Steerable Differential Polynomial Beamforming

Abstract

Conventional steerable differential beamformers are usually only applicable to microphone arrays with regular planar geometries. Recent years have seen the interest in the design of steerable differential beamformers for microphone arrays with an arbitrary planar geometry. However, the existing steerable differential beamformers for arbitrary planar arrays need to repeatedly recalculate their beamformer weight vectors when the steering angle changes, which may affect their real-time implementation. In this paper, we propose a steerable differential polynomial (SDP) beamformer design approach based on the Farrow structures by using the Jacobi-Anger expansion and least-squares method. The SDP beamformers are applicable to arbitrary planar microphone arrays, and can realize continuous 360-degree mainlobe steering in real time without the need of updating beamformer weight vector, which is very useful for time-critical applications such as hearing assisting devices. Simulation results are also reported to demonstrate the effectiveness of the proposed SDP beamformers.