Shape from symmetry: detecting and exploiting symmetry in affine images
Dipti Prasad Mukherjee, Andrew Zisserman, Michael Brady · Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences · 1995
Abstract We investigate the constraints placed on the image projection of a planar object having local reflectional symmetry. Under the affine approximation to projection, we demonstrate an efficient (low-complexity) algorithm for detecting and verifying symmetries despite the distorting effects of image skewing. The symmetries are utilized for three distinct tasks: first, determining image back-projection up to a similarity transformation ambiguity; second, determining the object plane orientation (slant and tilt); and third, as a test for non-coplanarity amongst a collection of objects. These results are illustrated throughout with examples from images of real scenes.