球谐函数波束形成声源识别扩展方法

Extension Method of Spherical Harmonics Beamforming for Sound Source Identification

球阵列波束形成是一种有效的三维空间声源识别技术,已有的球谐函数波束形成方法虽然能够准确定位声源,但无法定量声源的声学贡献,且声源识别结果受聚焦距离影响显著。通常,各声源对阵列中心处的声压贡献是声源排序评价的有效依据,为准确计算该声压贡献,提出球谐函数波束形成扩展方法,探究聚焦距离对计算准确性的影响规律。针对已知声源的模拟仿真结果表明,该方法不仅能够准确定位声源,而且能够准确计算声源声压贡献,3 000 Hz以下频段的最大误差不超过0.5 d B,3 000~6 000 Hz频段的最大误差不超过1.5 d B,且准确性几乎不受聚焦距离的影响。扬声器声源试验证明了模拟计算的正确性及该方法在实际应用中的有效性。

Beamforming with a spherical array is an effective 3D sound source identification technology. The existed spherical harmonics beamforrning can locate sound sources accurately, but it fails to quantify the acoustical contributions of sound sources, and that its results are affected by the focus distance seriously. Usually, pressure contribution each sound source makes to the array centre is an effective basis in ranking sound sources. In order to calculate the pressure contribution, an extension method of spherical harmonics beamforming is proposed and the influence rule of focus distance on the accuracy of the method is explored. Simulations of the given sound sources show that the method can not only locate sound sources but also calculate sound pressure contributions accurately. Concretely, the maximum error is less than 0.5 dB up to 3 000 Hz and less than 1.5 dB in 3 000-6 000 Hz. In addition, the accuracy of the method is hardly affected by the focus distance. Finally, experiment with loudspeaker sound sources validates correctness of the simulations and effectiveness of the method in practical applications.