User-Guided Shape from Shading to Reconstruct Fine Details from a Single Photograph

Many real objects, such as faces, sculptures, or low-reliefs are composed of many detailed parts that can not be easily modeled by an artist nor by 3D scanning. In this paper, we propose a new shape from shading (SfS) approach to rapidly model details of these objects such as wrinkles and reliefs of surfaces from one photograph. The method first determines the surface’s flat areas in the photograph. Then, it constructs a graph of relative altitudes between each of these flat areas. We circumvent the ill-posed problem of shape from shading by having the user set if some of these flat areas are a local maximum or a local minimum; additional points can be added by the user (e.g. at discontinuous creases) – this is the only user input. We use an intuitive mass-spring based minimization to determine the final position of these flat areas and a fast-marching method to generate the surface. This process can be iterated until the user is satisfied with the resulting surface. We illustrate our approach on real faces and low-relief photographs.