Single-shot high-quality facial geometry and skin appearance capture

We propose a new light-weight face capture system capable of reconstructing both high-quality geometry and detailed appearance maps from a single exposure. Unlike currently employed appearance acquisition systems, the proposed technology does not require active illumination and hence can readily be integrated with passive photogrammetry solutions. These solutions are in widespread use for 3D scanning humans as they can be assembled from off-the-shelf hardware components, but lack the capability of estimating appearance. This paper proposes a solution to overcome this limitation, by adding appearance capture to photogrammetry systems. The only additional hardware requirement to these solutions is that a subset of the cameras are cross-polarized with respect to the illumination, and the remaining cameras are parallel-polarized. The proposed algorithm leverages the images with the two different polarization states to reconstruct the geometry and to recover appearance properties. We do so by means of an inverse rendering framework, which solves per texel diffuse albedo, specular intensity, and high-resolution normals, as well as global specular roughness considering the subsurface scattering nature of skin. We show results for a variety of human subjects of different ages and skin typology, illustrating how the captured fine-detail skin surface and subsurface scattering effects lead to realistic renderings of their digital doubles, also in different illumination conditions.