Some current challenges in multichannel acoustic signal processing

Abstract

Hands-free human/machine communication involves major challenges for today’s state of the art signal processing if the humans should not be forced to carry or wear any technical gear and should be free to move. The spatial domain sampled by multiple loudspeakers for reproduction and multiple microphones for signal acquisition allows for spatialized listening experiences and for spatially selective acoustic scene analysis, respectively. Along with the possibility to serve several human communication partners simultaneously, such systems also introduce the need for localization algorithms. Three main types of impairment have to be addressed by signal processing algorithms to fulfill the promises of the general concept: first, acoustic feedback from the loudspeakers into the microphones; second, ambient noise and undesired pointlike interferers; and, finally, echoes and reverberation as picked up by the human ear when listening to the loudspeaker signals or as recorded by the microphones that actually should record only the direct-path component of the source signal. Accordingly, some of the current challenges in multichannel acoustic echo cancellation, in spatially selective noise and interference suppression, in source separation and localization, and in dereverberation are investigated.