Shape Invariants and Principal Directions from 3D Points and Normals

ABSTRACT A new technique for computing the differential invariants of a surface from 3D sample points and normalsis presented. It is based on a new conformal geometric approach to computing shape invariants directly from the Gauss map. In the current implementation we compute the mean curvature, the Gauss curvature,and the principal curvature axes at 3D points reconstructed by area-based stereo. The differential invariants are computed directly from the points and the normals without prior recovery of a 3D surface model andan approximate surface parameterization. The technique is stable computationally