Shape decomposition based on erosion model

Abstract

W e present a shape decomposition method based o n e ros ion model t o extract convex parts f r o m a planar closed shape. Our approach i s based o n the curvature analysis of shape contours assuming that divisions of a shape generally occurs at concavities o n the contour, as if the sea gained o n the land along the coast. W e call this model as e ros ion model. The outline of our algorithm i s as follows. As a beginning, the vectorized shape contour i s extracted f r o m a silhouette image. Next , a n erosional vector which represents a force of erosion at each concavity i s computed, and then, a boundary which splits the shape i s decided. These processes are recursively performed until no division is available. Finally, some parts are merged if necessa y. T h e advantage of our approach i s that the meaningful convex part can be obtained ef ic ient ly and the decomposit ion results are theoretically invariant to translat ion, rotation and scaling.