基于环境星CCD数据的山区大气校正研究

Atmospheric Correction in Mountainous Areas Based on Environmental Satellite CCD Images

山区地形崎岖,高程变化较大,遥感影像地形效应明显,地物的光谱特征容易受到干扰,导致在分类过程中对遥感影像出现误分,不利于遥感信息的提取。基于辐射传输原理,利用Python开发了针对山区的大气校正算法。所提算法充分考虑了太阳直接辐射、天空散射辐射及邻近地表反射辐射对卫星入瞳处目标辐亮度的影响,可以有效地消除地形阴影的影响。利用所提算法,结合数字高程模型(DEM),对环境减灾二号01组卫星的CCD传感器的山区数据进行大气校正研究。分析结果表明:校正后的图像地形效应减弱,图像质量得到了明显的改善,反演得到的地表反射率与实地测量的地物光谱数据比较吻合,为进一步开展定量遥感研究提供了数据质量保障。

Mountainous areas have rough terrain and substantial elevation changes.The topography effect of remote sensing images significantly interferes with the spectral characteristics of ground objects and may lead to the misclassification for remote sensing images,which is not conducive to remote sensing information extraction.Based on the principle of radiative transfer,an atmospheric correction algorithm for mountainous areas is developed using Python.The proposed algorithm considers the influence of direct solar,sky scattered,and adjacent surface reflected radiations on the target radiance at the satellite entrance pupil and can effectively eliminate the terrain shadow influence.We conducted the atmospheric correction of the CCD sensor for mountain area data of HJ2AB(a small satellite for environmental and disaster monitoring and prediction made in China)using the proposed algorithm and digital elevation model(DEM).The analysis results show that the terrain effect of the corrected image is weak and that the image quality improves significantly.The surface reflectance obtained by inversion agrees with the spectral data of the ground objects measured in the field,which provides a data quality guarantee for further quantitative remote sensing research.