Light and Skin Interactions

6.1.2. Scattering Simulation

The H-K model assumes that the reflected radiance from a surface has two components (Figure 6.1). One arises due to surface reflectance (L^rs) and the other due to subsurface volume scattering (L^rv). It also assumes that the transmitted radiance has two components (Figure 6.1). One, called reduced intensity, represents the amount of light transmitted through the layer without scattering inside the layers, but accounting for absorption (L^ri). The other represents the amount of light scattered in the volume (L^tv). Similarly, the BRDF and BTDF also have two components, and the relative contributions of the surface and subsurface terms are modulated by the Fresnel coefficients. Clearly, the variations on the polar angle ...