Speech Enhancement Using Beamforming and Kalman Filter for In-Car Noisy Environment

The effectiveness of the communication system gets seriously degraded in car by noises like engine sounds and ambient noise, thus decreasing the quality of speech. In modern cars, a lot of effort is put on reducing the background noise. In this paper, speech enhancement cascaded scheme named BEAM-KAL is developed to get the better intelligibility and quality of speech. For this, multichannel beamforming techniques are combined with single channel Kalman filter to get better quality of speech signals which suffer in-car noises. In beamforming, microphone arrays are used to extract the speech signal of interest from a specific desired direction, whereas signals contaminated with noises from various directions are attenuated. However, this technique does not appear to provide enough improvement by itself. Hence, the Kalman filter has been used for its further enhancement. Experiments are performed with real recordings taken while driving in a noisy automobile environment. The performance is investigated with SNR, PESQ and spectrograms and has been shown to produce a better quality of speech.