基于空间重构相干声源的麦克风阵列性能评价技术研究

Performance Evaluation Technology for Microphone Array Based on Spatial Coherent Sound Source Reconstruction

基于波束形成算法的麦克风阵列系统被广泛应用于噪声源定位中,空间分辨率、动态范围是阵列进行多声源定位中的关键性能参数.工程中常用的阵列性能评估方法为小尺寸声源测试法,受声源尺寸及指向性的影响,其在使用不同声源对同一阵列进行测试时,测试结果往往有较大误差,且该测试方法对环境要求较高.基于此,本文提出了一种基于多通道标准耦合腔声源的空间声源重构方法,可重构出任意位置、频率及强度的空间点声源,通过标准耦合腔输出至对应坐标的麦克风传感器,重构两个相干点声源可代替实际空间小尺度声源对麦克风阵列性能参数进行测量分析.本文选取工程中常用的30通道螺旋形麦克风阵列,分别进行数值模拟、标准耦合腔实验及实际小尺寸声源对比实验.在2~4 kHz频段内,多通道耦合腔标准相干声源对阵列的测试结果与数值模拟结果高度一致,表明该方法的有效性.实际小尺寸声源的对比实验结果表明:耦合腔标准声源重构法受测试环境影响程度更低,分析麦克风阵列性能时测量误差小、精度高.

The microphone array system based on the beamforming algorithm is widely applied in noise source location,and its spatial resolution and dynamic range are key performance parameters when it is used to locate multiple sound sources.As a commonly used array performance evaluation method in engineering,the small-scale sound source test method is affected by the size and directivity of the sound source.Therefore,when different sound sources are used to test the same array,the test results usually have large errors,and the test method has high requirements on the environment.On this basis,a spatial sound source reconstruction method based on multi-channel standard coupled cavity sound source is proposed in this paper,which can reconstruct a spatial point sound source of any position,frequency and intensity.This point sound source is output by the standard coupled cavity to the microphone sensor of the corresponding coordinates,and the reconstruction of two coherent point sound sources can replace the actual spatial small-scale sound source to measure and analyze the performance parameters of the microphone array.A 30-channel spiral microphone array commonly used in engineering was selected for conducting numerical simulations,a standard coupled cavity experiment and a contrast experiment with an actual small-scale sound source.In the 2—4 kHz frequency band,the test results of multi-channel coupled cavity standard coherent sound sources on the array were highly consistent with the numerical simulation results,indicating the effectiveness of the proposed method.The results of contrast experiment with the actual small-scale sound source show that the reconstruction method of coupled cavity standard sound source was less affected by the test environment.When this method was used to analyze the perform-ance of microphone array,the measurement error was small and the accuracy was high.