旋转粗糙目标激光散射的高阶矩及动态散斑的微运动特征提取

The micro-motion characteristic of an object reflects the electromagnetic scattering property and geometry as well as motion of the object. The micro-motion signature extraction has a wide application prospect in many areas, such as, remote sensing, the ballistic missile defense, air defense operation and monitoring, and medicine. As the carrier of the scattering information of the object, laser speckle becomes the important basis to detection and recognition, analysis and test of the micro-motion characteristic of the object. Meanwhile, with the advantage of simple structure, no smooth surface, non-contact, lossless and real-time, the laser speckle measurement technique is gradually to be one of the research topics. Based on the electromagnetic scattering theory of rough target and the physical optic approximation, with the combination of the Gaussian-moment theorem and the Gram-Charlier series, the high-order moment of the laser scattering from rotating rough objects is researched, then the time-space correlation function of the dynamic speckle is obtained, the temporal and the spatial correlation functions are analyzed, respectively. Also, the temporal and the spatial characteristic parameters are extracted; the influence of the surface parameter and shape and size and rotating attitude and angle velocity of the scattering object on the scattering high-moment function and the speckle property is discussed. With measurement experimentally and data processing, combining the theoretical model with the experiment result, the micro-motion characteristic parameters of the rotating rough object are extracted by a suitable optimization method.

目标的微动特征反映了目标的电磁散射特性、几何结构和运动特征。目标微动特征的提取对遥感、弹道导弹防御、防空作战和监视以及医学等领域具有广泛的应用前景。激光散斑作为携带散射体信息的载体，是进行目标探测、识别、特征分析以及微运动检测的重要依据。散斑测量技术结构简单、不需要光滑表面、非接触、无损性和实时性等优点在光学测量中逐渐成为研究的热点。本项目从粗糙体的电磁散射理论出发，采用物理光学近似，结合高斯矩定理及Gram-Charlier级数展开方法研究了旋转粗糙物体激光散射的高阶矩；得到动态散斑的时间-空间互相关函数，分析动态散斑的时间和空间相关函数，提取动态散斑的时间、空间特征参数；讨论目标表面参数、形状和尺寸、旋转姿态角和角速度等对粗糙物体散射高阶矩和散斑特性的影响；通过旋转粗糙回转目标动态散斑的实验测量和数据处理，理论模型与实验结果相结合，选取优化方法完成对旋转粗糙目标微运动特征参数的提取。

目标的微动特征反映了目标的电磁散射特性、几何结构和运动特征。目标微动特征的提取对遥感、弹道导弹防御、防空作战和监视以及医学等领域具有广泛的应用前景。本项目通过研究粗糙目标散斑特性展开对目标微运动特征的分析研究。.从粗糙面电磁散射理论出发，采用物理光学近似，研究了粗糙凸回转目标的光散射特性及双频互相关函数，并且基于双向反射分布函数计算了粗糙目标散射截面以及锥体目标一维距离像；结合高斯矩定理推导了粗糙面散射四阶统计特性，并在此基础上研究了旋转粗糙物体激光散斑统计特性，分别得到散斑的空间相关函数和时间相关函数，提取空间相干长度得到不同空间粗糙面散斑和不同形状粗糙简单目标散斑尺寸；数值计算粗糙物体动态散斑时间相关特性，提取动态散斑时间相干长度，分析时间相干长度与目标的尺寸、旋转速度和姿态的关系；制备粗糙物体样品，采用表面轮廓仪测量表面粗糙度，搭建实验平台实时采集旋转粗糙目标动态散斑时序图，将动态散斑时间相干长度理论模拟值与实验数据对比，提取目标的旋转角速度及姿态角等微运动特征，为目标散射特性探测、特征识别和提取提供依据。