An algorithm of polygonal approximation constrained by the offset direction

In view of the existing polygonal approximation algorithm of digital curves can´t effectively solve the problem of polygonal approximation constrained by the offset direction, this paper proposes an algorithm of polygonal approximation constrained by the offset direction. First, the offset polygon of the original digital curve is calculated under the control of offset direction and distance. Second, the summation of the squared Euclidean distances between the vertices on the offset polygon and its corresponding segment in the approximated polygon is selected as the fitness function. Finally, under the control of the offset distance and fitness function, this paper implements a PSO-based polygonal approximation algorithm to approximate the offset polygon. Experiments show that the proposed method can not only satisfy the polygonal approximation with directional requirements, but also can greatly improve the operating efficiency.