Hierarchical representation of 2-D shapes using convex polygons: a contour-based approach

A concavity tree is a data structure for hierarchically representing the shape of two-dimensional silhouettes using convex polygons. In this paper, we present a new algorithm for concavity tree extraction. The algorithm is fast, works directly on the pixel grid of the shape, and uses exact convex hull computations. We compare our method to the morphological approach to concavity tree extraction and we report better computational performance and smaller reconstruction errors.