理想光滑表面具有很强的偏振特性,但实际表面通常较为粗糙,造成遮蔽效应明显和漫反射严重。为准确表征粗糙表面偏振特性,基于微面元模型,综合考虑遮蔽效应和漫反射情况下,建立一种改进的六参量偏振双向反射分布函数(pBRDF)模型,在此基础上推导出粗糙表面光学反射偏振度表达式。对铝和黑漆材料的偏振度进行模型仿真,反演其复折射率。结果表明,所提模型仿真值与实验测量值更加吻合,复折射率反演精度更高。对45#钢材料开展pBRDF测量,分析了不同入射角、反射角、粗糙度下偏振度的分布。实验结果表明,六参量模型仿真值与实验测量值均能较好地吻合,通过对漫反射部分建模增加了模型的准确性。该研究可为粗糙表面的探测和分析提供理论基础和方法。

The ideal surface has strong polarization properties, but the actual surface is usually rough, resulting in significant shadowing and severe diffuse reflection. In order to accurately characterize the polarization properties of rough surfaces, based on the micro-facet model, an improved six-parameter polarization bidirectional reflection distribution function (pBRDF) model is established considering the shadowing effect and diffuse reflection. Based on this, the expression of the optical reflection polarization degree of rough surface is derived. The degree of polarization of aluminum and black lacquer materials is simulated to invert the complex refractive index. The results show that the proposed model simulation value is more consistent with the experimental measurement value, and the complex refractive index inversion accuracy is higher. The pBRDF measurement is carried out on the 45# steel material, and the distribution of polarization degrees under different incident angles reflection angles and roughness is analyzed. The experimental results show that the simulation values of the six-parameter model can be well matched with the experimental measurements, and the accuracy of the model is increased by modeling the diffuse reflection part. This work can be used as a theoretical basis and method for the detection and analysis of rough surfaces.