等值线光滑算法及其适用性分析

Contour Smoothing Algorithm and Its Applicability Analysis

对比分析了五点法、张力样条函数法和Bezier函数法在等值线光滑中的适用性,针对Bezier函数法中曲线在等值点位置缺失的问题,引入了以等值点和切线点共同作为控制点的方法进行改进。结果表明,在一定等值点密度下,五点法仅适用于数量指标变化平缓、等值线分布较稀疏的情况;数量指标变化剧烈时,宜采用张力样条函数法或改进后的Bezier函数法。改进后的Bezier函数法能够平滑经过所有等值点位置,且不会出现多余的拐点,光滑效果较传统方法有明显提升。

In this paper,we analyzed the applicability of common contour smoothing algorithms such as the five-point method,the tension spline function method and the Bezier function method.Since the Bezier function method missed the contour points,we introduced a method that took both contour points and tangent points as control points to improve the Bezier function method.The results show that the five-point method works effectively only when indicator changes slowly and the contour is sparsely.If the indicator changes rapidly,the tension spline function method and the improved Bezier function method work better.The improved Bezier function method is able to link equivalence points smoothly without producing extra inflection points,and the smoothing effect is significantly improved compared with the conventional method.