A control point theory for boundary representation and matching

There are several methods available for representing boundaries in two dimensions. The more widely known ones involve boundary modeling with run-length codes, chain codes and polygons, AR model coefficients, Fourier descriptors (FD´s) and B-spline control points (CP´s). In this paper, we present results showing the usefulness of CP´s in boundary representation. CP´s can yield large compression of the boundary data and they exercise local control over boundary shape. Because they can be normalized with respect to scale, translation and rotation, they are valuable in boundary matching applications. Finally, being the series coefficients of spline basis functions, CP´s are useful features for boundaries detected in noisy environments.