Matching and recognition of planar shapes using medial axis properties

Using the geometrical properties of medial axis of closed planar shapes, we propose a shape representation called chain of circles (CoCs), and show its use for shape matching and recognition. CoCs is directly extracted from a resulting axial con guration of shapes along boundary curves without any intermediate description like graph obtained from segmenting shapes, and has the form of vector, each of which components is related with the parallelness and relative thickness of local shapes, the structure of whole shapes, and so on, respectively. The dynamic programming technique is used to match two shapes represented by CoCs and produces relative distance vector between shapes. The distance vector facilitates recognition by e cient indexing and retrieval of shapes in image database. Through experiments we show that the proposed method can be e ectively used not depending on shape class.