复杂几何对象高精度数字化重建理论与方法

杨必胜　张帆　方莉娜　臧玉府　王晏民　侯妙乐　赵仁亮

摘 要：该研究的目标：研究多源、异构数据特征感知与融合的技术与方法，针对文化遗产的数字化复原需求，研究多源数据融合的文化遗产高精度重构方法，建立文化遗产的多尺度高精度表达模型，为文化遗产数字化存档、虚拟修复、个性化展示等提供科学依据。为此，我们提出了一种基于空间曲率特征和形状特征的高精度点云自动配准方法。在曲率特征点的计算基础上利用点云聚类传播和脊线提取技术，提取出信息量丰富的三维脊线，融合形变能量模型和最小二乘匹配方法，全面地描述空间曲线的形状特征，同时利用曲线间的空间关系和最佳转换参数筛选策略，完成高精度点云自动配准。通同时提出了一种基于兴趣边缘优化的壁画影像与激光扫描数据非刚性配准和高精度纹理映射方法。利用激光扫描数据的强度信息生成强度影像，以壁画彩色影像的兴趣边缘和强度影像的梯度场作为配准基元，在影像刚性配准基础上，对每条兴趣边缘进行优化配准，然后以优化后边缘的特征点为控制，构造影像之间的非刚性变换模型，完成壁画影像与激光扫描数据的配准。针对缺失的几何部件，该课题主要研究基于拉普拉斯算子的石质文物点云模型骨架线提取方法、不同尺度空间曲线相似度的分析方法来进行文物虚拟修复，提高交互式文物虚拟修复的可靠性。通过对敦煌莫高窟159号洞窟佛像的激光扫描数据（共22.4G，点云精度1 mm）和纹理数据的多次自动配准实验表明该课题在文化遗产高精度数字重建的效果显著。

关键词：点云配准 三维重建 纹理映射 虚拟修复

Abstract：Digital heritage and archaeology have attracted a lot of attention of researchers in the world. Capturing digital representation of heritage objects can be used for the preservation， restoration， access， and scholarly study. The pipeline of 3D digitization includes 3D data capturing， 3D registration， geometric modeling and texture mapping. For capturing 3D data， we can use different methods to obtain the lidar data or imagery data from several views. The multi-views and multi-sources need to be registered and merged. Therefore， based on the curvature feature points， the three-dimensional crestlines with rich information are extracted by using the point cloud clustering method and ridge line extractiontechnology. The shapes of space curves are accurately described by merging deformation energy modeland least square matching method. In order to complete the high precision point cloud automatic registration， the spatial relationship between the space curves and the optimal selection strategy oftransformation parameters are explored. For realistic rendering， texture mapping is needed to map high resolution photos onto the geometric models. Texture reconstruction of 3D sculpture is explored by using non-rigid transformation. A method of cultural relic virtual restoration is proposed based on 3D fine model. Experiments using the laser scanning data and image data of the Buddha of DunhuangMogao grottoes 159 cave （22.4 G totally， the accuracy of point clouds with 1 mm）. Multiple automatic registration and texture mapping experiments show that our methods are able to reconstruct the cultural heritage with high precision.

Key Words：Point clouds registration；3D reconstruction；Virtual restoration；Texture mapping

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