剪切光束成像技术稀疏重构算法  

Spatial domain sparse reconstruction algorithm of sheared beam imaging

作　　者：陈明徕 刘辉[1,2,3] 张羽 罗秀娟[1,2,3] 马彩文[1,2,3] 岳泽霖[1,2] 赵晶 Chen Ming-Lai;Liu Hui;Zhang Yu;Luo Xiu-Juan;Ma Cai-Wen;Yue Ze-Lin;Zhao Jing(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;Key Laboratory of Space Precision Measurement Technology,Chinese Academy of Sciences,Xi’an 710119,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 [3]中国科学院空间精密测量技术重点实验室,西安710119

出　　处：《物理学报》2022年第19期128-136,共9页Acta Physica Sinica

基　　金：陕西省自然科学基础研究计划(批准号:2020JQ-438)资助的课题。

摘　　要：在对低轨道运动目标成像时,剪切光束成像接收系统所需的探测器阵元数目非常庞大,探测器接收阵列的研制难度大,成本高.本文提出剪切光束成像系统空域稀疏采样技术,同时发射五束激光照射目标携带更多的频谱信息,研究稀疏重构算法,在经稀疏采样的回波信号中提取目标的相位差和振幅信息,通过波前恢复重构目标图像.理论上,在不影响分辨率的前提下,探测器阵列阵元数目可稀疏为传统三光束方法的1/2,突破了探测器阵元间距与发射剪切量相等的限制.仿真结果表明,与传统三光束方法相比,所提稀疏重构算法在探测器阵元数目稀疏一倍的情况下,重构图像质量几乎相同.Sheared beam imaging(SBI) is considered a computational imaging technique that transmits three sheared coherent laser beamlets for illumination,and a sensor array to receive the intensity of the speckle pattern reflected from the target.The SBI can be used to image remote objects through a turbulent medium with no need of any adaptive optics.However,while imaging low-orbit moving targets,the number of detectors of sensor array required by the receiving system of SBI is very large,and the development of sensor array is difficult and costly.In this work,a spatial domain sparse sampling technique is proposed for the SBI system through transmitting five laser beamlets to illuminate the target carrying more of its spectral information,which can reduce the number of detectors of the sensor array.Firstly,the principle of the sparse imaging technique is deduced.Then,a sparse reconstruction algorithm is studied.The phase difference and amplitude information of the target in the echo signal after sparse sampling can be extracted accurately by searching for the accurate positions of the beat frequency components.The wavefront phases can be demodulated by the least-squares method,and wavefront amplitude can be obtained by the algebraic operation of speckle amplitude.The reconstructed wavefront is used to formulate the two-dimension image of the target.Theoretically,without affecting the resolution,the number of detectors of the sensor array can be reduced to half of the traditional three-beam method,which breaks through the limitation that the detector spacing of sensor array is equal to the shear length of beamlet.From the simulation results,when the number of detectors of the sensor array is reduced by 50%,the proposed sparse reconstruction algorithm has almost the same quality as the reconstructed image with the traditional three-beam method.

关 键 词：剪切光束成像 空域稀疏采样 稀疏重构算法 探测器阵列 

分 类 号：O439[机械工程—光学工程] TP391.41[理学—光学]