Microphone array signal processing: beyond the beamformer

Array signal processing is a well-established area of research, spanning from phased array antennas in the middle of the last century to hands-free audio in recent years. As devices incorporating microphone arrays begin to appear in the home, new practical challenges are presented to well-known signal processing problems such as source localization and beamforming. In this talk, we consider some new algorithms that use multichannel observations outside the common beamforming paradigm. These include dereverberation using spatiotemporal averaging, acoustic channel shortening and the acoustic Rake receiver, with relevant audio examples. We also investigate the problem of localizing reflecting boundaries in an acoustic space by considering the time of arrival of 1st-order reflections. Such algorithms are expected not to replace but to compliment beamforming in new and robust future applications.