Study of Spherical Near-Field Acoustic Holography with Rigid Spherical Microphone Array

Abstract:

The aim of this paper is to investigate the impacts of various parameters of rigid spherical microphone array in detecting and locating interior sound source. Helmholtz Equations are adopted to express the sound field produced by the incident field and scattered field. The gradient of the pressure is zero at the surface for the sphere is rigid. Both the incident and scattered coefficient could be obtained by solving the Helmholtz Equation using the boundary condition. Then the interior sound field could be detected and located on with the methodology of spherical near-field acoustic holography (SNAH). This study is developed in two aspects，one is configuring the microphone in various distribution in the same sphere radius, and the other one is changing the radius of sphere array. Numerical simulations are carried out to determine the optimum microphone array configuration and structure parameters. One, two, and three sound sources are arranged respectively in different displacement to the sphere center and in different angle direction to simulate the real situation. During the experiments, Omni-directional speakers and beeps are adopted as sound sources. The result shows that the method to detect and locate sound source in interior sound field is valid.

• Periodical: Key Engineering Materials (Volume 546)
• Pages: 156-163
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.546.156
• Online since: March 2013
• Authors: Xin Guo Qiu, Ming Zong Li, Huan Cai Lu, Wei Jiang
• Keywords: Incident Pressure, Interior Sound Field, Rigid Spherical Microphone Array, Scattered Pressure, Spherical Near-Field Acoustic Holography (SNAH)

References

[1] Meyer, J. and G. Elko, A spherical microphone array for spatial sound recording[J]. 2002. 111(5): pp.2346-2346.

DOI: 10.1121/1.4809138

[2] Rafaely, B. Spatial Sampling and Beamforming for Spherical Microphone Arrays. in Hands-Free Speech Communication and Microphone Arrays, 2008. HSCMA 2008. (2008).

DOI: 10.1109/hscma.2008.4538673

[3] Rafaely, B. and M. Park. Super-resolution spherical microphone arrays[C]. in Electrical and Electronics Engineers in Israel, 2004. Proceedings. 2004 23rd IEEE Convention of. (2004).

DOI: 10.1109/eeei.2004.1361182

[4] Rafaely, B. Analysis and design of spherical microphone arrays[J]. Speech and Audio Processing, IEEE Transactions on, 2005. 13(1): pp.135-143.

DOI: 10.1109/tsa.2004.839244

[5] Rafaely, B. The Spherical-Shell Microphone Array. Audio, Speech, and Language Processing, IEEE Transactions on, 2008. 16(4): pp.740-747.

DOI: 10.1109/tasl.2008.920059

[6] Takashima, K. H. Nakagawa, and E. Williams, Vector intensity measurement with a rigid spherical microphone array in a vehicle cabin[J]. Acoustical Society of America Journal, 2008. 123: p.3312.

DOI: 10.1121/1.2933759

[7] Williams, E. et al. Volumetric acoustic vector intensity imager. The Journal of the Acoustical Society of America, 2006. 120: p.1887.

[8] Finn Jacobsen, G.M. Efrén Fernandez Grande and Jørgen Hald, Near Field Acoustic Holography with Microphones Mounted on a Rigid Sphere[C]. 37th International congress and exposition on noise control engineering (2008).

[9] Jacobsen, F. et al. Spherical near field acoustic holography with microphones on a rigid sphere[J]. Acoustical Society of America. Journal, 2008. 123(5): pp.3385-3385.

DOI: 10.1121/1.2934035

[10] Williams, E.G. Fourier acoustics: sound radiation and nearfield acoustical holography[M]. 1999: Academic Pr.

[11] Mhaskar, H.N. Weighted quadrature formulas and approximation by zonal function networks on the sphere. Journal of Complexity, 2006. 22(3): pp.348-370.

DOI: 10.1016/j.jco.2005.10.003

[12] Hardin, R. and N. Sloane, McLaren's improved snub cube and other new spherical designs in three dimensions. Discrete & Computational Geometry, 1996. 15(4): pp.429-441.

DOI: 10.1007/bf02711518