at the ears of the user. In this context, an approach for dynamic crosstalk cancellation is presented, which enables a loudspeaker-based reproduction. The required filters are processed in real time on the basis of the position data and measured transfer functions of the outer ear. Furthermore the integration of this spatial audio system into a five-sided Virtual Reality display system is described and evaluated.