Modeling of diffuse reflectance for a two layered medium: A Monte-Carlo study

A simple exponential model of diffuse reflectance for a two-layered medium was developed theoretically based on Monte Carlo simulation. Absorption and reduced scattering coefficients of these two layers were chosen to be different in which scattering property was dominant and the reduced albedo of the upper layer ranged from 0.8 to 0.99 and from 0.93 to 0.98 for the lower layer. Furthermore, the refractive index and anisotropy factor of these two layers were assumed to be equal 1.4 and 0.9 respectively. On the other hand, a finite element method was used to solve a diffusion approximation via COMSOL Multiphysics environment to compare the developed model with a diffusion approximation. The presented model has shown a low relative error, which did not exceed 20%. That was lower than the diffusion approximation results and it was in accordance with another complicated model developed by another research group. Consequently, the robustness of the presented model makes it more likely to predict a reflectance and reproduce the model to estimate a top layer thickness in real-time.