广义B 样条曲线具备了B 样条曲线的各种优良性质, 又因为其独具的核函数为形状设计带来更加丰富的可能性, 文中提出了广义B 样条曲线的节点去除与光顺算法. 首先给出了构造广义B 样条对偶基的新方法, 其时间计算复杂度得到了很好的控制; 其次摘除需去除的节点, 再利用对偶基的最佳逼近性质, 采用广义B 样条的对偶基求得新的广义B 样条曲线的控制顶点; 在广义B 样条曲线光顺中引入跳跃值的概念, 如果某个节点附近的跳跃值较大,则去除相应的节点, 从而实现在此节点处的光顺. 最后通过大量的数值实例, 展示了算法的有效性.
Generalized B-splines are not only compatible with classical B-splines but also provide plentiful shapes for geometric modeling systems because of their flexible core functions. The paper focuses on knots removal and smooth method of generalized B-splines. Firstly, the dual bases of generalized B-splines are constructed, and the complexity can be reduced a lot. Secondly, jump value is introduced, if jump values of some knots are too big, the corresponding knots are removed. At last, by the aid of best approximation prop-erty of the generalized B-splines’ dual bases, control points of new approximating generalized B-splines are obtained. Thus, knots removal and smooth of curves are realized. Numerical examples are given to illustrate the effectiveness of the method.