Modeling And Simulation Of Spectral Polarimetric BRDF Of Rough Surface

Under normal conditions, it is difficult to find the target when its color is the same as background scene. However, the polarized state of the reflected light are different because the dielectric coefficient, roughness, surface microstructure are different, so it is better than other methods that detecting target with polarized light. The significant of reflect light is also changed under different wavelength, so detecting targets with polarized light under different wavelength has many advantage. The BRDF is used to describe the reflected light in hemisphere space. But traditional BRDF models are not applicable with polarized light and changed wavelength, so it is necessary to build a new BRDF model.Aiming at these problems, in order to establish the polarization spectrum BRDF models, this thesis regards the wavelength as a major factor in BRDF model. The main work is as follows:(1) Build the polarimetric BRDF model based on Kirchhof theory, the complex refractive index and the root mean square roughness wavelength dependent functions are established respectively. The real part of the complex refractive index of the rate of parts expands in series of wavelength, the undetermined parameter in the function can be got by measuring the refractive index under different wavelengths; the absorption coefficient is transformed as a function of the extinction coefficient and wavelength. The roughness function can be got by using the relationship between the wavelength, reflectivity and mean square root of roughness. At last, combining two function with the polarimetric BRDF model, the spectral polarimetric BRDF is obtained.(2) According to the undetermined parameter of the refractive index spectral model, the polarization spectral model of aluminum and plastic is obtained. The polarization degree spectrum curves of aluminum and plastic are emulated under the condition of natural incident light and polarized incident light separately, and the wavebands where the most significant change in the degree of polarization are identified by analyzing the curves.(3) The model of this thesis and the ray tracing technology are combined to realize polarization ray tracing system. Analyzing the polarization degree spectrum curves of aluminum and plastic and choosing the wavebands where the most significant change in the degree of polarization to do the polarized light tracing. The accuracy of the model is verified by comparison the polarization degree spectrum curves and the polarization degree images of different polarization directions of multiple wavelengths, and the results show that the polarization spectral model has certain guiding significance in the choice of detection wavelength.