基于几何特征的兵马俑断裂面匹配方法

针对兵马俑碎块的三维数据模型中噪声含量大、断裂面存在缺损等问题，提出一种基于断裂面上几何特征的碎块精确匹配方法.首先从兵马俑碎块的外表面中分割并识别出断裂面；然后提取断裂面上凸凹不平的特征区域，并根据其相似性实现碎块的粗匹配；最后计算断裂面的曲率、法线以及点云密度等几何特征，并采用基于该几何特征的改进迭代最近点（iterative closest point，ICP）算法实现碎块的细匹配.实验采用大量兵马俑碎块验证该匹配方法，结果表明该匹配方法可以实现兵马俑碎块的匹配，特别是提出的细匹配算法，与ICP算法和MICP算法相比，其匹配精度分别提高了约40%和10%，耗时分别降低了约50%和25%；该基于几何特征的断裂面匹配方法是一种有效的兵马俑碎块匹配方法. 

Fracture Surface Matching Method of Terracotta Based on Geometric Features

In order to solve the problems of large noise and defective fracture surface in the 3D data model of Terracotta blocks, a fracture surface matching method based on geometric features of Terracotta was proposed. Firstly, the fracture surfaces were segmented and recognized from the outer surface of Terracotta blocks; Secondly, the concave and convex feature regions of the fracture surface were extracted, and the coarse matching of blocks was completed according to the similarity of feature regions; Lastly, the geometry features including curvature, surface normals and point cloud density were calculated, and the fine matching of blocks was completed using the improved iterative closest point (ICP) based on the geometry features, thus the Terracotta blocks were matching accurately. A great number of Terracotta blocks were used to validate the proposed matching method. The results show that the proposed matching method can complete the Terracotta blocks matching. Especially the proposed fine matching algorithm, compared with ICP and MICP, the matching accuracy can increase by about 40% and 10% respectively, and the time consuming can decrease by 50% and 25% respectively. So the matching method based on geometric features is an effective Terracotta blocks matching method.