Contour simplification using non-linear diffusion

The non-linear diffusion of the method of P. Perona and J. Malik (see IEEE Trans. Pattern Anal. and Machine Intelligence, vol.PAMI-12, no.7, p.629-39, 1990; Proc. IEEE Comput. Soc. Workshop on Comput. Vision, p.16-22, 1987) is applied to a contour. Unlike most contour diffusion techniques, the contour is described by the angle variation, and the non-linear diffusion procedure is applied to the contour turning angle. The Perona and Malik model determines how strongly diffusion acts on the original function, and depends on a factor K, estimated automatically. In areas with spatial concentration of strong changes of angle, this factor is also adjusted to reduce the contour small perturbations and noise effects.