Real-Time Implementation of an Adaptive Beamformer-Postfilter System for Seat belt Microphones on SHARC ADSP-21489
* Presenting author
Belt Microphones are an elegant and interesting alternative to conventional microphones used for speech communications in automobile environments. Three microphones are integrated into safety belts of the car, which are placed around the shoulder and chest of the passenger after fastening the belt. Belt microphones offer an improved SNR (signal-to-noise ratio) due to small distance to the passenger’s mouth compared to common microphone positions. State-of-the-art systems select only the microphone with the highest SNR on the belt as an input to speech enhancement schemes. The performance can be further improved by combining all belt microphones to generate an enhanced output. However, belt microphones come with their own inherent challenges. Even a slight bodily movement results in significant change in the position of microphones on the belt. Another problem is when the microphones are accidentally touched by fingers or clothing such as jacket zips, ties. Taking these unique challenges into account, this contribution proposes a low-complexity and robust adaptive beamformer-postfilter system with special focus on its real-time implementation on a SHARC ADSP-21489 hardware. The system’s overall performance designed for belt microphones is then evaluated and compared with the single best belt microphone in terms of SNR and SIR (signal-to-interference ratio).