On the noisereduction performance of the MVDR beamformer innoisy and reverberant environments

Abstract

The minimum variance distortionless response (MVDR) beam-former has been widely studied for extraction of desired speech signals in noisy acoustic environments. The performance of this beam-former, however, depends on many factors such as the array geometry, the source incidence angle, the noise field characteristics, the reverberation conditions, etc. In this paper, we study the performance of the MVDR beamformer in different noise and reverberation conditions with a linear microphone array. Using the gain in signal-to-noise ratio (SNR) as the performance metric, we show that the optimal performance of the MVDR beamformer generally occurs when the source is in the endfire directions in different types of noise, which indicates that, as long as a linear array is used, we should configure it in such a way that the endfire direction is pointed to the desired source. Simulations in reverberant environments also verified this result, though the performance difference between end-fire and broadside directions reduces as the degree of reverberation increases.