Apparatus and fast method for convex-polygon bounding of closed contours

Abstract

An apparatus and computer-implemented polygon bounding method generate, in a first step, a binary array representation of a closed contour input object relative to a reference coordinate system. Subsequently, in a single pass through the binary array, a bounding polygon is generated as a sequence of parallel 'bands,' each representing a pair of opposing sides of the polygon. The polygon bands are oriented at successive generally uniform rotations of the reference coordinate system and are positioned to define the bounds of the closed contour for each rotation angle. The spacing and positioning of the bands can thus be used to define polygon size and position at each angle. In this way, comparisons between a plurality of polygons can be made systematically using defined geometrical criteria.