摘要
大气校正是遥感数据定量化应用的关键步骤,国产环境与灾害监测预报小卫星星座(简称HJ-1)CCD相机数据在进行大气校正时,面对数据量大、观测角度变化大、气溶胶多变等各种问题。本文针对HJ-1CCD相机的波段特征,利用Hsu等提出的深蓝算法借助地表反射率库反演得到气溶胶光学厚度,结合辅助角度数据计算观测几何,利用核驱动模型完成了BRDF校正,提出了针对HJ-1CCD数据的在植被、裸土等地表类型通用的大气校正算法;在数据处理中,采用查找表和双线性插值的方法分块计算HJ-1CCD图像的大气参数,利用IDL语言的矩阵运算大大加快了大气校正速度,实现了快速大气校正。以2012年7月3日过境中国华北平原的1景CCD数据进行了算法实验,结果表明,该算法较好的校正了大气对地表反射率的影响,能够在8min内快速完成1景数据量约为1G的CCD数据的大气校正,校正后的土壤和植被等典型地物的反射率更接近其光谱特征;同时,将校正结果与同期过境的MODIS地表反射率产品进行了比对,由于分辨率的较高,HJ-1的结果细节表现要优于MODIS,而二者获得的典型地物反射率相关性较好(相关系数大于0.9)。误差分析表明,气溶胶类型的误判会对近红外波段地表反射率带来较大的误差,在0.05左右,而地表反射率库0.02的误差,会对红波段和绿波段的大气校正结果带来0.01左右的误差。
In the present ,for the characteristic of HJ-1 CCD camera ,after receiving aerosol optical depth （AOD） from deep blue algorithm which was developed by Hsu et al .assisted by MODerate-resolution imaging spectroradiometer （MODIS） surface re-flectance database ,bidirectional reflectance distribution function （BRDF） correction with Kernel-Driven Model ,and the calcula-tion of viewing geometry with auxiliary data ,a new atmospheric correction method of HJ-1 CCD was developed which can be used over vegetation ,soil and so on .And ,when the CCD data is processed to correct atmospheric influence ,with look up table （LUT） and bilinear interpolation ,atmospheric correction of HJ-1 CCD is completed quickly by grid calculation of atmospheric parameters and matrix operations of interface define language （IDL） .The experiment over China North Plain on July 3rd ,2012 shows that by our method ,the atmospheric influence was corrected well and quickly （one CCD image of 1 GB can be corrected in eight minutes） ,and the reflectance after correction over vegetation and soil was close to the spectrum of vegetation and soil .The comparison with MODIS reflectance product shows that for the advantage of high resolution ,the corrected reflectance image of HJ-1 is finer than that of MODIS ,and the correlation coefficient of the reflectance over typical surface is greater than 0.9 .Error analysis shows that the recognition error of aerosol type leads to 0.05 absolute error of surface reflectance in near infrared band , which is larger than that in visual bands ,and the 0.02 error of reflectance database leads to 0.01 absolute error of surface reflec-tance of atmospheric correction in green and red bands .
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2014年第3期729-734,共6页
Spectroscopy and Spectral Analysis
基金
遥感科学国家重点实验室开放基金项目(OFSLRSS201301)
国家青年科学基金项目(41301358)
高分辨率对地观测系统重大专项(05-Y30B02-9001-13/15)
国家重点基础研究发展计划(973)项目(2010CB950801)资助
关键词
遥感
大气校正
HJ-1
IDL
IDL
Remote sensing
Atmospheric correction
IDL
