利用声压幅值相关性识别声源特性研究

Characteristics Research of Identifying Sound Source by Using the Correlation of Sound Pressure Amplitude

基于相位信息识别声源的传统方法在测量声信号前需要进行严格的相位匹配,对测量设备要求较高。通过对延时求和波束形成算法作形式上的转化,说明其运算机制是利用声压信号相位进行相关诊断,进一步研究提出利用声信号幅值识别声源的方法。将传声器阵列测得的声压幅值组成声压幅值向量,与虚拟点声源声压幅值向量做内积,搜索内积模的最大值,根据柯西-施瓦兹不等式定理确定声源位置。建立相应的识别步骤,对球面波声源进行仿真识别,并比较本方法与波束形成方法的识别特性的差异,且进行相应的实验验证。结果表明,本方法能有效识别出简谐波声源,且拥有良好的抗噪能力,可消除波束形成法识别高频声源时出现的“鬼影”现象;当传声器阵列存在误差时,比波束形成法有更准确的识别结果。

The traditional method of using phase information to identify the sound source requires strict phase matching before measuring the sound signal, which has high requirements on the measurement equipment. In this paper,through the formal transformation of the delay-sum beamforming, it is shown that operation mechanism of the traditional method is a correlation diagnosis based on the phase of sound pressure signal. Then, a method for sound source localization using the amplitude of the sound signal is proposed. In this method, the sound pressure amplitude measured by the microphone array is rearranged to form a sound pressure amplitude vector, which is used to perform the inner product operation with the sound pressure amplitude vector of the virtual sound source. When the inner product modulus value reaches the maximum value, the sound source location is determined according to the Cauchy-Schwartz inequality theorem.Identification steps are established to identify the sound source of a simulated spherical wave. In addition, the identification characteristics of the proposed method and the beamforming method are compared and the corresponding test verification is carried out. The results show that the method can effectively identify the harmonic sound source and has a good anti-noise ability. In addition, it can eliminate the "ghost image" phenomenon which appears in the identification of high-frequency sound sources using the beamforming method, and has a more accurate recognition result than the beamforming method when the microphone array error exists.