【作者】 尹丹；

【导师】 耿国华；

【作者基本信息】 西北大学 ， 计算机应用与技术， 2008， 硕士

【摘要】 随着世界文化遗址保护工作的发展,利用计算机辅助遗址保护的相关技术成为近年来计算机可视化技术研究的热点,其中数字化是保护和推广文化遗址的主要方法之一。由于文化遗址的多样性和复杂性,遗址数字化的准确性依然难以保证。本文主要研究利用激光扫描仪获取的深度数据对古建筑进行数字化过程中的三维数据配准技术。以小雁塔的三维虚拟数字化为研究对象,用激光扫描仪获取了小雁塔场景的点云数据,研究主要集中在点云数据预处理、多次扫描的深度图像配准、点云数据建模等方面,主要研究内容如下:1)点云数据预处理。研究了三维点云数据的组织方式,对所获得的大场景点云数据采用了随机采样和曲率采样混合的方法进行了简化,并利用中值滤波剔除奇异点,在保证原始数据可靠性的基础上有效的降低了数据量。2)深度图像分割。采用了Stamos提出的分割算法,用最小二乘法对点云数据进行局部平面拟合,利用共面性和同向性合并相似的平面,得到了小雁塔的深度图像分割结果,在此基础上采用了基于平面特征的方法进行了初步配准。3)深度图像配准。研究和分析了经典ICP算法,针对古建筑的结构特征对该算法进行了改进,引入了平面特征的概念,并采用基于平方距离函数的改进ICP算法对初配准的结果迭代求精,实现了小雁塔深度图像的精确配准。4)点云数据建模。通过对几种常见的三维重建算法的研究与比较,对简化并且配准的点云数据采用Delaunay三角剖分的方法进行了网格化,得到了比较逼真的三维模型。更多还原

【Abstract】 As the development of protection of world cultural sites, the technology of computer-assisted sites protection has been the hotspot of the Computer Visualization Technology study. The digital is one of the major methods of preserving and promoting the culture sites. Due to the variety and complexity of the sites, it is still difficult to guarantee the accuracy in the digital of sites.Paper is mainly on the study of 3D virtual digital SMALL WILD GOOSE PAGODA, acquiring the point cloud data from 3D laser scanner. Research focused on point cloud data preprocessing, multi-view registration, point cloud data modeling aspects. Main contents are as follows:1) The pretreatment of point cloud data. Lots of researches of the organization of 3D point cloud data have been done. We have simplified the scenes point cloud data by the mixture method of random sampling and curvature sampling, and eliminated the singularities by using the median filtering, which reduced the volume of data effectively on the basis of assurance for the reliability of the original data.2) The segmentation of range image. The segmentation method brought forward by Stamos has been chosen by fitting the partial plane of point by the method of the least squares fitting and combining the similitude plane based on the co-normality and co-planarity. We have achieved the segmentation results of the range images and registered them on the basis of planar feature primarily.3) The registration of range image. We have studied and analyzed the classical ICP arithmetic, and improved it aiming at the structure features of the ancient architecture by relating the definition of planar feature and iterating the result of first-step-registration by the improved ICP arithmetic based on the square distance function, which implement the accurate registration of the range images of the SMALL WILD GOOSE PAGODA. 4) The reconstruction of point cloud data. The paper also has generated meshes by using method of Delaunay triangulation from the point cloud data simplified and registered and achieved the realistic 3D models, through the comparisons and researches of several common methods of 3D reconstruction.更多还原