" Light scattering in translucent layers: angular distribution and internal reflections at flat interfaces" by Arthur Gautheron

Seminar by Arthur Gautheron

Abstract

Optical characterization and appearance prediction of translucent materials is required in various fields such as dental restorations or 3D printing technologies. However, flux transfer models like the Kubelka-Munk model (2-flux) fail to predict the color variations of translucent objects when their thickness varies. Indeed, they rely on the assumption that the angular distribution of light is Lambertian at any depth within the material, i.e. also at the bordering interfaces of the object. The internal front and back reflectances are therefore typically computed assuming a Lambertian angular distribution.

In this talk, the Radiative Transfer Equation, allowing a more accurate description the scattering of light across a layer of translucent material, is used to investigate this point. It turns out that the angular distributions of light are far from being Lambertian, due to the combined effect of light scattering and Fresnel’s reflection. Consequently, the internal reflectances may significantly vary according to the layer’s thickness, refractive index, scattering and absorbing coefficients. This work enables to better understand the scattering of light inside a translucent layer, and invites to revisit the well-known Saunderson correction usually used in 2-flux or 4-flux models.

This seminar will be held in english.