论文部分内容阅读
针对基于金属腔体的微波断层成像系统,提出了一种最优分层非均一背景的设计方法.该方法使用一种新的微波断层成像积分算子评价方法和模拟退火法等最优化方法.首先,介绍了一种基于有限元法的微波断层成像积分算子计算方法.然后,提出一种新的微波断层成像积分算子度量,该度量可以综合评价整个积分算子奇异值谱,并通过一组仿真研究证明该度量与反演结果的误差具有相关性;该度量用一个数值综合评价一个积分算子,可以方便地应用于最优化算法中;利用模拟退火法选择圆形金属腔体中分层非均一背景的每一层介质的相对介电常数,从而获得一个最优分层非均一背景.最后,对尺寸小于半波长的圆柱目标和“凹”字形复杂目标进行仿真研究,仿真结果证明该最优分层非均一背景可以提高微波断层成像算法的收敛速度,提高反演结果的准确性.
Aiming at the metal cavity-based microwave tomography system, a design method of optimally stratified non-uniform background is proposed, which uses a new optimization method such as integrated operator evaluation of microwave tomography and simulated annealing. First of all, a method of calculating integral operator of microwave tomography based on finite element method is introduced, then a new integral operator metric of microwave tomography is proposed, which can comprehensively evaluate the singular value spectrum of integral operator and pass A set of simulation studies have shown that the measurement is inversely related to the error of the inversion results. The metric can be conveniently applied to the optimization algorithm by using a numerical evaluation of an integral operator. The simulated annealing method can be used to select the circular metal cavity The relative permittivity of each layer of the medium with different layers is obtained, and an optimal layered non-uniform background can be obtained.Finally, the simulation of cylindrical targets smaller than half wavelength and complex targets of " Simulation results show that the optimal hierarchical non-uniform background can improve the convergence rate of the microwave tomography algorithm and improve the accuracy of the inversion results.