星载成像仪观月数据提取和辐照度转换方法研究  

Data collection and irradiance conversion of lunar obsevation for MERSI

作　　者：吴荣华 张鹏[1] 郑小兵 胡秀清 徐娜[3] 张璐[3] 乔延利 WU Rong-hua;ZHANG Peng;ZHENG Xiao-bing;HU Xiu-qing;XU Na;ZHANG Lu;QIAO Yan-li(Anhui Institute of Optics and Fine Mechanics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;University of Chinese Academy of Sciences,Beijing 100049,China;National Satellite Meteorological Centre,Beijing 100081,China)

机构地区：[1]中国科学院合肥物质科学研究院安徽光学精密机械研究所,安徽合肥230031 [2]中国科学院大学,北京100049 [3]国家卫星气象中心,北京100081

出　　处：《光学精密工程》2019年第8期1819-1827,共9页Optics and Precision Engineering

基　　金：国家重点研发计划资助项目(No.2018YFB0504900);国家自然科学基金资助项目(No.41471303)

摘　　要：为了实现星载成像仪的月球绝对辐射定标,在轨对月观测数据的预处理环节需要完成两方面的任务:一是从全部的冷空视场数据中,准确判识出月亮进入冷空视场的时刻;二是将对月观测原始计数值换算为全圆盘辐照度,以便与月球辐射模型比较。具体到中分辨率光谱成像仪(MERSI),本文从MERSI观测模式出发构建出月亮进入冷空视场的阈值判识模型。根据MERSI对月观测的成像几何和定标公式,分别以单探元多帧扫描图像和多探元单帧扫描图像为基础,构建出月球全圆盘辐照度算法。结果显示,阈值判识模型可以实现从平均约30 d的观测数据中,准确标记出约1 min的月亮图像数据。两种计算辐照度的方法得到的辐照度平均差异约0.9%。所提方法可以将原始的对月观测数据计算为辐照度值,为进一步的绝对辐射定标及误差分析提供基础,同时,也可以为类似的成像遥感器的月亮定标工作提供参考。Lunar calibration is an effective method for visible and near-infrared spectrum remote sensors.Original lunar observation data should be pre-processed into lunar full disk irradiance in order to compare them with a lunar radiation model.This paper describes the pre-processing of lunar data of the MERSI on the FY-3 Dsatellite.The data pre-processing includes two steps.First,the lunar observation data are identified from the massive space view data.Then,the identified lunar original digital count is converted into full disk irradiance.Based on the MERSI observation mode,the lunar zenith and azimuth in the instrument reference coordinate system are used to construct a threshold model.When the zenith and azimuth meet the threshold conditions,the data are identified as lunar image.According to MERSI's imaging geometry and calibration formula,the lunar full disk irradiance can be calculated from two different lunar images.Irradiance from a single-detector multi-scan image needs to be corrected for the over-sample factor,and irradiance from a multi-detector single-scan image needs to be corrected for the radiation response difference between detectors.Based on this method,about 1 minute of lunar observation data among 30 days can be found and identified.The results show that the average difference of irradiance between the two methods is about 0.9%.The pre-processing method presented in this paper can find the original lunar observation data and convert them to full disk irradiance value,which provides a basis for further absolute radiation calibration and error analysis.It can also provide a reference for lunar calibration of other similar remote sensors.

关 键 词：月球定标 中分辨率光谱成像仪 星载成像仪 月球辐照度 过采样 

分 类 号：TP73[自动化与计算机技术—检测技术与自动化装置]