Research On Mesh Algorithms Of Surfaces Reconstruction Technology

This thesis is focused on the mesh methods of surfaces reconstruction from 3D volumetric datasets. The main topics include surfaces reconstruction from large volumetric datasets; mesh simplification; mesh fairing; virtual memory management technology applied in the data structure of mesh. This presentation is divided into six chapters.In the chapter 1, a survey is given about surfaces reconstruction technology in visualization in scientific computing. We introduce the sampling and classification of 3D volumetric datasets; and review the classification of surfaces reconstruction algorithms and mesh simplification algorithms.In chapter 2, we discuss the surfaces reconstruction technology from large volumetric datasets. Traditional surfaces reconstruction methods usually extract the iso-surface from 3D volumetric datasets, then smooth and simplified mesh. For large volumetric datasets, this kind of surfaces reconstruction methods must have enough memory space. Otherwise these methods can't work well. In this chapter, a layered surfaces reconstruction algorithm is proposed. Approximate mesh can be reconstructed and simplified layer by layer in smaller memory space. In the section of application examples, we reconstruct the mesh of brain modal, cerebellum modal, axis modal from the Visible Human Datasets. The results show that large surfaces reconstruction is viable in a personal computer using ours algorithm. Furthermore, the idea can be used in the transmission and simplification of large mesh.In chapter 3, we propose a mesh simplification algorithm based on vertex's curvature, which use edge collapse method to reduce the density of low-curvature region of meshes and use butterfly-mask to generate the new vertex. In the section of application examples, we simplify the cow modal and deer head modal. The results show that the curvature is useful to enhance the shape description, the shape of model mesh can be preserved well after our simplification process.Chapter 4 shows the virtual memory management technology applied in mesh data structure. With the improvement of 3D sampling devices, the volumetric datasets are becoming huge. The modal mesh reconstructed from the volumetric datasets is too huge to be loaded into the storage space. Although the WINDOWS operation system supply its virtual memory...