基于激光点云数据的客家土楼三维建模

Three-dimensional Modeling of Hakka Earth Buildings based on the Laser Scanned Point Cloud Data

传统测量方法难以获得完整准确的几何信息,且在测量过程中对文化遗产的频繁接触也存在造成文化遗产损害的隐患。利用地面激光扫描技术开展了客家土楼真实感、精细化三维建模的应用研究。首先,在现场点云数据采集的基础上提出了基于点云数据的客家土楼三维高精度重建的具体过程;其次,对点云数据处理和三维实体重建两个核心步骤,重点对点云数据的配准拼接、去噪简化和分站处理、构件轮廓线提取、三维几何建模和纹理贴图等步骤进行了详细论述。另外,对建模过程中纹理优化处理这一难点进行分析探讨,给出具体解决途径。应用结果表明:三维激光扫描技术适用于具有高复杂度几何特征的客家土楼精确化、真实感建模,为客家土楼建筑文化遗产未来的开发与保护过程的损害情况监测、恢复重建和虚拟展示等提供了高精度的数据基础。目前,技术方法已应用于世界遗产地—福建客家土楼的数字化旅游信息服务中,成效明显。

Inscribed by UNESCO as world cultural heritage site,Fujian Hakka earth building is a wonderful work of ancient Chinese architecture with high architectural,cultural and tourism value.It is of critical importance with highly precise,realistic three-dimensional(3D)models of cultural heritage to fulfill the goals for their protection,preservation,communication and inheritance,and to promote virtual culture tourism.Hakka earth buildings are characterized as large size,with complex geometry and irregular shape,rich detail features,as well as fragile,vulnerable to manmade and natural damages.It is difficult to obtain complete and accurate geometric information by traditional survey and measurement methods.And it may induce harm to the cultural heritage with frequent contact in the measurement process.Terrestrial laser scanning and other technologies were used to create realistic,fine 3D models of Hakka earth building.Firstly,this study proposed a complete procedure for 3Dhigh-precision reconstruction of Hakka earth buildings based on point cloud;Secondly,some core steps in point cloud data processing and three-dimensional reconstruction,in particular point cloud data registration,simplification and de-noising,components contour extraction,three-dimensional geometric modeling and texture mapping are discussed in detail.In addition,we discussed the difficulties and specific solutions to texture optimization in the process of modeling analysis.Application results show that 3Dlaser scanning technology is well suited for precise,realistic modeling of Hakka earth buildings with high complexity geometric features,as provides high-precision data base for future development and protection,building damage monitoring,restoration and virtual display,etc.At present,the technical approach has been applied to the Fujian Hakka earth building digital tourist information services with excellent results.