红外与毫米波学报, 2018, 37 (4): 486, 网络出版: 2019-01-10
雷达成像和衍射层析的内在联系梳理
Relationship between radar imaging and diffraction tomography
雷达成像 衍射层析成像 电磁逆散射 等效原理 线性化近似 傅里叶成像 点扩展函数 radar imaging diffraction tomography inverse scattering equivalence principle linear approximation Fourier imaging point spread function
摘要
从方程描述、方程求解和方程解析解三个层面, 对雷达成像和衍射层析的内在联系进行了系统性梳理.首先, 介绍了描述成像问题的电磁散射方程, 发现描述雷达的方程是二维的面积分方程, 而描述衍射层析的方程是三维的体积分方程.指出成像对象不同是导致方程不同的根源, 并利用等效原理建立了两种成像间的联系.其次, 指出两种成像的相同点是, 对非线性的电磁散射方程的线性化近似求解.最后, 指出两种成像的回波信号(在空间谱域)和成像目标(在空间域)均构成一组傅里叶变换对.给出了两种成像的解析解的统一数学模型, 即成像结果可表示为观测点(散射系数或散射势)卷积点扩展函数(PSF)的形式.通过PSF对两者的成像性能进行了比较.
Abstract
Although the similarities between radar imaging and diffraction tomography have been recognized, the connection between them is often surprising to practitioners in these fields. The main goal of this paper is to consider together two imaging techniques and clarify the similarities and differences that exist between them. First, Two imaging techniques are derived from Stratton-Chu formula of the inverse scattering problem, which allows a clear understanding of the relationship between the imaging equations and the imaging targets. The targets reconstructed by radar imaging are the perfectly conducting bodies, the targets reconstructed by diffraction tomography are the dielectric bodies. Then, this derivation brings out the similarities of the solution to the unlinear imaging problem which are hidden by the linear approximation method, radar imaging from high frequency asymptotic approximation, diffraction tomography from weak scattering approximation. Finally, Two imaging techniques are discribed as Fourier imaging, which is used to identify the unknown image profile as the inverse Fourier Transform of some composite function constructed from the received data signals.
江舸, 经文, 成彬彬, 周剑雄, 张健. 雷达成像和衍射层析的内在联系梳理[J]. 红外与毫米波学报, 2018, 37(4): 486. JIANG Ge, JING Wen, CHENG Bin-Bin, ZHOU Jian-Xiong, ZHANG Jian. Relationship between radar imaging and diffraction tomography[J]. Journal of Infrared and Millimeter Waves, 2018, 37(4): 486.