Acoustic holography with a concentric rigid and open spherical microphone array

2009 ◽  
Author(s):  
Abhaya Parthy ◽  
Craig Jin ◽  
Andre van Schaik
Keyword(s):  
Microphone Array ◽  
Acoustic Holography

Nearfield Acoustic Holography Using Energy-Based Measurements

2005 ◽  
Author(s):  
Michael C. Harris ◽  
Jonathan D. Blotter ◽  
Scott D. Sommerfeldt ◽  
Hans-Elias de Bree
Keyword(s):  
Microphone Array ◽  
Analytical Models ◽  
Acquisition Time ◽  
Test Case ◽  
Reconstruction Method ◽  
Analysis Tool ◽  
Analytical Prediction ◽  
Acoustic Holography ◽  
Data Acquisition Time ◽  
Nearfield Acoustic Holography

Since its conception in 1980, nearfield acoustic holography (NAH) has become an accepted analysis tool with a number of commercial packages now available. One limitation of NAH is that the acoustic field is reconstructed through a spatial sampling. Therefore, this technique becomes less efficient at higher frequencies where microphone array spacing must be reduced. Analytical models have indicated that an NAH method relying on energy-based measurements will provide the same reconstruction resolution of current NAH methods with significantly fewer measurement locations. This would lead to a considerable savings in data acquisition time for scanning array systems and reduce the inefficiency at high frequencies. The energy-based reconstruction method will be introduced. Experimental results will be presented for a planar test case and the resulting reconstruction accuracy will be compared to the analytical prediction model.

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

2013 ◽  
Vol 546 ◽  
pp. 156-163
Author(s):  
Xin Guo Qiu ◽  
Ming Zong Li ◽  
Huan Cai Lu ◽  
Wei Jiang
Keyword(s):  
Sound Source ◽  
Microphone Array ◽  
Near Field ◽  
Sound Field ◽  
Acoustic Holography ◽  
Real Situation ◽  
Helmholtz Equations ◽  
Sound Sources ◽  
Array Configuration ◽  
Sphere Radius

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.

scholarly journals Optimization of Fixed Microphone Array in High Speed Train Noises Identification Based on Far-Field Acoustic Holography

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Rujia Wang ◽  
Shaoyi Bei
Keyword(s):  
Objective Function ◽  
Sound Source ◽  
Source Identification ◽  
High Speed ◽  
Microphone Array ◽  
Sound Field ◽  
Optimization Method ◽  
Far Field ◽  
Acoustic Holography ◽  
Sound Source Identification

Acoustical holography has been widely applied for noise sources location and sound field measurement. Performance of the microphones array directly determines the sound source recognition method. Therefore, research is very important to the performance of the microphone array, its array of applications, selection, and how to design instructive. In this paper, based on acoustic holography moving sound source identification theory, the optimization method is applied in design of the microphone array, we select the main side lobe ratio and the main lobe area as the optimization objective function and then put the optimization method use in the sound source identification based on holography, and finally we designed this paper to optimize microphone array and compare the original array of equally spaced array with optimization results; by analyzing the optimization results and objectives, we get that the array can be achieved which is optimized not only to reduce the microphone but also to change objective function results, while improving the far-field acoustic holography resolving effect. Validation experiments have showed that the optimization method is suitable for high speed trains sound source identification microphone array optimization.

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