以2007年4月26日北京地区TM图像为例,对美国地质调查局(USGS)和中国遥感卫星地面站(RSGS)提供的传感器辐射定标参数进行精度评价。首先,根据不同来源的辐射定标参数,采用对应的定标系数计算公式得到相应的定标系数,采用不同的定标系数分别对DN值进行反演,得到不同辐射定标参数下的表观辐亮度数据;然后,将两种表观辐亮度反演结果输入FLAASH大气校正模型,反演图像获取时的气象视距和地表反射率;最后,通过同步气溶胶观测数据和高分辨率遥感影像对所反演的气象视距和地表反射率分类精度进行评价,得到传感器定标参数精度评价结果。研究表明:USGS提供的辐射定标参数能更为精确地反映TM传感器的辐射特征。
The radiometric calibration parameter is very important in quantitative application of remote sense data. In this paper, the Landsat Thematic Mapper Data of Beijing acquired in April 26, 2007 were applied to evaluating the radiometric calibration parameters supplied by USGS and RSGS. First, the radiance data were computed respectively with the calibration coefficients converted from calibration parameters. Second, the FLAASH atmosphere correction model was used to compute meteorological range and surface reflectance. Third, according to the aerosol observation data from AERONET and high resolution remote sensing image, the accuracy evaluation results of the two radiometric calibration parameters were obtained on the basis of the accuracy of meteorological range and classification of surface reflectance. The results show that parameters supplied by USGS can reflect radiometric features of TM sensor more accurately.