Two-dimensional FDTD inverse-scattering scheme for determination of near-surface material properties
Two-dimensional FDTD inverse-scattering scheme for determination of near-surface material properties
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用于确定近表面材料特性的二维 FDTD 逆散射方案
DOI：
10.1109/aps.2003.1217511
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
A. Taflove
中科院分区：
文献类型：
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作者：
M. Popovic;A. Taflove
文献中发现的数值反散射研究是基于频域或时域方法。频域算法会产生大量的未知参数。相比之下。时域方法可以利用因果关系来限制反演的区域，潜在地减少未知的数量。与我们的工作最相关的方法是反散射方案的一维（1D）时域有限差分公式，用于遥感非均匀有损层状介质（Umashankar， K.R.等人，1994）。在假设正常入射的平面波脉冲和接收到的脉冲上存在零噪声的情况下，采用剥离层法同时恢复电导率和介电常数曲线。我们的工作将这种技术扩展到二维（2D）分层有损半空间的情况下，在其表面被无限长的单极子脉冲激发。该算法通过在表层（/spl epsiv//sub r/, /spl sigma/）参数空间中生成搜索轨迹，可以同时估计表层的介电常数/spl epsiv//sub r/和电导率/spl sigma/。在存在高斯噪声的情况下，对算法的鲁棒性进行了测试。我们通过测量女性乳房的介电参数和皮肤厚度来说明我们的新算法。监测乳房近表面特征可能有助于潜在组织病变的预诊断。
Numerical inverse-scattering studies found in the literature are based on either frequency- or time-domain approaches. Frequency-domain algorithms can result in a very large number of unknown parameters. In contrast. time-domain approaches can exploit causality to limit the region of inversion, potentially reducing the number of unknowns. The most relevant approach to our work is the one-dimensional (1D) FDTD formulation of an inverse-scattering scheme for remote sensing of inhomogeneous lossy layered media (Umashankar, K.R. et al., 1994). A layer-stripping procedure was used to recover the conductivity and permittivity profiles simultaneously, assuming a normally incident plane wave pulse and zero noise present on the received pulse. Our work extends that technique to the case of a two-dimensional (2D) layered lossy half-space impulsively excited at its surface by an infinitely long monopole. The new algorithm permits simultaneous estimation of the electrical permittivity, /spl epsiv//sub r/, and conductivity, /spl sigma/, of a surface layer by generating a search trajectory in the (/spl epsiv//sub r/, /spl sigma/) parameter space of the layer. The robustness of the algorithm is tested in the presence of Gaussian noise. We illustrate our new algorithm by the measurement of the dielectric parameters and skin thickness of the female human breast. Monitoring of near-surface breast properties may be useful for the prediagnosis of underlying tissue pathologies.