Fig. 1. Light transport model in a two-layer slab medium

Fig. 2. Reflectance comparison of P3 approximation model with Monte Carlo simulation and diffusion approximation. (a) Comparison of P3 equation with Monte Carlo simulation with the same thickness and different absorption coefficients; (b) comparison of the P3 equation with the Monte Carlo simulation and the diffusion equation near the peak, at low absorption coefficient, away from light source; (c) relative error of P3 equation, diffusion equation, and Monte Carlo simulation at low absorption coefficient, away from light source; (d) comparison of the P3 equation with the Monte Carlo simulation and the diffusion equation near the peak, at high absorption coefficient, near light source; (e) relative error of P3 equation, diffusion equation, and Monte Carlo simulation at high absorption coefficient, near light source

Fig. 3. Transmittance comparison of P3 approximate model with Monte Carlo simulation and diffusion approximation. (a) Comparison of P3 equation with Monte Carlo simulation with the same parameters and different thickness; (b) comparison of P3 equation with diffusion equation and Monte Carlo simulation near the peak, at low absorption coefficient, away from light source; (c) relative error of P3 equation, diffusion equation, and Monte Carlo simulation at low absorption coefficient, away from light source; (d) comparison of P3 equation with diffusion equation and Monte Carlo simulation at high absorption coefficient, near light source; (e) relative error of P3 equation, diffusion equation, and Monte Carlo simulation at high absorption coefficient, near light source