Binaural Distance Perception Based on Direct-to-reverberant Energy Ratio

The direct-to-reverberant energy ratio has long been recognized as an absolute auditory cue for sound source distance perception in listeners. Traditional methods to extract this energy ratio are based on post-processing of the estimated room impulse response, which is computationally expensive and inaccurate in practice. An alternative is based on estimating the energy arriving from the azimuth of the direct source, under the assumption that reverberant components result in a spatially-diffuse sound field. We propose a binaural equalization-cancellation technique to calculate this energy ratio by locating the source in a delay-line structure, and go on to demonstrate its potential as a distance cue for both simulated and real data. The system is integrated with a Bayesian inference framework, particle filtering, to handle the nonstationary of energy-based measurements. Experiments on simulated room data showed the resulting computational model is capable of estimating source distance based on reverberation information.