Non-field-of-view indoor sound source localization based on reflection and diffraction

This paper presents a new acoustic approach to locate a mobile target outside the field-of-view (FOV), or the non-field-of-view (NFOV) of an optical sensor, based on the reflection and diffraction signals. In this approach, a sensor platform determines a reflection time-difference-of-arrival (TDOA) and frequency dependent diffraction to two distinct observation likelihoods from a single target´s sound. The fusion of these likelihoods, a joint acoustic observation likelihood, estimate the NFOV target probabilistically within the recursive Bayesian estimation (RBE) framework. The approach was formulated and derived mathematically. Through parametric studies in simulation, the potential of the proposed approach for practical implementation has been demonstrated by the successful localization of the sound source. Finally, a preliminary validation of sound separation was performed in a controlled experimental environment showing the difference between diffraction alone and combination of diffraction and reflection signals.