Discrete, nonlinear curvature-dependent contour evolution

There has been much recent interest in curvature-dependent contour evolution processes, particularly when the resultant family of contours satisfies the heat (diffusion) equation. Computer simulations of these processes have used high-precision computation to closely approximate the solutions to the equation. This paper describes a class of low-precision contour evolution processes, based on a digital approximation to the curvature of the contour derived from its chain cede, that can be applied to contours in low-resolution digital images. We have found that these methods perform quite similarly to the PDE-based methods at much lower computational cost. Our methods are also not limited to using linear functions of the contour's curvature; we give several examples of digital contour evolution processes that depend nonlinearly on curvature, and discuss their possible uses. (C) 1998 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.