Shape retrieval using normalized Fourier Descriptors based signatures and cyclic Dynamic Time Warping

The WARP system defines a dissimilarity measure between shapes described by their contours which is based on Dynamic Time Warping of Fourier Descriptors based signatures. These signatures are invariant to translation, scaling, rotation, and selection of the starting point. However, identical shapes present ambiguous signatures and similar shapes may yield significantly different signatures. Differences affect rotation and starting-point of the signatures, which may lead to poor performance in classification and shape retrieval tasks. We propose a different signature method to provide true rotation invariance and a Cyclic Dynamic Time Warping dissimilarity measure to achieve true starting-point invariance in shape comparisons.