Sound Source Localization Based on Approximation of Sinc Function by FIR Filter
Kazuki Fujita, Kenji Suyama · IEEJ Transactions on Electronics Information and Systems · 2024
Sound source localization is carried out based on TDOA (Time-Difference-Of-Arrival) between microphones. When the TDOA is detected from a phase difference between two microphones, an ambiguity of phase difference often occurs under a high resolution situation and thus the estimation accuracy degrades significantly. In this paper, a propagation delay characteristic is approximated directly using FIR (Finite Impulse Response) filter, in which an impulse response is described by sinc function and an adjustable parameter is just a TDOA. Although there is not the ambiguity of phase difference in this procedure, an appropriate TDOA has to be searched using any optimization because the TDOA takes a real value. This falls into a non-linear optimization problem and there are many local minima in the search space therefore, a local minimum stagnation often occurs when applying a normal steepest decent algorithm for the search. In the proposed method, TDOA is estimated by introduction an avoidance method of local minimum stagnation. The validity of the proposed method is shown from several experimental results.