沙氏激光雷达探测水体衰减系数  

Development of Scheimpflug Lidar Technique for Measuring Attenuation Coefficient of Water Body

作　　者：刘子凡 车昊 宫振峰 刘琨 梅亮 Liu Zifan;Che Hao;Gong Zhenfeng;Liu Kun;Mei Liang(School of Optoelectronic Engineering and Instrumentation Science,Dalian University of China,Dalian 116024,Liaoning,China)

机构地区：[1]大连理工大学光电工程与仪器科学学院,辽宁大连116024

出　　处：《中国激光》2022年第12期312-320,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(62075025);大连市高层次人才创新支持计划(2020RQ018)。

摘　　要：根据沙氏成像原理,采用450 nm高功率二极管激光器作为光源,CMOS图像传感器作为探测器,研制了一种水体沙氏激光雷达,并利用该雷达系统实现了动态水体衰减系数测量。针对空气-玻璃-水体交界面的折射效应,对水体测量时的像素-距离关系进行修正。在实验室内,利用沙氏激光雷达系统对加入不同质量浓度脂肪乳(Intralipid)的水体进行探测研究,并利用斜率法及Klett法反演得到水体衰减系数。实验结果表明,沙氏激光雷达不仅可以捕捉水体动态变化过程,而且反演获得的水体衰减系数与加入的脂肪乳质量浓度具有良好的一致性,证明了沙氏激光雷达用于水体衰减系数定量探测的可行性,为下一步开放水域测量提供了参考。Objective Optical parameters such as the attenuation coefficient are important environmental indicators of water bodies,including ocean,lakes,and rivers.The accurate measurement of the optical parameters of water bodies is crucial for ocean color remote sensing,ocean carbon cycle research,and ocean primary productivity assessment.Recently,the lidar technology has been gradually employed in the measurements of the marine chlorophyll concentration,scattering layer,optical attenuation coefficient,etc.However,the currently available lidar technique is mainly based on the time-of-flight principle,putting high demands on the laser energy,laser pulse width,and signal sampling rate to achieve large-depth and high-spatial-resolution measurements.In this work,we have designed and developed a Scheimpflug lidar(SLidar)system based on the Scheimpflug imaging principle(Fig.1)for attenuation coefficient measurements in water bodies.The SLidar technique features a high range resolution,low cost,low maintenance,and wide wavelength selectivity,which can provide a novel approach for the quantitative detection of the water-body attenuation coefficient.Methods The water-body SLidar system(Fig.2)mainly includes three parts:transmitting,receiving,and control units.The transmitting unit comprises a 450 nm multimode laser diode and a collimating lens.The 15-mm collimated laser beam is transmitted into a water tank.The backscattered light is collected using a receiving lens and then detected using a 45°tilted CMOS camera with an interference filter for ambient light rejection.The distance between the transmitting and receiving units is~100 mm to satisfy the Scheimpflug principle.During measurements,the laser diode is on-off modulated and synchronized with the exposure of the CMOS camera,which alternately acquires the laser beam image and the background image.Thus,the dynamic subtraction of the background signal is achieved.In addition,the pixel-distance relation(Fig.3)in water-body measurements is evaluated by considering the refraction

关 键 词：遥感 沙氏激光雷达 沙氏成像原理 衰减系数 二极管激光器 水体探测 

分 类 号：O436[机械工程—光学工程]