Chord-to-point distance accumulation and planar curvature: a new approach to discrete curvature

In this paper we present a method of calculating a property - which can be regarded as a discrete curvature - of planar digital boundaries. Chord-to-point distance accumulation is computed by accumulating the distance from a point in the boundary to a chord specified by moving end points. According to the shape of the boundary, positive or negative distances are obtained. The values are accumulated as the chord is moved. The distance accumulation is robust with respect to change of chord length compared to planar curvature. The scale space image of the distance accumulation showed that the zero crossings of distance accumulation are quite stable. Experimental results with simulated and real images showed its robustness. Analysis of its relation to planar curvature matched very well with experimental results. (C) 2001 Elsevier Science B.V. All rights reserved.