基于形状骨架图匹配的文物碎片自动重组方法

为了有效解决文物碎片自动重组中由于断裂部位受损造成几何信息丢失，采用传统几何驱动方法容易失效的问题，本文提出一种基于形状骨架图匹配的文物碎片自动重组方法，将碎片匹配问题转化为碎片表面纹饰中非完整纹元的互补匹配问题.首先，通过提取文物碎片表面特征线得到碎片表面的纹饰信息；然后根据完整纹元的特征确定非完整纹元互补匹配的约束条件，采用视觉骨架剪枝的方法提取完全位于断裂部位的非完整纹元的形状骨架图，基于形状骨架图语法及匹配约束条件判定非完整纹元是否互补匹配；接着，将碎片上非完整纹元的顺序作为上层约束条件，采用基于带剪枝深度优先的搜索方法搜索匹配碎片；最后，以邻接碎片上非完整纹元间公共弦的端点作为邻接约束点，采用最小二乘法计算刚体变换参数得到碎片的初始位置，并采用迭代最近点方法将邻接碎片精确对齐.实验结果表明，该方法能够有效解决断裂部位存在缺损文物碎片的自动重组问题.

Reassembly of Fractured Fragments Based on Skeleton Graphs Matching

In order to effectively address the problem that traditional geometry-driven methods fail to reassemble the fragments with incompleteness in fracture surfaces or break-curves, an automatic reassembly method based on skeleton graph of shape matching is proposed, which transfers the matching of fragments into complementary matching of incomplete geometry texels. Firstly, the surface ornamentation information is obtained by extracting the feature lines of the fragments. Secondly, the constraints for matching texels are designed according to the features of complete texels, and a visual skeleton pruning method is utilized to generate the skeletons of the shapes of the incomplete texels and the grammar of skeleton graphs is introduced. Then, the sequence of the incomplete texels is used as the upper constraint and a depth-first searching method with pruning for adjacent fragments is presented. Finally, the endpoints of the common chords of the incomplete texels on the adjacent fragments are used as the initial matching points in order to calculate the initial position of the fragment. After that, the iterated closest point (ICP) method is employed to precisely align the adjacent fragments. Experimental results show that the proposed method can successfully solve the reassembly problem of the fragments with incompleteness in fractured surfaces and break-curves.