3维碎片拼合的算法研究

Algorithm for Three-Dimensional Fragments Reassembly

为实现艺术珍品保护或古器物修复中3维碎片的比对和拼接,提出了一种空间任意形状的3维碎片拼合算法。该算法首先对由实物测量数据建立的三角网格模型进行预处理,即去除模型中所存在的一些缺陷,以提取模型边界轮廓曲线;然后对碎片的边界轮廓离散点进行五次B样条插值,同时计算轮廓曲线上各个点的曲率、挠率和法矢,并据此分析3维碎片轮廓曲线的几何特性;接着根据轮廓曲线上各个点的总曲率来检测轮廓的特征点,并对轮廓进行分段;最后根据曲率、挠率的变化对不同轮廓上的特征段进行相似性度量,并运用法矢对相似性程度较高的轮廓段进行可匹配性验证,同时计算出可匹配轮廓段的坐标转换关系,以实现碎片的拼合。实例表明,该算法是高效、稳定的。

Fragments comparison and reassembly are necessary in art conservation or artifacts restoration. An approach to the problem of object reconstruction from broken fragments of arbitrm＇y 3D objects is proposed in this paper. The triangle mesh model derived from the range data of fragment is preprocessed to remove some unwanted limitations, and then the fragment contour is extracted. The discrete points on the boundary curve are interpolated by quintic B-spline. With the spline curve, the curvature and torsion of every point are calculated and the geometric property is also analyzed. Feature points are detected based on the total curvature of every point, and the contour is segmented accordingly. The similarity between feature segments belonging to different contours is measured according to the variations of curvature and torsion, meanwhile the normal vector is utilized to verify the matchable probability of similar space curves. Thus, the Euclidean transformation of matching contours is computed to achieve the fragment reassembly. Experimental results demonstrate the approach is robust and efficient.