Efficient Continuous Beam Steering for Planar Arrays of Differential Microphones

Abstract

Performing continuous beam steering, from planar arrays of high-order differential microphones, is not trivial. The main problem is that shape-preserving beams can be steered only in a finite set of privileged directions, which depend on the position and the number of physical microphones. In this letter, we propose a simple and computationally inexpensive method for alleviating this problem using planar microphone arrays. Given two identical reference beams pointing in two different directions, we show how to build a beam of nearly constant shape, which can be continuously steered between such two directions. The proposed method, unlike the diffused steering approaches based on linear combinations of eigenbeams (spherical harmonics), is applicable to planar arrays also if we deal with beams characterized by high-order polar patterns. Using the coefficients of the Fourier series of the polar patterns, we also show how to find a trade-off between shape invariance of the steered beam, and maximum angular displacement between the two reference beams. We show the effectiveness of the proposed method through the analysis of models based on first, second and third-order differential microphones.

Advances in Wave Digital Modeling of Linear and Nonlinear Systems: A Summary

“…As a secondary research project during my Ph.D., I worked on the modeling of Differential Microphone Arrays (DMAs) [2,3,17,22]. In this regard, Chap.…”

Arrays of First-Order Steerable Differential Microphones

“…In the recent years, several research works focused on the development of strategies for the design of small-size Differential Microphone Arrays (DMAs) [1][2][3][4][5][6][7][8] because of their nearly frequencyinvariant beampattern, good directivity properties and low computational cost. Spatial responses of DMAs can be designed to match beampatterns of arbitrary order, even though low-order (especially first-order) DMAs are usually preferred in practice [1,2,9,10].…”

Sound Source Localization and Reconstruction Using a Wearable Microphone Array and Inertial Sensors

“…While not matching the form factor of hearing aids, such as binaural behind-the-ear devices, the AF is rather an idealized platform with extended capabilities. Some of these are: high-dimensional beamforming; DOA estimation in absolute coordinates; continuous beam-steering [19] with source location feedback; and easier application of experiments in ecologically valid scenarios due to its portability. Simulation and experimental results demonstrate source localization and reconstruction using the Taylor series expansion method in scenarios with single and multiple sources, and rotating AF.…”