FROM IMAGE QUADRILATERALS TO SYMMETRICAL TRAPEZIA

This paper concerns the 3-D interpretation of image quadrilaterals as the perspective projections of bilateral symmetric trapezia. Simple al gorithms are described for reconstructing a symmetric trapezium from a given image quadrilateral, and for determining the 3-D motion of a sy mmetric trapezium from two matched image quadrilaterals. Several resul ts are established and/or further verified, including the Necker rever sal ambiguity in the interpretation of image quadrilaterals as the per spective projection of bilateral symmetric trapezia. Experiments with both synthetic and real images are included to demonstrate the validit y of the theoretic results. (C) 1998 Published by Elsevier Science Ltd on behalf of the Pattern Recognition Society. All rights reserved.