Spherical Reverse Beamforming for Sound Source Localization Based on the Inverse Method.

Chao Sun,Yuechan Liu

doi:10.3390/s19112618

Abstract

A spherical array is not limited to providing an acoustic map in all directions by the azimuth of the array. In this paper, spherical reverse beamforming for sound source localization based on spherical harmonic beamforming and the principle of sound field reconstruction is proposed in order to output a sharper scanning beam. It is assumed that there is an imaginary sound source at each scan point, and the acoustic map of a spherical array to the actual sound source is regarded as the combination of all of the imaginary sound sources. Sound source localization can be realized by calculating the contribution of each imaginary sound source to the sound field. Also in this work, the non-convex constrained optimization problem is established using p-norm. Combined with the norm method, the sparse solution of the imaginary sources is obtained through iterative weighted techniques, and the resolution of sound source localization is improved significantly. The performance of this method is investigated in comparison to conventional spherical beamforming. The numerical results show that the proposed method can achieve higher resolution for the localization of sound sources without being limited by the frequency and array aperture, and has a stronger ability to suppress fluctuations in background noise.

Highlights

The focused beamforming array signal processing technique is widely applied to radiation noise detection and the positioning of aircrafts, automobiles and ships due to its good tolerance and simplicity [1]
The spherical array can be widely used for sound field analysis and sound source localization in three-dimensional space due to its symmetry and rotation
In spherical array beamforming, which was first presented by Meyer and Abhayapala [2,3,4], the sound field is decomposed into spherical harmonic functions, including the scattering sound field

Summary

Introduction

The focused beamforming array signal processing technique is widely applied to radiation noise detection and the positioning of aircrafts, automobiles and ships due to its good tolerance and simplicity [1]. The spherical array can be widely used for sound field analysis and sound source localization in three-dimensional space due to its symmetry and rotation. Li et al studied the design and optimization of array distributions based on the genetic algorithm [5,6,7], which results in the reduction of the side lobe in the focusing spectrum. A high-resolution and high-precision spherical reverse beamforming for sound source localization based on the inverse algorithm, which utilizes the theory of conventional spherical beamforming and the structure and sound properties of the rigid spherical array, is proposed. The positioning performance is not affected by the frequency and the array aperture, and can be applied to detect low-frequency noise sources

Regular Spherical Array Beamforming

Spherical

Numerical Examples and Results

The Stability of SRFB