Sweep distortion removal from terahertz images via blind demodulation
Sweep distortion removal from terahertz images via blind demodulation
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DOI：
10.1364/optica.3.000754
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发表时间：
2016-07-20
期刊：
影响因子：
10.4
通讯作者：
Raskar, Ramesh
中科院分区：
文献类型：
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作者：
Aghasi, Alireza;Heshmat, Barmak;Raskar, Ramesh
通过散射层的检测和成像是光学领域几十年来的老问题。与X射线和超声成像技术不同，时域光谱法可以提供详细的化学和结构信息的子表面沿着其深度。虽然时域光谱中的高分辨率飞行时间测量提供了3D信息，但不幸的是，它也会对系统的未对准和层本身的失真产生不必要的敏感性。这种对对准和样品表面的高灵敏度是时域和干涉成像中的众所周知的问题，并且当对准误差与脉冲波长相当时是主要关注的问题。在这里，我们提出并实现了一个基于低秩矩阵恢复和交替最小化的算法框架，以消除时域图像中不必要的失真。该方法允许恢复的原始样本纹理，尽管存在的时间-空间失真。我们解决一个盲解调的问题，基于几个观察的样本纹理调制不希望的扫描失真，两类信号分离的主要功能的损害最小。在太赫兹时域系统的情况下，在合成和真实的数据中检查该方法的性能，并证明了成功的重建。所提出的一般方案可以实施，以推进太赫兹和其他时间分辨光谱成像模式中的检查和成像应用。(C)2016美国光学学会
Inspection and imaging through scattering layers is a decades-old problem in optics. Unlike x-ray and ultrasonic imaging techniques, time-domain spectroscopy methods can provide detailed chemical and structural information of subsurfaces along with their depth. Although high-resolution time-of-flight measurement in time-domain spectroscopy provides 3D information, unfortunately it also induces an unwanted sensitivity to misalignments of the system and distortion of the layers themselves. Such high sensitivity to alignment and sample surface is a well known problem in time-domain and interferometric imaging, and is a major concern when the alignment error is comparable to the pulse wavelength. Here, we propose and implement an algorithmic framework based on low-rank matrix recovery and alternating minimization to remove such unwanted distortions from time-domain images. The method allows for recovery of the original sample texture in spite of the presence of temporal-spatial distortions. We address a blind-demodulation problem where, based on several observations of the sample texture modulated by undesired sweep distortions, the two classes of signals are separated with minimal damage to the main features. The performance of the method is examined in both synthetic and real data in the case of a terahertz time-domain system, and the successful reconstructions are demonstrated. The proposed general scheme can be implemented to advance inspection and imaging applications in THz and other time-resolved spectral imaging modalities. (C) 2016 Optical Society of America