From 3D discrete surface skeletons to curve skeletons

An algorithm to compute the curve skeleton of a 3D object starting from its surface skeleton is presented. The voxels of the surface skeleton are suitably classified to compute the geodesic distance transform of the surface skeleton and to identify anchor points. Voxels are examined in increasing distance order and are removed, provided that they are not anchor points and are not necessary to preserve topology. The resulting curve skeleton is topologically equivalent to the surface skeleton and reflects its geometry.