Abstract The traditional feature points only reflect some information of the contour curve. To describe the curve more accurately, a kind of feature points, nameed chord height point, is defined and extracted. Based on the feature points, a local curve descriptor is constructed to match the contour curves. Chord height point is sampled from each sub-curve and it can be employed to describe the curve more precisely than the common feature points such as corners, points of tangency and inflection points. It can solve the problem that the curve can not be described precisely, because the smooth curve has fewer feature points. The defined chord height points and the constructed recognition vector are local descriptors with invariance under affine transformation, so the matching method is robust under occlusion and affine transformation. The theory analysis and experimental results show that the proposed algorithm is effective.
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