Correspondence of coplanar features through p2-invariant representations

The correspondence between two coplanar sets of points (or lines) is established making use of a novel invariant representation of five-tuples of features. The projective/permutation (p²) invariants are insensitive to the order of the features in the computation and thus provide a significant speedup in matching. Performance degradation due to the noise sensitivity of the invariants is avoided by using context independent constraints (noncollinearity of points, preservation of the convex hull); and by accumulating the feature correspondence hypotheses in a contingency table. Full projective correspondence can be recovered reliably for positional uncertainty of several pixels or in the presence of outliers