Ernesto Bribiesca, Ph.D.
Universidad Nacional Autonoma de Mexico (UNAM)
Instituto de Investigaciones en Matematicas Aplicadas y en Sistemas (IIMAS)
Department of Computer Science
Phone: (5255) 5622-3617
FAX: (5255) 5622-3620
Each curve carries within it its own shape number
Using the Vertex Chain Code (VCC) it is possible to represent any 2D shape composed of triangular, rectangular (pixels), or hexagonal cells by means of only one chain. This notation is invariant under translation and rotation, and optionally may be invariant under starting point and mirroring transformation. The chain elements represent real values not symbols such other chain codes, are part of the shape, indicate the number of cell vertices of the contour nodes, may be operated for extracting interesting shape properties.
Chain-code techniques are widely used because they preserve information and allow considerable data reduction, chain codes are the standard input format for numerous shape analysis algorithms. Using the orthogonal direction change chain code it is possible to represent three-dimensional (3D) curves.