Automatic 3D Model Construction for Turn-Table Sequences

As virtual worlds demand ever more realistic 3D models, attention is being focussed on systems that can acquire graphical models from real objects. This paper describes a system which, given a sequence of images of an object rotating about a single axis, generates a textured 3D model fully automatically. In contrast to previous approaches, the technique described here requires no prior information about the cameras or scene, and does not require that the turntable angles be known (or even constant through the sequence). From an analysis ofthe projective geometry of the situation, it is shown that the rotation angles may be determined unambiguously, and that camera calibration, camera positions and 3D structure may be determined to within a two parameter family. An algorithm has been implemented to compute this reconstruction fully automatically. The two parameter reconstruction ambiguity may be removed by specifying, for example, camera aspect ratio and parallel scene lines. Examples are presented on four turn-table sequences.