基于激光距离选通的非视域成像特性分析

Analysis of Non-line-of-sight Imaging Characteristics Based on Laser Range-gated Imaging

激光距离选通成像系统借助具有一定镜面反射特性的中介反射面可以实现绕过拐角对隐蔽目标成像,即非视域成像。在对中介反射面模型化的基础上,分析并推导非视域成像系统探测器光敏面上的信号辐照度与干扰辐照度,进而给出非视域图像的对比度模型;结合典型非视域成像系统参量,分析中介面反射特性及其位置对非视域成像的影响。分析结果表明:对于大多数实用的中介反射面,只有采用激光距离选通成像模式才能实现非视域成像;当探测器和目标的位置确定时,中介反射面距离目标越近,非视域成像系统探测、识别目标的难度就越大;在实际使用过程中,采取适当的使用策略或方法可以最大限度发挥系统的性能。文中建立的模型及分析结果对于非视域成像的理论研究、系统设计和实际应用具有指导意义。

Laser range-gated imaging systems can obtain the images of targets hidden around a corner by using an intermediary reflective surface with certain specular reflection characteristics.This imaging mode is called non-line-of-sight imaging.The target signal irradiance and disturbance radiation on the photodetector of a non-line-of-sight imaging system are analyzed based on the modeling of an intermediary reflective surface,and an image contrast model of a non-line-of-sight imaging system is constructed.The effects of the reflective characteristics of an intermediary reflective surface and the distance between the intermediary reflective surface and the target or the detector on the image quality are analyzed in terms of the parameters of a typical non-line-of-sight imaging system.The simulation results show that a laser range-gated imaging system is indispensable for non-line-of-sight imaging with commonly used intermediary reflective surfaces without significant specular reflection characteristics,and the distance of the intermediary reflective surface from the target has a significant effect on the non-line-of-sight imaging.When the locations of detector and target are fixed,the non-line-of-sight imaging system can hardly identify the target if the intermediary reflective surface is closer to the target.In practice,the performance of the nonline-of-sight imaging system can be maximized using an appropriate usage strategy.