基于逆向工程的人工膝关节测量点云光顺建模研究

Research on Point Cloud Smoothing in Knee Joint Prosthesis Modeling Based on Reverse Engineering

临床中实施人工膝关节假体置换手术时,大多使用国外进口的能很好地反映人体膝关节生物形态的标准型号。本研究基于逆向工程技术对国外同类产品实施反求,采用新的定位方法对表面实施数据采集,并提出三点夹角点云去噪算法和基于最小二乘法拟合平面的点云补点算法对测量点云进行光顺,然后生成准确度和光顺度较好的人工膝关节假体曲面,最后生成人工膝关节假体模型,这为人工膝关节的国产化奠定了基础。此种新算法主要适用于人工膝关节假体这一类型曲面和形状较规则及曲率变化平缓的自由曲面的测量点云光顺建模。

At present, foreign standard knee joint prosthesis is mostly used in clinical practice; it can well represent the biological characteristic of knee joint on human being. So this paper adopts the reverse engineering technology in that connexion, presents novel positioning method of acquiring the point data on the surface of knee joint prosthesis, puts for- ward the algorithm of three-point angle method for removing the noise error and correcting the noise error based on the least .squares plane to smooth point cloud. And then, the surface of knee joint prosthesis with better accuracy and smoothness can be generated. Finally, the knee joint prosthesis model can be generated. Thus, a basis is provided for the localization of knee joint prosthesis. This new algorithm is mainly used for the surface modeling based on point cloud smoothing, including the surface of knee joint prosthesis, the surface of regular shape, and the surface with gentle change in curvature.