为提高地物光谱模拟精度, 建立地表混合光谱模型, 利用ASD FieldSpec3 Hi-Res便携式地物光谱仪和地物多角度二向性反射平台, 设计试验探测不同角度下的不同叶片覆盖面积的混合光谱。 以等距离/等面积模型为理论基础, 将模型中二维权重系数变化规律扩展到三维空间权重系数变化中, 考虑探测方向倾斜时探测区域权重系数的变化, 提出新的考虑几何角度的三维权重模型对混合光谱进行模拟, 并与实测混合光谱对比分析。 分析结果表明, 相比于等距离/等面积模型, 三维权重模型对探测区域进行了细分, 提高了权重系数计算精度, 模拟的混合光谱误差更小, 特别是在探测角度有倾斜时, 模拟的效果更明显, 均方根误差平均降低了0.016 1, 光谱角误差平均降低了0.07。 三维权重模型考虑了探测角度对权重系数的影响, 提高了光谱模拟的精度, 为地表模型的建立及卫星数据混合光谱分解的应用提供新的理论基础。

To improve the accruacy of field hyperspectral simulation and build the field spectral mixture model, the experiments for detecting mixture spectra of different detected angles and different ratios of leaf cover area were conducted to obtain the mixture spectra by using ASD FieldSpec3 Hi-Res field spectrum instrument with the reflex platform. Based on the theory of equidistant/homalographic model, the computation of weight coefficients for the model was expanded to calculation of three-dimensional weight coefficients. Taking account of the impact of zenith angle on weight coefficient, the three dimensional coefficient model was proposed for simulating mixture spectra, and comparing with the measured spectra for analysis. The results showed that the three dimensional coefficient model had more accurate computation of weight coefficient and had smaller error compared to equidistant/homalographic model. Especially for inclined detected angle, it had better simulation that it reduced the error 0.016 1 in RMSE and 0.07 in SAD. The three dimensional coefficient model considered the influence of detected angle, thus enhancing the estimation of mixture spectra and providing a new method for building field mixture model and unmixing mixed spectra from satellite data.