【作者】 李晶；

【导师】 车英；

【作者基本信息】 长春理工大学 ， 仪器科学与技术， 2021， 博士

【摘要】 海洋石油污染对生物多样性及生态环境具有严重危害,目前对海洋石油污染进行监测主要采用被动探测技术,包括紫外成像探测技术与红外成像探测技术。但被动探测技术仅限于白天光照条件较好的情况下进行测量。因此,研究基于高光谱激光雷达的主动探测技术变得尤为重要,该技术能够实现溢油区域的全天候观测,实时反应油面动态信息。常规激光雷达技术仅限于单一波段应用,无法精准获取海洋油面的光谱信息。本文围绕海洋石油污染监测技术,在激光雷达原理的基础上开展高光谱激光雷达监测技术的研究。高光谱激光雷达是一种能够主动获取光谱和空间信息的仪器,可以减轻环境光照对光谱信息采集的影响。本文阐述了国内外高光谱遥感技术的发展及高光谱激光雷达技术的研究现状,以及海面溢油检测技术的相关研究,进一步明确了高光谱激光雷达应用于海面溢油监测的技术需求,在综合分析了几方面因素的基础上提出了满足实际工作需求的技术指标。根据海洋溢油污染监测技术指标的具体要求,对新型全时多谱段激光雷达设计、制造、调校及定标等关键技术开展了深入研究。具体研究内容如下:(1)针对新型光谱监测技术指标要求和高光谱激光雷达特性,利用Code-V设计软件对前置望远系统进行了光学设计和仿真分析。同时,对与之相匹配的机械结构进行了设计,并制造了一套满足技术指标要求,且性能优良的光学系统。采用折反射系统结构形式,极大地简化了光学系统结构,为满足对目标的跟踪与精细结构测量,在共光路的基础上,加入可见光接收系统,使高光谱激光雷达在进行光谱测量的同时还具备目标定位与成像能力。(2)提出并构建了较完善的可见-近红外波段的光谱性能测试方法,对高光谱激光雷达原理样机的光谱范围、光谱响应、动态范围等反映仪器光谱性能的指标进行了较全面的评定,完成了高光谱激光雷达的定量化研究。(3)利用输出高稳定、能量可调谐的积分球,配备相应设备,对高光谱激光雷达原理样机的光谱辐亮度响应度和响应均匀性进行了综合评价,针对具体激光雷达原理样机给出了相应的修正公式。(4)分析并推导出了该高光谱激光雷达信噪比的计算公式,试验样机前置光学结构的光谱传输特性,结合实际实验结果,对该高光谱激光雷达样机在实际海面溢油监测工作中的信噪比进行了综合估计。(5)利用高光谱激光雷达样机对实验室模拟的水面溢油进行了实验探测,采用该样机对不同厚度水面原油溢油分别在日间和夜间进行了光谱辐照度测量和可见光相机成像,并通过改变水面温度实际测量了不同温度下和不同油膜厚度对反射光谱的特性变化。实验结果表明本文中所研制的高光谱激光雷达在海面原油溢油观测中,尤其在夜间观测中,能够准确的对受溢油覆盖的水面和清澈水面进行辨别,所采用的监测方法可适用于我国全海域,并且可根据所获取的光谱特性对污染程度做出较为准确的判断。本文从海洋石油溢油污染监测入手,研制出一台能够同时获取目标光谱信息和二维图像的高光谱激光雷达原理样机,该高光谱激光雷达覆盖400nm～1100nm波段范围,根据整机系统结构特点,通过仪器整体设计和评价工作,以及在海面溢油中的应用,对高光谱激光雷达在地物目标识别探测能力进行了评价和分析,对集成方法进行了研究,调试完成后的原理样机各项指标均满足应用需求,为我国海洋溢油提供一种新的监测手段,对未来海洋环境保护、海洋资源利用开发具有重要意义。更多还原

【Abstract】 Marine oil pollution is a serious hazard to biodiversity and the ecological environment and is currently monitored mainly by passive detection techniques,including ultraviolet imaging detection and infrared imaging detection technology.However,the passive detection technology is limited to the measurement during daytime with good lighting conditions.Therefore,it is particularly important to study the active detection technology based on hyperspectral lidar,which can achieve all-weather observation of the oil spill area and realtime response to the dynamic information of the oil surface.Conventional lidar technology is limited to single-band applications and cannot accurately acquire spectral information of the maritime oil spills.This dissertation focuses on monitoring technology of marine oil pollution and carries out research on hyperspectral lidar monitoring technology based on the lidar principle.Hyperspectral lidar is an instrument capable of actively acquiring spectral and spatial information,which can mitigate the influence of ambient light on spectral information acquisition.This dissertation describes the development of domestic and international hyperspectral remote sensing technology and the current research status of hyperspectral lidar technology,as well as the relevant research on maritime oil-spills detection technology,further clarifies the technical requirements of hyperspectral lidar applied to maritime oil-spills monitoring,and proposes technical indicators to meet the actual working requirements based on a comprehensive analysis of several factors.According to the specific requirements of the technical indicators for marine oil spill pollution monitoring,the key technologies for the design,manufacture,tuning and calibration of the new full-time multi-spectral lidar are studied in depth.The specific research content is as follows.(1)The optical design and simulation analysis of the front telescope system were carried out by using Code-V design software for the requirements of the new spectral monitoring technology index and the characteristics of the hyperspectral lidar.At the same time,the matching mechanical structure was designed and an optical system was manufactured to meet the requirements of the technical specifications and with excellent performance.The structure of the optical system is greatly simplified by the use of a folded reflection system.To satisfy the tracking and fine structure measurement of the target,a visible light receiving system is added based on the common optical path,so that the hyperspectral lidar can locate and image the target at the same time as the spectral measurement.(2)A comprehensive spectral performance test method for the visible and near-infrared wavelengths was proposed and constructed,and a more comprehensive evaluation of the spectral range,spectral response,dynamic range and other indicators reflecting the spectral performance of the hyperspectral lidar principle prototype was carried out to complete the quantitative study of hyperspectral lidar.(3)A comprehensive evaluation of the spectral irradiance responsiveness and response uniformity of the hyperspectral lidar principle prototype was carried out using an integrator sphere with highly stable output and tunable energy,equipped with the corresponding equipment,and the corresponding correction formulae were given for the specific lidar principle prototype.(4)The formula for calculating the signal-to-noise ratio of this hyperspectral lidar is analysed and derived.Based on the spectral transmission characteristics of the front optical structure of the experimental prototype with known maritime oil-spills remote sensing detection angle and detection distance,and combined with the actual experimental results,the signal-to-noise ratio of this hyperspectral lidar prototype is comprehensively estimated in the actual oil spill monitoring work on the sea surface.(5)The hyperspectral lidar prototype was used to experimentally detect the oil spill in a laboratory simulation.The spectral irradiance measurements and visible camera imaging were carried out at daytime and nighttime for different thicknesses of crude oil spill on the water surface,and the variation of the reflectance spectra at different temperatures and different oil film thicknesses were measured by varying the water surface temperature.The experimental results show that the hyperspectral lidar developed in this dissertation can accurately distinguish between oil-covered and clear water surfaces in the observation of oil spills at sea,especially at night,and that the monitoring method adopted can be applied to the whole sea area of China and can make a more accurate judgement on the pollution level based on the acquired spectral characteristics.In this dissertation,we develop a hyperspectral lidar prototype that can simultaneously acquire target spectral information and two-dimensional images,which covers the wavelength range of 400nm～1100nm and evaluate the overall design and evaluation of the instrument according to the structural characteristics of the whole system,as well as the application in the maritime oil spill.The principle prototype after commissioning meets all the application requirements,providing a new means of monitoring the marine oil spill in China,which is of great significance to the future marine environmental protection and marine resources utilization and development.更多还原