Active speech source localization by a dual coarse-to-fine search

Accurate and fast localization of multiple speech sound sources is a significant problem in videoconferencing systems. Based on the observation that the wavelengths of the sound from a speech source are comparable to the dimensions of the space being searched, and that the source is broadband, we develop an efficient search strategy that finds the source(s) in a given space. The search is made efficient by using coarse-to-fine strategies in both space and frequency. The algorithm is shown to be robust compared to typical delay-based estimators and fast enough for real-time implementation. Its performance can be further improved by using constraints from computer vision.