Dp. Mukherjee et al., SHAPE FROM SYMMETRY - DETECTING AND EXPLOITING SYMMETRY IN AFFINE IMAGES, Philosophical transactions-Royal Society of London. Physical sciences and engineering, 351(1695), 1995, pp. 77-106
We investigate the constraints placed on the image projection of a pla
nar object having local reflectional symmetry. Under the affine approx
imation to projection, we demonstrate an efficient (low-complexity) al
gorithm for detecting and verifying symmetries despite the distorting
effects of image skewing. The symmetries are utilized for three distin
ct tasks: first, determining image back-projection up to a similarity
transformation ambiguity; second, determining the object plane orienta
tion (slant and tilt); and third, as a test for non-coplanarity amongs
t a collection of objects. These results are illustrated throughout wi
th examples from images of real scenes.