Dynamic signal combining for distributed microphone systems in car environments

Abstract

Distributed microphone systems in cars usually provide dedicated microphones for several speakers where each microphone captures the desired speech signal at the best. The signal quality may differ strongly among the speaker channels depending on the microphone position, the microphone type, the kind of background noise, and the speaker himself. When combining these signals to a weighted mix annoying switching artifacts may result. In this contribution a new dynamic signal mixer is presented that uses spectral preprocessing to compensate both for different speech signal levels and for different background noise levels and colorations. Thus, artifacts are avoided and smooth transitions can be achieved for the various speech level and the background noise spectrum at speaker changes.