Focusing Waves Through a Randomly Scattering Medium in the White-Noise Paraxial Regime
Focusing Waves Through a Randomly Scattering Medium in the White-Noise Paraxial Regime
复制标题
在白噪声近轴状态下通过随机散射介质聚焦波
DOI：
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发表时间：
2016
影响因子：
1.9
通讯作者：
K. Sølna
中科院分区：
文献类型：
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作者：
J. Garnier;K. Sølna
当波在复杂或非均匀介质中传播时，波场会受到非均匀性的破坏。这种损坏限制了成像或通信方案的性能。然后，人们可能会问这样一个问题：是否存在一种对信号进行编码的最佳方式，以便抵消介质的破坏？在理想的情况下，答案是通过时间反演给出的：对于给定的目标或聚焦点，在第一步中，让目标发射信号，然后记录发送到源天线的信号，在第二步中，将其时间反演并将其用作源天线处的源轨迹。如果源孔径足够大，则该源将在目标位置处产生尖锐聚焦的波。在这里，我们解决这个计划在更实际的情况下，有限的孔径，时间谐波信号，和有限大小的元素在源阵列。中心问题是聚焦分辨率和目标的信噪比，它们对物理参数的依赖性，以及在目标点附近选择性聚焦并因此传输图像的能力。尖锐的结果为这些问题。
When waves propagate through a complex or heterogeneous medium the wave field is corrupted by the heterogeneities. Such corruption limits the performance of imaging or communication schemes. One may then ask the question: is there an optimal way of encoding a signal so as to counteract the corruption by the medium? In the ideal situation the answer is given by time reversal: for a given target or focusing point, in a first step let the target emit a signal and then record the signal transmitted to the source antenna, time reverse this and use it as the source trace at the source antenna in a second step. This source will give a sharply focused wave at the target location if the source aperture is large enough. Here we address this scheme in the more practical situation with a limited aperture, time-harmonic signal, and finite-sized elements in the source array. Central questions are then the focusing resolution and signal-to-noise ratio at the target, their dependence on the physical parameters, and the capacity to focus selectively in the neighborhood of the target point and therefore to transmit images. Sharp results are presented for these questions.