摘要
敦煌校正场是我国最重要的辐射校正场,地面目标的方向反射特性是影响场地定标精度的重要参数。对于在什么情况下需要校正地表反射率及采用哪种双向反射分布函数(BRDF)进行校正,尚无明确的研究。由于中等分辨率成像光谱仪(MODIS)精度较高,对MODIS影像进行了分析。首先利用2020年9月敦煌场地6组不同测量时刻下的无人机多角度观测数据,分别以6种不同核函数组合方式建立36个不同的BRDF模型,针对不同观测角度下的MODIS影像,分别计算BRDF校正前和BRDF校正后的表观反射率;而后与卫星实测表观反射率进行相对偏差的比较。实验结果表明,以28°的观测角度为界,当观测角度大于28°时相对偏差较大,且BRDF校正对结果的影响较大;在所建立的BRDF模型中,采用接近卫星过境时刻测量的多角度观测数据所建立的BRDF模型校正效果更好;且基于Rossthick-Lidense、RossThick-LiSparseR和Rossthin-LisparseR这三种核函数组合方式的BRDF模型所计算的表观反射率与卫星观测值的相对偏差都比较小。
The Dunhuang correction site is the most important radiation correction site in China,and the directional reflection characteristic of the ground target is an important parameter affecting the site calibration accuracy.Until now,there are no clear studies on circumstances that necessitate the ground reflectance correction,and which bidirectional reflectance distribution function(BRDF)is used for correction.Due to the high accuracy of medium-resolution image spectrometer(MODIS),MODIS images are analyzed.First,using six sets of unmanned aerial vehicle multi-angle observation data under different sun zenith angles at the Dunhuang site in September 2020,36 different BRDF models are established by six different kernel function combinations.For the images under different observation angles,we calculated the apparent reflectance before and after the BRDF correction and compared the relative deviation with the measured apparent reflectance of the satellite.By considering the observation angle of 28°as the boundary,the experimental results show that the relative deviation is greater when the angle is greater than 28°,which is a significant consequence of the BRDF correction.Among the BRDF models established above,the BRDF model established using multi-angle observation data measured close to the time of satellite transit has a better correction effect.Furthermore,the relative deviation between the apparent reflectance calculated by the BRDF model using the kernel function combination of Rossthick-Lidense or RossThick-LiSparseR or Rossthin-LisparseR and the satellite observation value are small.
作者
豆新格
潘军
高海亮
王凯司
孙晗
姜鹏
Dou Xinge;Pan Jun;Gao Hailiang;Wang Kaisi;Sun Han;Jiang Peng(College of Geoexploration Science and Technology,Jilin University,Changchun 130012,Jilin,China;The Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100094,China)
出处
《激光与光电子学进展》
CSCD
北大核心
2022年第16期438-447,共10页
Laser & Optoelectronics Progress
基金
国家重点研发计划(2018YFB0504800,2018YFB0504803)。
关键词
遥感
双向反射分布函数模型
反射率基法
敦煌辐射校正场
表观反射率
remote sensing
bidirectional reflectance distribution function model
reflectance-based method
Dunhuang radiation correction field
apparent reflectance
