Ren Huazhong, Liu Rongyuan, Yan Guangjian, Li Zhao-Liang, Qin Qiming, Liu Qiang, Nerry Françoise
Opt Express. 2015 Apr 6;23(7):A346-60. doi: 10.1364/OE.23.00A346.
Land surface emissivity is a crucial parameter in the surface status monitoring. This study aims at the evaluation of four directional emissivity models, including two bi-directional reflectance distribution function (BRDF) models and two gap-frequency-based models. Results showed that the kernel-driven BRDF model could well represent directional emissivity with an error less than 0.002, and was consequently used to retrieve emissivity with an accuracy of about 0.012 from an airborne multi-angular thermal infrared data set. Furthermore, we updated the cavity effect factor relating to multiple scattering inside canopy, which improved the performance of the gap-frequency-based models.
地表发射率是地表状态监测中的一个关键参数。本研究旨在评估四种方向发射率模型，包括两种双向反射分布函数（BRDF）模型和两种基于间隙频率的模型。结果表明，核驱动的BRDF模型能够很好地表示方向发射率，误差小于0.002，因此被用于从机载多角度热红外数据集反演发射率，精度约为0.012。此外，我们更新了与冠层内多次散射相关的空腔效应因子，这提高了基于间隙频率的模型的性能。
