Self-affine mapping system for object contour extraction

A self-affine mapping system which has conventionally been used to produce a fractal image is used to fit the rough line to the contour. The self-affine map's parameters are detected by analyzing blockwise self-similarity of a grayscale image using a simplified algorithm in fractal encoding. It is also shown that even large gaps between the hand-drawn line and the contour can be fitted well by the recursive procedure of the proposed algorithm, in which the block size is progressively decreased. The proposed method produces not only smooth curves but also sharp corners.