Modeling repetitive motions in real-world 3D scenes

Obtaining models of dynamic 3D objects is an important part of content generation for computer graphics. If the states or poses of the dynamic object repeat often during a sequence (but not necessarily periodically), we call such a repetitive motion. There are many objects, such as toys, machines, and humans, undergoing repetitive motions. Our key observation is that for repetitive motions we can use one fixed camera to perform robust motion analysis and a second capture-device to provide 3D information of each motion state. After the motion sequence, we group temporally disjoint observations of the same motion state and produce a smooth space-time reconstruction of the scene. Effectively, the dynamic scene modeling problem is converted to a series of static scene reconstructions, which are much easier to tackle. The second device can be either a passive camera or an active-light projector, resulting in two different modeling techniques. Based on this observation, we present an efficient passive multi-viewpoint acquisition and a robust structured-light acquisition of repetitive motions.