推扫式可见光／近红外成像光谱仪的在轨光谱定标与偏振校正技术研究

发布时间：2018-04-20 01:39

本文选题：成像光谱仪 + 可见光/近红外　；参考：《中国科学院研究生院(上海技术物理研究所)》2016年博士论文

【摘要】：卫星海洋遥感技术被公认为是海洋环境调查、监测的重要手段,广泛用于水体初级生产力评估、渔业资源开发、海洋污染检测与防治等方面。随着空间遥感定量化应用进一步发展,对成像遥感仪器的辐射定标精度提出了更高的要求。“宽波段成像仪”主要用于海洋水色遥感,装载在我国某地球低轨道应用平台,计划于年内发射入轨。其中,可见光/近红外模块是整个载荷的主要子系统。本文基于该型号项目,以提高星载推扫式光栅色散型可见光/近红外成像光谱仪的在轨辐射测量精度为目标,从在轨光谱定标、偏振校正两个方面展开深入研究。本文主要内容包括:1)针对可见光/近红外成像光谱仪的指标要求,介绍了仪器的系统设计方案、光校装调方法以及星上定标装置,发射前开展了性能参数测试与辐射定标实验,给出可见光/近红外成像光谱仪的性能测试与定标结果。2)通过模型仿真评估了光谱漂移对可见光/近红外成像光谱仪辐射测量精度的影响,仿真结果表明,漂移对太阳夫琅和费、氧气和水汽特征峰附近通道的辐射测量影响最大。典型观测条件下,当带宽为10nm时,光谱中心波长漂移1nm引入的测量误差约为5%,漂移2.5nm时,测量误差10%。3)理论分析了全帧模式光谱响应函数与分通道模式光谱响应函数之间的关系,提出了通道合成技术,根据全帧光谱响应函数实现分通道光谱响应函数的合成,为缺省和可编程的分通道模式的在轨光谱定标打下基础。4)基于谱线匹配思想,提出利用太阳夫琅和费线与大气吸收谱线以及星上定标器镨钕玻璃吸收峰进行光谱定标的方法。分别使用外场太阳漫反射板以及星上定标器内部光源开展了在轨光谱定标模拟实验。采用相关系数与最小二乘联合优化算法对实验数据进行了处理,结果表明算法对光谱变化灵敏度高,中心波长定位的标准偏差优于0.176nm,较直观比对法的精度提高了一个数量级。5)基于Stoke矢量与Mueller矩阵推演了仪器偏振响应方程,分析了偏振影响辐射定标的原理。在此基础之上,提出了成像仪偏振校正算法,通过求取偏振响应系数对测量值进行校正;以可见光/近红外成像光谱仪的光谱通道CH10穿轨视场第797像元为例,利用Stokes矢量已知的部分偏振光对算法进行了验证,结果表明,该算法适用于成像光谱仪偏振响应校正。在入射光束为完全线偏光且偏振状态已知的情况下,根据不同通道视场像元的偏振响应幅度,该算法可将偏振引入的大气顶入瞳辐射测量不确定度降低1%-6%,残余偏振灵敏度0.4%,能够提高海洋遥感离水辐射的测量精度。6)搭建了仪器偏振响应特性测试系统,测量了可见光/近红外成像光谱仪项目工程样机的偏振响应幅度和相位角,它们是光谱通道和视场像元的函数。980nm波段偏振灵敏度平均值为4.69%,413nm波段平均值为1.88%,生成了14个光谱通道×1024个视场像元偏振响应参数查找表,为仪器在轨偏振校正提供了参考。
[Abstract]:Satellite remote sensing technology is recognized as an important means of marine environmental investigation and monitoring. It is widely used in water primary productivity assessment, fishery resources development, marine pollution detection and prevention and so on. With the further development of spatial remote sensing application, a higher requirement for radiometric calibration of imaging remote sensing instrument is put forward. The waveband imager is mainly used for ocean water color remote sensing, and is loaded in a low orbit application platform in our country. It is planned to launch into the orbit within the year. Among them, the visible light / near infrared module is the main subsystem of the whole load. This paper is based on this model to improve the orbit of the spaceborne Bragg grating dispersive visible light / near infrared imaging spectrometer. The accuracy of radiation measurement is the target, from two aspects of orbit spectral calibration and polarization correction. The main contents of this paper are as follows: 1) in view of the requirements of the visible light / near infrared imaging spectrometer, the system design scheme, the light correction method and the star calibration device are introduced. The performance parameters test and the radiance are carried out before the launch. The performance test and calibration result.2 of the visible light / near-infrared imaging spectrometer are given. The effect of the spectral drift on the measurement accuracy of the visible light / near infrared imaging spectrometer is evaluated by the model simulation. The simulation results show that the drift is affected by the radiation measurement of the sun Fraunhofer, the oxygen gas and the water vapor characteristic peaks. Under typical observation conditions, when the bandwidth is 10nm, the measurement error of the spectral center wavelength shift 1nm is about 5% and the drift 2.5nm, measurement error 10%.3). The relationship between the spectral response function of the whole frame mode and the spectral response function of the channel mode is theoretically analyzed, and the channel synthesis technology is proposed, which is based on the full frame spectral response function. The present split channel spectral response function is synthesized to lay a foundation.4 for the default and programmable on track spectral calibration. Based on the spectral line matching idea, a method of using the sun Fraunhofer line with the absorption spectrum of the atmosphere and the absorption peak of the praseodymium and neodymium glass in the star set is proposed. The external field solar diffuse reflection is used respectively. The experimental data are processed by the correlation coefficient and the least square optimization algorithm. The results show that the algorithm has high sensitivity to the spectral change and the standard deviation of the central wavelength location is better than that of 0.176nm, and the accuracy of the method is increased by one quantity compared with the visual comparison method. Level.5) based on the Stoke vector and Mueller matrix, the polarization response equation of the instrument is deduced and the principle of polarization influence radiation calibration is analyzed. On this basis, the polarization correction algorithm of the imager is proposed. The measurement value is corrected by obtaining the polarization response coefficient, and the spectral path of the visible light / near infrared imaging spectrometer is seventh. 97 pixel is used as an example to verify the algorithm by using partial polarized light known by the Stokes vector. The results show that the algorithm is suitable for the polarization response correction of the imaging spectrometer. In the case of a complete linear polarization and the known polarization state of the incident beam, the algorithm can introduce the polarization of the polarization in the different channel field of view. The uncertainty of the air top pupil radiation is reduced by 1%-6%, the residual polarization sensitivity is 0.4%, and the measurement accuracy of the ocean remotely sensed water radiation can be improved by.6). The polarization response characteristic test system of the instrument is set up. The polarization response amplitude and phase angle of the project prototype of the visible light / near infrared imaging spectrometer are measured. They are the spectral channels and the field of view. The average value of polarization sensitivity of the function.980nm band of the pixel is 4.69% and the average value of the 413nm band is 1.88%. 14 spectral channel * 1024 field pixel polarization response parameter lookup tables are generated, which provides a reference for the instrument on orbit polarization correction.

【学位授予单位】：中国科学院研究生院(上海技术物理研究所)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P715.7

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