Shape retrieval using shape contexts and cyclic dynamic time warping

Belongie et al. used sets of shape contexts for contours at certain landmarks and showed that they offer good results in shape matching. We propose a better selection of landmark points based on a low-pass filtering of the shape contour and consider that shape context at landmarks along the contour form a cyclic sequence. These cyclic sequences can be properly compared by means of Cyclic Dynamic Time Warping, as shown in the paper. Experiments on the MPEG7 CE-Shape-1 and the SQUID Demo databases show that our proposal outperforms the WARP system and Belongie's approach for shape retrieval.