Processing of line drawings in a hierarchical environment

A method for parallel processing of chain-codable contours is described. The proposed hierarchical environment, called the chain pyramid, is similar to a regular nonoverlapping image pyramid structure. The chain pyramid makes possible the fast computation of contours. The artifacts of contour processing on pyramids are eliminated by a probabilistic allocation algorithm. Processing modules are developed for smoothing of curves, gap bridging in fragmented data, and treatment of branch points. Raw edge data are preprocessed before being input into the chain pyramid. Typical results are presented and briefly characterized