Rotation independent hierarchical representation for Open and Closed Curves

Abstract

The algorithm used for the segmentation of an image, and scheme used for the representation of the segmentation result are mostly selected based on the final image analysis or interpretation objective. The boundary based image segmentation and representation system developed by Nabors segments and stores the result as a graph-tree hierarchical structure that is capable of supporting diverse applications. This paper shows that Nabors' hierarchical representation of curves is not invariant to rotation, and proposes an enhanced representation which retains its structure and remains invariant under rotation. The curve matching algorithm which matches two curves based on their hierarchical representation makes it easy to determine if a curve is a section of a larger curve. The potential of the representation is illustrated by developing image registration and image stitching methods based on the new representation.