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基于BRDF大气订正环的途径和核驱动模型 ,用MODTRAN创建大气参数查找表 (LookUpTable LUT) ,加入地表先验知识 ,对AMTIS(AirborneMulti angleTIR/NIRImagingSystem AMTIS)的可见光、近红外波段数据进行了大气订正 ,并根据地面数据进行了验证。结果表明 ,采用本文算法比基于地表朗伯假定的大气订正能更有效地去除大气影响
To extract quantitative information from the remote sensed imagery accurately, atmospheric correction that decoupled the surface spectral signature and the aerosol scattering effect is a necessary step. There are several models to describe the multiple bouncing between the surface and atmosphere. But when viewing only from a single direction, we can't get the enough information such as the albedo of surface to decouple the surface signature and aerosol scattering from these models, so a lambert surface has to be assumed and large error may be introduced in the atmospheric correction when the ground is non-lambertian. This paper describes the atmospheric correction algorithm of AMTIS for the VIS/NIR bands. The algorithm is based on a BRDF Loop approach and MODTRAN4.1 is applied to calculate the atmosphere parameters used in the atmospheric correction. The parameters used to decouple the multi-bouncing effect such as direct-hemisphere albedo and hemisphere-direct albedo are estimated in the loop process. The BRDF model for calculating albedo is a kernel driven model. To accelerate the atmospheric correction, all the atmospheric parameters used in this algorithm are pre-computed with MODTRAN4.1 and saved in the Look-up Table. Pri-or knowledge is used in the retrieval of kernel-driven model when the prior multi-angle sampling is not enough. The atmospheric correction result is validated using the synchronous ground experiment. The atmospheric correction result shows that this algorithm can wipe off the atmospheric smoothing effect and the BRDF shape of ground surface is reversed effectively.