适用于多值曲面修复的空洞边界提取方法及应用

摘要

For traditional extraction methods of hole boundary are affected by noise and single-valued surface, an automatic extraction method is proposed for the multi-valued surface repair to overcome the problem of overlapping projection. Firstly, the points ofk nearest neighbors calculated from the scattered point clouds are projected to the plane by the method of ALS. Secondly, the mesh is divided within the plane to extract the boundary grid and boundary linewith the application of minimum convex hull. Finally, the hole boundary and the object boundary are identified. In order to illustrate the validity of this method, it is applied to fill up the hole and surface reconstruction which is used to analyze and evaluate the accuracy using the quantitative evaluation index of the maximum distance and the average distance from the sample points to the built surface model. The results show that ALS and the minimum convex hull can keep features and avoid the problem of overlapping projection. The extracted hole boundaries are very precise to meet the needs of follow-up modeling%针对常用的空洞边界提取方法在噪声干扰和投影单值方面的缺点，提出一种能克服投影重叠问题而适用于多值曲面修复的空洞边界自动提取方法。首先求出散乱点云的k近邻域，利用推进式逐层求解法ALS将各近邻域点投影至平面；然后在平面内进行网格划分及提取边界网格，在此基础上应用最小凸包法提取边界线；最后，进行空洞边界与物体本身边界的识别。为了验证其有效性，将该方法应用于后续的空洞填充及曲面重构中，并选用采样点到所建曲面模型的最大距离和平均距离为定量评价指标进行精度分析及评价。试验结果表明，采用ALS以及最小凸包法能够保留特征和避免投影重叠，所提取的空洞边界精确，能够满足后续建模的需要。