COMPUTATIONAL CROSS RATIO FOR COMPUTER VISION

A new ''computational'' formulation of cross ratio is presented with a view to applications to computer vision problems by extending the fra mework of ''computational projective geometry'' of Kanatani (Image Und erstand. 54, 1991, 333-348). As typical examples, we construct procedu res for computing the 3-D orientation of a planar shape from its 2-D p rojection image and the focus of expansion from an image trajectory of a single point by taking advantage of the perspective invariance of c ross ratio and ''projective coordinates,'' and the resulting 3-D inter pretation of ''harmonic range.'' (C) 1994 Academic Press, Inc.