在轨辐射定标包括相对辐射定标和绝对辐射定标, 它是提高遥感数据定量化精度的关键步骤和重要方法。本文阐述了基于均匀场地分区综合的相对辐射定标方法、基于反照率的绝对辐射定标方法及其基本原理, 并首次将其应用于“天绘一号”卫星上的高分辨、多光谱和三线阵相机的辐射定标中。研究结果表明, 相对辐射定标过程去除了卫星图像的条带噪声, 且保存了图像细节;然后, 使用反照率基法, 通过在敦煌场地铺设灰阶靶标, 测量卫星过顶时的地物目标反射率光谱和大气信息, 对“天绘一号”卫星传感器进行了绝对辐射定标;最后, 使用辐射定标结果来反演地物反射率, 与实测的地物反射率相比误差小于5%, 验证了在轨辐射定标系数的有效性。
On orbit radiometric calibration means relative radiometric calibration and absolute radiometric calibration, it is a critical process and important method for improving the resolution of quantitative study of remote sensing data. In this paper, methods and principles of regional synthesized uniform fi eld based relative radiometric calibration and albedo based absolute radiometric calibration, are introduced. It is the fi rst time to use the above methods for the calibration of the three cameras such as high resolution camera, high multispectral camera and triplet linear array camera on Mapping Satellite-1. Results show that, the braid noise is removed effectively by the process of relative radiometric calibration. Then, the absolute radiometric calibration for Mapping Satellite-1 sensors are also performed through Dunhuang fi eld radiation target, the atmospheric parameters and the ground object spectral refl ectivity. Results show that, the difference between the refl ectivity of ground object obtained by the satellite sensors and that of fi eld measured value is less than 5%, which demonstrated the effectiveness of on orbit radiometric calibration coeffi cient.