基于曲率和的主动声呐干涉条纹特征表征方法

干涉条纹特征是主动声呐目标识别所依据的重要特征之一。在浅水域环境中，声波能量传播特性较为复杂，信号会经过发射源到目标以及目标到接收器这2条不同的路径，目标的散射特性在声波的入射模式和散射模式之间相互作用，使得主动声呐干涉条纹呈现弯曲的结构。为对干涉条纹特征进行表征，提出一种基于曲率和的声呐特征提取方法。根据浅海声场主动声呐频率-距离干涉条纹图得到一段区间内的干涉条纹曲线散点曲率值，利用曲率求和的方法刻画条纹的弯曲程度，进而表征这一区间内的条纹特征。在理想波导环境下计算刚性球体目标在不同频率段下的曲率特征，通过统计平均值的方式得到平均曲率和为0.6左右，从特征表征结果可以看出，曲率和可通过统计离散点曲率强度描述干涉条纹特征，且在同一环境条件下，发射频率越大时曲率和强度越小。根据实测数据进行计算得到曲率和为0.512，实验与理论结果较为吻合，表明通过该方法可以获取主动声呐干涉条纹特征，进而实现目标识别和探测。

Method for Characterizing Active Sonar Interference Fringes Based on the Sum of Curvature

Interference fringes are essential features for active sonar target recognition.In shallow-water environments, the energy propagation characteristics of acoustic waves are relatively complex, and signals follow two different paths:from the emitter to the target and from the target to the receiver.The scattering characteristics of the target interact between the incident and scattering modes of the acoustic waves, causing active sonar interference fringes to exhibit a curved structure.A sonar feature extraction method based on the sum of curvature is proposed to characterize the interference fringe features.According to the frequency-distance interference fringe pattern of an active sonar in a shallow-water sound field, the curvature value of scattered points on the interference fringe curve in a section is obtained.The curvature summation method is used to characterize the curvature of the fringe and the fringe characteristics in this section.In the ideal waveguide environment, the curvature characteristics of a rigid sphere target in different frequency bands are determined, and an average sum of the curvature of approximately 0.6 is obtained through statistical averaging.The characterization results reveal that the sum of curvature can describe the interference fringe characteristics based on the statistical discrete point curvature intensity.Under the same environmental conditions, the higher the emission frequency, the smaller the curvature and intensity.Based on the obtained data, the calculated sum of curvature is 0.512.Thus, the experimental results are consistent with the theoretical results.The results indicate that active sonar interference fringe features can be determined based on this method, and target recognition and detection can be realized.