叶片截面线特征点的快速提取及其实验研究

针对叶片加工过程中的测量效率问题,从叶片截面线的曲率突变性出发提出一种提取截面线特征点的方法.根据截面线离散点积分曲线的单调性将截面线划分为曲率平滑区域与曲率突变区域,综合离散点曲率与区域性质选取基本特征点.构造B样条曲线逼近原始曲线,直到两曲线之间的Hausdorff距离满足预设阀值,完成特征点提取.计算及实验结果表明,特征点分布疏密程度与截面线曲率变化相关.在阀值为0.05mm的条件下,算法平均压缩率达到98%,平均计算时间为103 s.相比传统方法,该方法能快速收敛到设定误差,对提高叶片测量效率有一定指导意义.

Rapid Extraction of Feature Points and Experimental Research on Blade Section Curve

For the problem of improving the measuring efficiency in blade machining process， a new method was proposed for extracting feature points， which was based on the curvature mutation of blade section curve. According to the monotonicity of discrete points integral curve， section curve was classified into the curvature smooth region and curvature mutation region. The basis feature points were selected by the curvature of discrete points and the character of region. B-spline was structured to approximate the original curve. The extraction of feature points was completed when the Hausdorff distance between the constructed B-spline and original curve met preset error value. Calculations and experimental results showed that the density of feature points are related to curvature variation of section curve. When error is set as 0.05mm， the average compression rate can reach 98% and average computation time is 103 seconds. Comparing to the traditional method， it can convergence to preset error value quickly. The proposed method is potentially useful for improving measuring efficiency of blade.