Broadband beamforming optimization for speech enhancement in noisy environments

Abstract

We have developed a method to optimize the directional sensitivity of a filter-and-sum beamformer. The directivity of the broadband microphone array is optimized by adjusting the spatial transducer positions and the impulse response of the beamformer. We focus on the optimization of 1-dimensional arrays consisting of M omnidirectional microphones and M FIR filters each of length L. The signal sources are assumed to be point sources evenly distributed over a sphere of radius r or over a set of concentric spheres. The target beam pattern for optimization is defined in terms of the desired source signal directions (mainlobe) and the angles for background noise attenuation.