SAR分布目标多视图像分辨特性研究

Study on Distributed Targets Resolution of Multilook SAR Image

该文提出了结合目标特性与图像多视数对SAR分辨特性进行分析和评定的方法。基于对SAR目标可分辨概率的研究,以及对SAR复散射回波信号特性的分析,得到了目标之间关于信号幅度比、相位差和多视数的联合概率密度函数,建立了SAR分布目标可分辨特性与目标统计特性以及图像多视数之间的数学关系模型。结合目标可区分条件,探讨分析了目标统计特性和多视处理对SAR系统分辨特性的影响。从该文的研究分析可以看出,由于分布目标信号具有的随机特性,在目标间距离小于传统的分辨率时也存在可分辨性,目标间距离大于系统分辨率时也存在不可分辨性。多视处理相当于增加了目标间的相关性,同样对SAR的分辨特性有较大的影响。该文提出的分辨特性评价指标将SAR系统特性与目标特性相结合,更能真实反映SAR的分辨性能,对SAR系统参数设计和评定有重要意义。

A method is proposed to analyze and assess the SAR resolution, which considers the statistical characteristics of the distributed targets and the number of multi-look. The joint probability density function of two points on the amplitude radio, phase difference, correlation coefficient, and the number of multi-look is deduced from the SAR complex scattering echo signal. Based on the study of the SAR separable probability and the PDF, a mathematical model is built that reflects the mathematical relationship between the SAR resolution and the statistical properties of the targets and the number of multi-look. Considering the condition that the points can be separated, the influence that the statistical properties of SAR distributed targets and multi-look processing have on SAR resolution is discussed. From the numerical results, when the distance between targets is less than the traditional resolution, the targets also can be distinguished; and when the distance is larger than the traditional resolution, the targets may not be distinguished. The effect of multi-look processing is equivalent to increasing the relevance between the targets, and it also has great influence on SAR resolution. The separable probability can reflect the resolution performance correctly and is important for designing and evaluating the SAR system.