A simple proof of Rosenfeld's characterization of digital straight line segments

Abstract

A digital straight line segment is defined as the grid-intersect quantization of a straight line segment in the plane. Let S be a set of pixels on a square grid. Rosenfeld [8] showed that S is a digital straight line segment if and only if it is a Digital arc having the chord property. Then Kim and Rosenfeld [3,6] showed that S has the chord properly if and if for every p, q ϵ S there is a digital straight line segment C ⊂ S such that p and q are the extremities of C. We give a simple proof of these two results based on the Transversal Theorem of Santaló. We show how the underlying methodology can be generalized to the case of (infinite) digital straight lines and to the quantization of hyperplanes in an n-dimensional space for n ≥ 3.