Shape and motion measurement of time-varying three-dimensional objects based on spatiotemporal fringe-pattern analysis

Abstract

A method and tools recently applied in animation are presented, and the associated problems connected with combining the real and the virtual world are described. Approaches include creating computer graphics libraries of realistic 3-D objects and describing their animation in 3-D space. The presented method simplifies the process of virtual-object generation and provides the shape and movement of the monitored object. Optical structured-light methods supported by photo- grammetry are proposed for gathering the information about a shape, deformations of shape, and shifts of 3-D objects. The authors apply the spatiotemporal approach, in which the spatial analysis of fringe pattern delivers information about the shape of the object, while the temporal analysis of the intensity variation l(t) at a given pixel provides information about shape variations and out-of-plane displacement. The function I(t) is analyzed by the Fourier-transform method. Rigid-body motion of the object is determined by a photogrammetry-based marker tracking method. The methodology of measurement is presented, together with experimental results.