基于数字化光顺性指标的NURBS曲线自适应光顺

摘要

目前曲线曲面光顺算法大都基于手工操作,自动化程度低,难以对曲线曲面进行自适应光顺.针对此问题,文中给出一种数字化光顺性指标SValue的定义,基于此定义,提出了一个对NURBS曲线自适应的光顺算法.该算法通过对曲线小波分解,得到其尺度部分和细节部分.然后压缩细节部分得到光顺后的曲线,通过计算SValue来评定曲线的光顺效果.最后递归光顺曲线,直到满足光顺要求.与其它光顺方法相比,该方法不仅直观,而且光顺效果更佳,算法的自动性和自适应性更好.%Currently most of methods about the NURBS Curve fairing are normally based on manual methods. It is a challenge to fair NURBS curve automatically and adaptively. In this paper, a digital definition of fairness is given, which is called Svalue. Based on the digital index Svalue, an adaptive NURBS curve fairing algorithm is presented. Firstly, the curve is decomposed into a detail part and a scale part. Secondly, the detail part are compressed by setting a threshold automatically. Finally, the new control points are obtained by the wavelet reconstruction. The curve fairness can be valued by the digital index Svalue. By giving Svalue a target value, the fairing algorithm can fair curve automatically. Several examples are given to illustrate the feasibility and effectiveness of this approach. Compared to other fairing methods, the algorithm can fair the curves better and more efficiently.