Pruning discrete and semicontinuous skeletons

Abstract

Abstract. In this paper pruning techniques axe illustrated, which allow us to suitably simplify the (discrete and semicontinuous) skeleton, by either deleting or shortening peripheral skeleton branches. To avoid excessive shortening, which might reduce the representative power of the skeleton, the relevance of the figure regions mapped in the skeleton branches is used to decide on pruning. Different definitions of relevance are introduced and features allowing the quantitative evaluation of the relevance are suggested.

Medial Representations

“…We use elongation as the significance measure (Sanniti di Baja, 1994;Attali et al, 1995). We do not perform pruning if the branch corresponds to a region decreasing in width (i.e., if I(x) decreases along the branch).…”

Scale Filtered Euclidean Medial Axis

“…The simplest strategy to filter the medial axis is to keep only points which are centers of maximal balls of at least a given diameter. Different criteria can be used to locally threshold and discard spurious medial axis points or branches: see [1,12], for methods based on the angle formed by the vectors to the closest points on the shape boundary, or the circumradius of these closest points [8,15].…”

Computing a family of skeletons of volumetric models for shape description

“…Note in particular that the spurious surface branches do not provide meaningful information about the original object, and the chair legs can be represented in a simpler and more descriptive manner by curves instead of surfaces. Although numerous pruning methods exist for 2D skeletons [3,26], for skeletons of 3D point-set and polygonal models [21,2,1,11,12,29,27], or for removing only curve branches from skeletons of volumetric models [19,28], pruning both redundant curve and surface features from skeletons resulted from thinning remains an open problem.…”