基于支持向量机的点云数据修补

【作者】 吴岩冰；

【导师】 马胜钢； 陈中中；

【作者基本信息】 郑州大学 ， 机械制造及其自动化， 2009， 硕士

【摘要】 逆向工程是通过产品扫描数据来重建产品数据模型,进而进行产品开发和制造的技术。其主要包含数据采集和数据处理两方面的内容。数据处理中的数据修复可为后续的曲面重构及产品模型建立降低难度和缩短所耗时间,因此对数据修复进行研究具有较高的实用价值。本文在三维结构光测量的技术背景之下,针对缺损点云数据的修复处理进行了研究。缺损点云中通常只包含点的三坐标信息,而不具备各点间的拓扑关系。为使边界提取算法能实现自动搜索缺损区域的边界轮廓,引入角度阈值作为修补区域边界点的判定依据;同时提出将空间点投影到最小二乘平面,再利用平面上投影线段间夹角和阈值的比较来判定边界点的方法。随后依据边界点间的距离关系,将求出的边界点连接成边界线,再确定其方向和内外关系,最终确定出所需修复的缺损区域。本研究提出利用支持向量机的非线性回归算法,来对点云数据中缺损区域进行修复,并通过实例验证该方法的可行性。论文重点分析了曲面修补效果与缺损区域边界处数据点的空间落差的对应关系,得出修补精度范围和适用场合,同时讨论了该方法在曲面修补过程中的局限性。更多还原

【Abstract】 Reverse engineering is a advanced technology in engineering, it can exploit and produce products through rebuilding scan data model. It has two contents which are data acquisition and data processing respectively. Data repair can shorten operational time for succeeding reconstruction and model building. Therefore, research about data repair in RE in this paper has a high practical value. In the technical background of collecting data within three-dimensional structured light, the defect data repairment is researched in this paper.Defect point cloud includes merely the coordinate value of points, it has no topological relations in points. In order to automatically search out boundary contour which needs repaired, threshold angle is introduced as the standard of judging boundary points. A new method is proposed to project space points to least-squares plane, and then uses the comparison of angles between projection line sections and threshold angle to judge the boundary points. Based on the distance between boundary points, boundary line is generated. Finally, the direction of boundary line, the internal boundary line and region which needs repaired can be found out.The paper proposes a method to repair the defect region of scattered point cloud. The method builds mathematical model with non-linear regression algorithm of support vector machine. The feasibility of method is verified through repair examples. The relationship between the effect of surface patch and the space fall of boundary points is analyzed. At the same time, accurate repairing scope, situation of application as well as the limitations of this method are be discussed.更多还原