NEIGHBORING DIRECTION RUNLENGTH CODING - AN EFFICIENT CONTOUR CODING SCHEME

An improved exact coding scheme is proposed for two-tone digital contour. It is assumed that the contour is one pel thick and perfectly 8-connected. The basic idea in the scheme is to segment the contour at the positions where 90 degree bends occur. Each segment is considered as a unit for coding. For coding convenience, the subsegments belonging to the segment and runs in each subsegment are identified. The codeword consists of subwords representing the starting direction of the segment, subsegment identification, number of runs in the subsegments and number of pels in the runs. The scheme has been tested on several contours and the experimental results are presented and compared with the best known scheme. © 1990 IEEE