Planar Region Detection and Motion Recovery

This paper presents a means of segmenting planar regions from two views of a scene using point correspondences. The initial selection of groups of coplanar points is performed on the basis of conservation of two five point protective invariants (groups for which this invariant is conserved are assumed to be coplanar). The correspondences for four of the five points are used to define a projectivity which is used to predict the change in position of other points assuming they lie on the same plane as the original four. A distance threshold between actual and predicted position is used to find extended planar regions. If two distinct planar regions can be found then a novel motion direction estimator suggests itself.