基于轮廓与断面匹配的秦俑碎片拼接方法

Fragments Splicing Method for Terra-cotta Figures of Qin Dynasty Based on Contours and Fracture Surfaces Matching

针对兵马俑第3次发掘大量破碎俑片的虚拟复原需求,分析秦俑碎片拼接的特殊性,归纳陶制碎片的分类原则,提出一种结合碎片边缘轮廓和断裂面匹配的混合拼接方法。依据俑体碎片断裂面厚度,将其映射到空间曲线模板或空间曲面模板。基于积分不变量计算俑体碎片特征向量,采用一致性约束方法获取碎片初始匹配点对。利用筛选算法去除伪初始匹配点对,应用几何哈希算法寻找碎片最优匹配点对。其中,空间轮廓曲线匹配基于多边形弧串匹配法,空间曲面匹配基于多尺度积分不变量法。对破碎兵俑和陶马的拼接结果表明,该方法能正确得到碎片间的匹配关系,具有较好的鲁棒性。

To meet the virtual restoration requirement of large amounts of fragments in the third excavation of Terra-cotta Warriors and Horses, properties of the fragments are analyzed, and the classification principles of earthen tub fragments are induced. In view of the fragment classification and different thicknesses of the fracture surfaces, a fragments splicing method is proposed, which combines the spatial contour curves matching and the spatial fracture surfaces matching. All of the fragments are classified according to the thickness of sections, and different matching methods are employed to adapt to differem types of fragments. The multi-scale integral invariants are used as the feature representation methods for the contour curves and fracture surfaces, and the initial matching point pairs are obtained by the consistency constraint method. The filtering algorithm is used to remove the pseudo matching points, and the geometric hashing algorithm is used to find the optimal matching to get the local and global matching. This method is applied to the restoration of Terra-cotta Warriors and Horses, and the results show that it can get correct matching relationship between fragments and has good robustness.