透过散射介质对直线运动目标的全光成像及追踪技术  

All-optical imaging and tracking technology for rectilinear motion targets through scattering media

作　　者：贾辉 罗秀娟[1] 张羽[1] 兰富洋 刘辉[1,2] 陈明徕 Jia Hui;Luo Xiu-Juan;Zhang Yu;Lan Fu-Yang;Liu Hui;Chen Ming-Lai(Xi＇an Institute of Optics and Precision Mechanics,Chinese Academy of Sciences,Xi＇an 710119,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院西安光学精密机械研究所,西安710119 [2]中国科学院大学,北京100049

出　　处：《物理学报》2018年第22期234-241,共8页Acta Physica Sinica

摘　　要：光散射是限制光传输以及降低和破坏光学成像性能的主要因素,透过复杂散射介质对运动目标的全光成像是光学领域极具挑战性的技术之一.本文提出一种利用散斑差值自相关透过散射介质对运动目标进行实时追踪的方法.采用赝热光照明,基于光学记忆效应理论,通过对运动目标采集的两帧散斑做差值,然后做自相关运算,计算目标移动的距离,实现对目标的实时追踪,并且利用相位恢复算法进行简单处理就可以重建隐藏目标.对该方法进行了实验验证,成功地对隐藏的运动目标实现了成像与追踪.这种透过散射介质对运动目标的全光成像及实时追踪技术,在生物医学等领域具有重要应用潜力.Light scattering is a main factor that restricts optical transmission and deteriorates optical imaging performance.All-optical imaging for moving targets through complex scattering media is one of the most challenging techniques. In this paper, a method for real-time tracking of moving targets through scattering medium is presented by utilizing optical memory-effect and autocorrelation of speckle difference. In the experiment on imaging through a scattering medium, an object is hidden at a distance u behind a highly scattering medium. The object is illuminated by a spatially incoherent pseudothermal light source. The light is diffused through the scattering medium. Camera placed at a distance u0 on the other side of the medium records the pattern of the scattered light. According to the theory of optical memory-effect,the process of scattering imaging is a convolution process of point spread function（PSF） and object. In the procedure of object moving, the scattered signals from two frames are captured. The background noise could be removed by subtracting the two captured image. Then, the autocorrelation operation calculates the speckle difference, and hidden targets can be effectively reconstructed with the phase retrieval algorithm. The experiment demonstrates the imaging of targets with different speeds. The results have shown that the faster the speed, the worse the imaging quality is. High-speed moving objects can be imaged by using a high frame rate camera to reduce the exposure time or by disambiguating the speckle pattern. In subsequent experiments, the distance of the target movement is calculated with the magnification of the system. The collected two frames of speckle must be within the same memory effect angle.Only in this way can the calculation accuracy of the motion distance be guaranteed. With the moving of the target,the cross-correlation information of the target appears at different positions of the speckle difference autocorrelation map. Finally, according to the cross-correlation of the ta

关 键 词：透过散射介质成像 散斑差值自相关 光学记忆效应 运动目标 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术] O436.2[自动化与计算机技术—计算机科学与技术]