Contour-based shape retrieval using dynamic time warping

A dissimilarity measure for shapes described by their contour, the Cyclic Dynamic Time Warping (CDTW) dissimilarity, is introduced. The dissimilarity measure is based on Dynamic Time Warping of cyclic strings, i.e., strings with no definite starting/ending points. The Cyclic Edit Distance algorithm by Maes cannot be directly extended to compute the CDTW dissimilarity, as we show in the paper. We present an algorithm that computes the CDTW dissimilarity in O(mn log n) time, where m and n are the lengths of the cyclic strings. Shape retrieval with the new dissimilarity measure is experimentally compaxed with the WARP system on a standard corpus.