一种浅海声矢量场干涉结构提取方法

An extraction method for the interference striation of acoustic vector fields in shallow water

针对浅海Pekeris环境下声矢量场的干涉特征,基于简正波理论分析了在频率-距离域上声强谱、质点振速自谱、复声强谱和波阻抗谱干涉结构的形成机理,探讨了对干涉结构的波导不变量表征,并进行了宽带辐射声场干涉结构的海上测量试验。仿真研究和海试数据分析均表明,在频率-距离域上,上述4类物理量都会呈现稳定的、可用波导不变量β表征的干涉结构,而复声强独有的纯干涉分量更能体现波导的干涉效应。最后引入多尺度线性滤波器对海试实测LOFAR图进行处理,处理结果表明该滤波器可有效地增强干涉特征,更利于检测和提取干涉图案中的条纹信息。

According to the interference of acoustic vector field in a Pekeris waveguide of shallow water environment,it analyzes the formation mechanism of sound intensity spectrum, particle vibration velocity spectrum, complex sound intensity spectrum and waveguide impedance spectrum interference structure based on the Normal Mode Theory, explores the waveguide invariant representations of interference structure in frequency-range domain, and conducts a sea-trial for interference structure with a broadband radiated source. Both the sim^llation research and the analysis of sea- trial data indicate that, in frequency-range domain, the above four kinds of physical quantities will exhibit a stable interference structure which can be represented with waveguide invariant/~, and the interference components of complex sound intensity will better reflect the interference characteristics of the waveguide. Finally, a multi-scale linear filter is introduced for image processing of LOFAR gram which measured in sea-trial, the processing results show that the proposed filter can effectively enhance the interference characteristics, and conductively detect and extract striations＇ information from interference structures.