A differential code for shape representation in image database applications

A new method termed the vertex representation is presented for approximating the shapes of objects of arbitrary dimensionality d (e.g., 2D, 3D, etc.) with orthogonal (d-1)-dimensional faces using a variable number of vertices. The vertex representation can be viewed as a generalization of boundary codes (i.e., chain codes) to higher dimensions. Techniques are described for using the vertex representation to efficiently perform many operations commonly performed on rasters. The utility of these techniques in image database applications is discussed