Sound source localization \u2013 state of the art and new inverse scheme

Stefan Gombots,Jonathan Nowak,Manfred Kaltenbacher

doi:10.1007/s00502-021-00881-6

Stefan Gombots, Jonathan Nowak + Show 1 more

Open Access

https://doi.org/10.1007/s00502-021-00881-6

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Abstract

Acoustic source localization techniques in combination with microphone array measurements have become an important tool for noise reduction tasks. A common technique for this purpose is acoustic beamforming, which can be used to determine the source locations and source distribution. Advantages are that common algorithms such as conventional beamforming, functional beamforming or deconvolution techniques (e.g., Clean-SC) are robust and fast. In most cases, however, a simple source model is applied and the Green’s function for free radiation is used as transfer function between source and microphone. Additionally, without any further signal processing, only stationary sound sources are covered. To overcome the limitation of stationary sound sources, two approaches of beamforming for rotating sound sources are presented, e.g., in an axial fan.Regarding the restrictions concerning source model and boundary conditions, an inverse method is proposed in which the wave equation in the frequency domain (Helmholtz equation) is solved with the corresponding boundary conditions using the finite element method. The inverse scheme is based on minimizing a Tikhonov functional matching measured microphone signals with simulated ones. This method identifies the amplitude and phase information of the acoustic sources so that the prevailing sound field can be with a high degree of accuracy.

Highlights

Sound emissions from technical applications and production machines are perceived as disturbing noise
4.1 Low-frequency sound source in a room To demonstrate the applicability of the inverse scheme in real-world scenarios, microphone array measurements were performed in a room where a generic sound source was located
A main restriction in current beamforming methods is given by the assumption of free radiation for the calculation of the transfer function between microphone and assumed source point

Summary

Introduction

Sound emissions from technical applications and production machines are perceived as disturbing noise. The latter method for compensating the rotation of a sound source uses modal decomposition of the acoustic pressure signals in the frequency domain and a modified Green’s function for the rotating monopole as steering vectors [18]. 4.1 Low-frequency sound source in a room To demonstrate the applicability of the inverse scheme in real-world scenarios, microphone array measurements were performed in a room where a generic sound source was located.

Results

Conclusion