Invariant Signatures of Closed Planar Curves
We prove that any subset of a"e(2) parametrized by a C (1) periodic function and its derivative is the Euclidean invariant signature of a closed planar curve. This solves a problem posed by Calabi et al. (Int. J. Comput. Vis. 26:107-135, 1998). Based on the proof of this result, we then develop some cautionary examples concerning the application of signature curves for object recognition and symmetry detection as proposed by Calabi et al.
signature object recognition symmetry symmetry detection closed curves phase portrait