From image quadrilaterals to symmetrical trapezia

摘要

This paper concerns the 3-D interpretation of image quadrilaterals as the perspective projections of bilateral symmetric trapezia. Simple algorithms are described for reconstructing a symmetric trapezium from a given image quadrilateral, and for determining the 3-D motion of a symmetric trapezium from two matched image quadrilaterals. Several results are established and/or further verified, including the Necker reversal ambiguity in the interpretation of image quadrilaterals as the perspective projection of bilateral symmetric trapezia. Experiments with both synthetic and real images are included to demonstrate the validity of the theoretic results.