IMAGE DESCRIPTION AND 3-D RECONSTRUCTION FROM IMAGE TRAJECTORIES OF ROTATIONAL MOTION

This paper presents a new technique for reconstructing the 3-D structure and motion of a scene undergoing relative rotational motion with respect to the camera. Given image correspondences of point features tracked over many frames, a two-stage technique for reconstruction is presented. First, a grouping algorithm that exploits spatio-temporal constraints of the common motion to achieve a reliable description of discrete point correspondences as curved trajectories (general conics in the case of rotational motion) in the image plane is developed. In contrast, trajectories fitted to points independent of each other lead to arbitrary image descriptions and very inaccurate 3-D parameters. Second, a new closed-form solution, under perspective projection, for the 3-D motion and location of points from the computed image trajectories is presented. Both stages are applied to real image sequences with good results. This approach represents a first step in a longer-term research effort examining the role of explicit spatio-temporal organization in the interpretation of scenes from dynamic images.