航天高光谱遥感器CHRIS的水体图像大气校正  

Atmospheric Correction for Waterbody Images Acquired by Spaceborne Hyperspectral Sensor CHRIS

作　　者：申茜[1,2] 张兵[1] 李俊生[1,2] 张霞[1] 张小咏[3] 

机构地区：[1]中国科学院通感应用研究所,遥感科学国家重点实验室,北京100101 [2]中国科学院研究生院,北京100039 [3]中国科学院地理科学与资源研究所,北京100101

出　　处：《测绘学报》2008年第4期476-481,488,共7页Acta Geodaetica et Cartographica Sinica

基　　金：中国科学院知识创新工程重要方向项目(KZCX3-SW-350);国家自然科学基金项目(40671134)

摘　　要：CHRIS(Compact High Resolution Imaging Spectrometer)是欧空局于2001年10月发射的PROBA-1卫星上搭载的探索性高光谱遥感器,它具备高空间分辨率、多角度观测、高光谱成像等特点,为水质遥感监测提供不可多得的数据源。基于卫星遥感图像定量监测水质,一个关键步骤就是进行精确的大气校正,提取水面反射率。相比陆地遥感图像,水面反射率是弱信号,对大气校正的要求更高。6S(Second Simulation of SatelliteSignal in the Solar Spectrum)和MODTRAN(MOderate resolution TRANsmittance code)是两种常用的大气辐射传输模型。本文选取基于6S的REMS(Remote Sensing Environmental Monitoring System)和基于MODT-RAN的ACORN(Atmospheric CORrection Now)两种大气校正软件,对太湖梅梁湾的三景不同成像角度CHRIS图像进行大气校正,将大气校正后的图像水体反射率与地面同步实测水体反射率进行比较分析。结果表明,经过大气校正的CHRIS图像得到的水面反射率与实测反射率波形十分地接近,在全部波长范围内的相关系数达到90%。分析实测的水体反射率角度特征,发现图像的角度特征更明显。三个观测角度下反射率之间的各差值都呈现出在绿光波段较大,在红光和近红外波段偏小的特点,这和实测结果相符。ACORN校正后的图像的角度特征更好地与实测结果吻合。CHRIS（Compact High Resolution Imaging Spectrometer）is an exploring hyperspectral remote sen sor, carried on board PROBA-1 satellite. This satellite was launched in October, 2001 by the European Space Agency. With the properties of high spatial resolution, multiangle observation and hyperspectral imagery, CHRIS offers a precious data resource for monitoring water quality. To monitor water quality by remote sens ing technique quantitatively, a crucial step is to aceomplish atmospheric correction accurately to gain above water reflectance. Compared with remote sensing images over land, water reflectance is a weak signal, which requires more accurate atmospheric correction. 6S （Second Simulation of Satellite Signal in the Solar Spectrum） and MODTRAN （MOderate resolution TRANsmittance code） are tWO widely used radiative transfer models. Most softwares utilize these two models to perform atmospheric correction of remote sensing images. This paper apply two sorts of softwares, including the 6S based REMS（Rcmote Sensing Environmental Moni toring System） and MODTRAN based ACORN（Atmospheric CORrection Now） to remove atmosphere effects over three CHPIS images acquired under different view angles over Meitiang Bay. Taihu Lake. We compared the reflectance spectra extracted from the atmospherically corrected images with in situ measurement. The resuh shows that the water reflectance correeted by REMS and ACORN are quite close to the measured data. The correlation coefficients over thewhole spectral range reach 90%. The angle properties of in situ measured data are analyzed, and the angle properties of corrected images are more obvious than those of in situ observa lion. The difference values of retlectance under the three view angles are bigger in green light than in red and near infrared light, agreeing with the measurement. The angle properties of reflectance corrected by ACORN better correspond with those of measured reflectance.

关 键 词：CHRIS 高光谱 水面反射率 大气校正 

分 类 号：TP751[自动化与计算机技术—检测技术与自动化装置]