Decomposition of the time reversal operator: Detection and selective focusing on two scatterers
Decomposition of the time reversal operator: Detection and selective focusing on two scatterers
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DOI：
10.1121/1.415393
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发表时间：
1996-04-01
影响因子：
2.4
通讯作者：
Fink, M
中科院分区：
文献类型：
--
作者：
Prada, C;Manneville, S;Fink, M
时间反演算子分解（DORT）方法是一种使用发射-接收换能器阵列的选择性检测和聚焦技术。它依赖于Prada艾德等人[C. Prada，J. L.托马斯和M. Fink，J. Acoust.秒Am. 97，62-71（1995）]。时间反演算子被定义为K*（ω）K（ω），其中ω是频率，* 表示复共轭，并且K（ω）是声穿透时不变散射介质的L个换能器的阵列的传递矩阵。结果表明，这种时间反演算子可以对角化，并为理想地解决不同的反射率的散射体，其非零特征值的特征向量的每一个提供了相位法应用到换能器，以集中在一个散射体。DORT方法包括确定这些特征向量并将其用于选择性聚焦。本文提出了一个完整的分析，这种方法的情况下，两个散射体。给出了本征向量的数学表达式，并描述了几个实验结果。特别是，该方法的有效性，通过非均匀介质选择性地聚焦。(C)1996年美国声学学会。
The decomposition of the time reversal operator (DORT) method is a selective detection and focusing technique using an array of transmit-receive transducers. It relies on the theory of iterative time reversal mirrors which was presented by Prada ed al. [C. Prada, J. L. Thomas, and M. Fink, J. Acoust. Sec. Am. 97, 62-71 (1995)]. The time reversal operator was defined as K*(omega)K(omega), where omega is the frequency, * means complex conjugate, and K(omega) is the transfer matrix of the array of L transducers insonifying a time invariant scattering medium. It was shown that this time reversal operator can be diagonalized and that for ideally resolved scatterers of different reflectivities, each of its eigenvectors of nonzero eigenvalue provides the phase law to be applied to the transducers in order to focus on one of the scatterers. The DORT method consists in determining these eigenvectors and using them for the selective focusing. This paper presents a complete analysis of this method in the case of two scatterers. The mathematical expressions of the eigenvectors are given and several experimental results are described. In particular, the effectiveness of the method to focus selectively through an inhomogeneous medium is established. (C) 1996 Acoustical Society of America.