Degree of polarization model based on a modified three-component pBRDF.

The polarized bidirectional reflectance distribution function (pBRDF) model not only can quantify the radiation intensity, but also can effectively describe the polarization characteristics of the scattered light on the target surface. In this paper, a modified three-component pBRDF model is proposed, which considers the reflection process to be composed of specular reflection, multiple reflection, and volume scattering. Key parameters such as the distribution of the microfacet, geometrical attenuation factor, multiple reflection, and volume scattering, are modified. The degree of polarization model is derived based on the new pBRDF, when the incident light is natural light. The degree of polarization of four coating fabric samples is measured by a multi-angle polarization instrument, and the undetermined coefficients in the model are inverted based on the experimental data. A comparison of the measured and modeled results at a wavelength of 720 nm reveals that the model can accurately describe the spatial distribution of polarization characteristics of four samples and control the errors within 0.06, 0.1, 0.04, and 0.09, which provides a theoretical basis for polarization detection and polarization image simulation.