自适应门控低信噪比非视域成像  

Adaptive gating for low signal-to-noise ratio non-line-of-sight imaging

作　　者：李敏[1,2,3,4] 罗一涵[1,2,3,4] †李泰霖 赵开元[1,2,3,4] 谭毅 谢宗良 LI Min;LUO Yihan;LI Tailin;ZHAO Kaiyuan;TAN Yi;XIE Zongliang(National Key Laboratory of Optical Field Manipulation Science and Technology,Chinese Academy of Sciences,Chengdu 610209,China;Key Laboratory of Optical Engineering,Chinese Academy of Sciences,Chengdu 610209,China;Institute of Optics and Electronics,Chinese Academy of Sciences,Chengdu 610209,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院光场调控科学技术全国重点实验室,成都610209 [2]中国科学院光束控制重点实验室,成都610209 [3]中国科学院光电技术研究所,成都610209 [4]中国科学院大学,北京100049

出　　处：《物理学报》2025年第4期103-117,共15页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62271468)资助的课题.

摘　　要：非视域成像技术是对视域外隐藏目标进行光学成像的新兴技术.由于历经多次漫反射,信号回波微弱,门控单光子雪崩二极管(single-photon avalanche diode,SPAD)在低信噪比环境中探测信号发挥了重要作用.然而,实际使用门控SPAD进行目标信号探测时,现有方法多需要借助先验信息进行门宽位置预设,无法完全避免非目标信号干扰和信号丢失,并且存在数据采集量大、耗时长等问题.针对上述问题,本文利用三角定位原理和少量特征点信息,提出一种自适应门控算法,该算法可自动识别回波信号并计算其宽度,无需额外先验信息或人工干预,降低数据采集量,提高处理效率等功能.同时,搭建了基于门控SPAD的共焦非视域成像系统,对提出的算法进行验证.此外,本文就门控SPAD对目标信号提升效果和目标成像质量进行了定量评估,并对比了主流的非视域图像重构算法成像质量.实验结果表明,自适应门控算法可以有效识别回波信号,实现门控参数的自动调节,并在减少数据采集量、提升处理效率的同时,提高目标成像质量.Non-line-of-sight(NLOS)imaging is an emerging optical imaging technique used for detecting hidden targets outside the line of sight.Due to multiple diffuse reflections,the signal echoes are weak,and gated singlephoton avalanche diode(SPAD)plays a pivotal role in signal detection under low signal-to-noise ratio(SNR)conditions.However,when gated SPAD is used for detecting a target signal,existing methods often depend on prior information to preset the gate width,which cannot fully mitigate non-target signal interference or signal loss.Additionally,these methods encountered some problems such as large data acquisition volumes and lengthy processing times.To address these challenges,an adaptive gating algorithm is proposed in this work based on the principle of maximizing the distance from the vertex of a triangle to its base.The algorithm possesses advantages of the linear variation in scan point positions and the echo information from specific feature points.It can automatically identify echo signals and compute their widths without additional prior information or manual intervention.This method reduces the amount of data collected,improves processing efficiency,and has other benefits.Moreover,a confocal NLOS imaging system based on gated SPAD is developed to validate the proposed algorithm.The work further quantitatively evaluates the enhancement of target signal detection and image quality achieved by gated SPAD,and compares its imaging performance with leading NLOS image reconstruction algorithms.Experimental results demonstrate that the adaptive gating algorithm can effectively identify echo signals,facilitate automatic adjustment of gating parameters,and significantly improve target imaging quality while reducing data acquisition volume and enhancing processing efficiency.

关 键 词：非视域成像 自适应门控 信噪比 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术] O439[自动化与计算机技术—计算机科学与技术]