Compensating for distance compression in virtual audiovisual environments

Virtual environments are increasingly being used for various applications. In recent times, with the advent of consumer grade systems, virtual reality has reached a critical mass and has exploded in terms of application domains. Extending from games and entertainment, VR is also applied in military training, remote surgery, flight simulation, co-operative work, and education. While all of these applications require careful design with respect to the interaction and aesthetics of the environment, they differ in their requirement of veridical realism: the impression of suspending disbelief to the point where perception in the environment is equal to the real world. At the same time, research in human centred disciplines have shown predictable biases and `errors' in perception with respect to the environment intended by the designer. This can be a challenge when certain perceptual phenomena prohibit the applicability of VR due to a discontinuation in what is rendered and what is actually perceived by the observer. This thesis is focused on a specific perceptual phenomenon in VR, namely that of distance compression, a term describing the widespread underestimation of distances that occur in VR relative to the real world. This perceptual anomaly occurs not only in visual based virtual environments, as compression has been observed and studied in auditory only and audiovisual spaces too. The contribution of this thesis is a novel technique for reducing compression, and its effectiveness is demonstrated in a series of empirical evaluations. First, research questions are synthesized from existing literature and the problem is introduced and explained through rigorous review of previous literature in the context of spatial audio, virtual reality technology, psychophysics, and multi-sensory integration. Second, the technique for reducing distance compression is proposed from an extensive literature review. Third, the technique is empirically tested through a series of studies involving human participants, virtual reality hardware, and bespoke software engineered for each study. Finally, the results from the studies are discussed and concluded with respect to the research questions proposed.