Polarimetric bidirectional reflectance distribution function empirical model considering diffuse reflection polarization

The Bidirectional Reflectance Distribution Function (BRDF) with polarization can comprehensively describe surface scattering phenomena. Empirical models excel at simulating complex light scattering phenomena, but existing polarimetric BRDF (pBRDF) empirical models are relatively scarce. This paper proposes an innovative empirical pBRDF model, which is based on the existing five–parameter semi–empirical BRDF framework and incorporates the Mueller matrix to describe polarization scattering characteristics. The Mueller matrix is closely related to the material's complex refractive index (n, k), but its physical properties conflict with the assumptions of pure empirical models. To resolve this contradiction, this paper derives an empirical expression for the Mueller matrix and validates its effectiveness through experiments. The study finds that this expression can successfully simulate the Mueller matrix. During the construction of the polarization model, the traditional view holds that diffuse reflection light does not have polarization. However, this study finds through experiments that diffuse reflection light actually has polarization characteristics. Based on this, the Mueller matrix for diffuse reflection is derived, and a corresponding empirical model is proposed. By comparing the results of this pBRDF model with experimental data from various materials, it is shown that the model's inversion results align well with the experimental data, providing a new reference for the extraction and recognition of target polarization characteristics in the future. It is expected that this model will have wide applications in various fields. Future research will further optimize and expand the model to adapt to a broader range of scenarios.