Rotation and Scale Invariant Shape Description Using the Contour Segment Curvature

This paper presents a shape description method based on contour segment curvature (CSC). The CSC is defined as the ratio of the line length connecting two endpoints of a contour segment to its curve length. To extract consistent contour segment, the concept of overlapped contour segment is introduced. The rotation and scale invariant CSC can be extracted through the use of the overlapped contour segment. The proposed method describes the shape of objects with feature vectors that represents the distribution of the CSC, and measures the similarity by comparing the feature vector acquired from the corresponding unit-length segment. The experimental results show that the proposed method is not only invariant to rotation and scale but also superior to the NCCH and the TRP method in clustering power. Furthermore, the performance improvement is expected by adding the distance information to the CSC.