Reiner Lenz, Peter Meer
Point Configuration Invariants under Simultaneous Projective and Permutation Transformations
Abstract:The projective invariants used in computer vision today are permutation sensitive
since their value depends on the order in which the features were
considered in the computation. We derive, using tools from representation
theory, the projective and permutation (p2) invariants of the four collinear
and the five coplanar points configurations. The p2-invariants are insensitive
to both projective transformations and changes in the labeling of
the points. When used as model database indexing functions in object
recognition systems the p2-invariants yield a significant speedup.
Keywords: projective invariants, permutation invariants, feature indexing,
object recognition