Multiresolution chain coding of contours

A multiresolution chain coding scheme for contours is developed based on 4-connected chain codes at progressively more refined grid sizes. By taking advantage of a specific set of possible paths a contour can travel, the algorithm presented generates a multiresolution representation of a contour, with the final refinement representing the original contour with the same accuracy as conventional 4-connected chain coding. The technique described requires only a small overhead in comparison to 4-connected chain coding, so has the advantage of providing a hierarchical representation of a contour at little cost. The generation of a multi-scale representation allows the algorithm to perform well in the presence of storage or transmission limitations, as only a fraction of the data is required to obtain a detailed representation of the entire contour