We have developed a system to measure both the optical properties of facial skin and the three-dimensional shape of the face. To measure the three-dimensional facial shape, our system uses a light-field camera to provide a focused image and a depth image simultaneously. The light source uses a projector that produces a high-frequency binary illumination pattern to separate the subsurface scattering and surface reflections from the facial skin. Using a dichromatic reflection model, the surface reflection image of the skin can be separated further into a specular reflection component and a diffuse reflection component. Verification using physically controlled objects showed that the separation of the optical properties by the system correlated with the subsurface scattering, specular reflection, or diffuse reflection characteristics of each object. The method presented here opens new possibilities in cosmetology and skin pharmacology for measurement of the skin's gloss and absorption kinetics and the pharmacodynamics of various external agents.
Subsurface scattering gives a distinct look to many everyday objects. However, until now, systems to acquire subsurface scattering have assumed that the subsurface displacement and angle of scattering are completely independent of the angle of incident. While this independence substantially simplifies the acquisition and rendering of materials where it holds true, it makes the acquisition of other materials impossible. In this paper, we demonstrate a system that can quickly acquire the full anisotropic subsurface scattering at a given point. Unlike many existing commercial acquisition systems, our system can be assembled from off-the-shelf optical component and 3D printed/cut parts, making it accessible at a low price. We validate our device by measuring and fitting a dipole model for material exhibiting isotropic subsurface scattering as well as comparing real-world appearance with rendering of anisotropic material under incident laser beam illumination.