FINDING THE MOTION, POSITION AND ORIENTATION OF A PLANAR PATCH IN 3D SPACE FROM SCALED-ORTHOGRAPHIC PROJECTION

For the time being, many methods about how to solve the motion and str ucture of a rigid object in 3D space by using point or line correspond ences have been widely researched. In this paper, the projected 2D ima ge shapes of planar patches in 3D space are used as our basic image fe atures. We try to determine the motion parameters and plane equations of planar patches in 3D space from the relationships among their obser ved image shapes. Besides, scaled-orthographic projection is used inst ead of the original perspective projection because of its simpler and tractable mathematical formulas. Not only a closely-approximate model to perspective projection, it further solves the inherent depth indete rminancy which exists in orthographic projection. Moreover, after appl ying a pre-processing of rotation correction to the original image dat a, our estimation result can achieve a better numerical solution than that without this pre-processing. Simulation experiments show the exce llence of our algorithms in estimating the motion parameters. Ambiguit ies, indeterminancy, and data degeneracy are also carefully discussed in this paper, which provides some important insights to the problems.