Speech enhancement using multi-reference noise reduction in a vehicle environment

This paper presents a multi-reference noise reduction system for use in a vehicle. It is aimed at enhancing the driver’s speech in noisy driving environments for applications such as voice commands or hands free phone. First, our system objective is briefly presented as well as the problems of classical techniques, like Beamforming, may face in such a harsh environment as a vehicle cabin. Second, a brief analysis of noises aboard a road vehicle is done. Third, the noise reduction architecture comprising a linear and non linear block with two respective non acoustic noise references is presented. Finally, some results obtained in real driving conditions are presented and analysed. Both human listening tests and speech recognition tests prove our system increases global performances compared to what is obtained with classical single channel speech processing methods.