一种适用于涂层的双高斯偏振BRDF模型

为了更精确地描述涂层类材料的偏振双向反射分布函数，在微面元模型的基础上建立了双高斯偏振BRDF模型并对模型进行了仿真。相对于以往模型，其耦合了强度分布非朗伯的且包含偏振成分的以Rahman-Pinty-Verstraete函数为基础的漫反射。利用基于LCVR的全偏振多谱段成像仪在476 nm波段对白色、哑光白和珍珠白的自喷漆以及普通光盘背面的漆进行了多组面内偏振BRDF测量实验。之后从部分实验数据出发利用最小二乘法对模型参数进行了分步反演，反演结果在多组初值条件下都一致，证明反演得到的参数为全局最小值。最后对获得的模型参数进行仿真，结果表明模型对强度值和偏振度值符合都很好，尤其是能够符合漫反射的偏振。该模型对物质分类及识别以及场景仿真具有一定的实用意义。

Double-Gauss polarimetric BRDF model of painted surfaces

In order to describe the polarized bidirectional reflectance distribution function of the paint material more accurately, a double-Gauss polarized bidirectional reflectance distribution function(BRDF) was modeled and simulated which based on the micro-facet assumption. Relative to the previous models, it contained non-Lamb and polarized diffuse reflection based on Rahman-Pinty-Verstraete function. Several experiment groups of polarized BRDF in the plane of incidence of painted surfaces, such as white, matte white, pearl white paint, and the paint on the back of a cd, were measured by the polarization multi-spectral imagery based on Liquid Crystal Variable Retarders(LCVR) at 476 nm. Then, the parameters of model were inversed step by step using the least square method from some experimental data. The inversion results were consistent under many initial conditions, which indicated the obtained parameters were the global minimum. Finally, the model parameters obtained were simulated. The simulation results prove that the simulated intensity and DOP of reflection of painted surfaces fit in the measured appropriate values very well, especially for the polarized diffuse reflection. This model can be applied in classification and recognition of material and scene simulation.