基于形状指数的文物表面局部几何特征提取与匹配算法

Local Geometric Features Extraction and Matching Algorithm of Cultural Relic Surface Based on Shape Index

对具有整体形状相似而细节差异明显的文物模型进行基于全局的形状检索,由于精度限制很难得到满意的检索结果。为此,提出一种提取局部几何特征的检索算法,计算模型顶点的主曲率值,通过主曲率求出点所在局部曲面的形状指数,根据形状指数使用区域生长和扩张搜索方法获得模型的局部几何特征,再将获得的局部特征结合先验知识创建模板库,比较模板和待检测模型局部几何特征的相似度。以兵马俑甲胄碎片作为实验数据,应用该算法对甲胄碎片进行识别和分类,结果表明该算法是有效和可行的。

The global shape retrieval is used for relic model which has the characteristics of similar overall shape and obvious detail difference. Due to the limitation of accuracy, it is difficult to obtain satisfactory retrieval results. So this paper proposes a retrieval algorthm for local geometric feature extraction. The principal curvature of each model vertex is calculated, and the shape index of the local surface is obtained from the principal curvature. The local geometric features of the model are got by using region growing and expanding search method based on the shape index. The template library is constructed with the local geometric features and prior knowledge. The similarity of the template and the detected model is compared. The Terra-cotta Warrior pieces are used as experimental data and the proposed method is applied to identify and classify the pieces. Experimental results show that the method is effective and feasible.