Surface Reconstruction by Triangular Mesh of Models with Uneven Density and with Hole

.....................................................................................................................................i Acknowledgements .................................................................................................................. ii List of Figures ........................................................................................................................... v List of Tables .......................................................................................................................... vii Chapter 1: ................................................................................................................................. 1 1.1 Motivation ....................................................................................................................... 4 1.1.1 Example of 3D computer-aided modelling in artificial tooth .................................... 6 1.2 Objectives and scopes .................................................................................................... 9 1.3 Methodology ................................................................................................................... 9 Chapter 2: ............................................................................................................................... 11 2.1 Data acquisition Introduction ..................................................................................... 11 2.2 Active sensing equipment ............................................................................................ 14 2.2.1 Laser measuring methods ........................................................................................ 14 2.3 Passive sensing equipment ........................................................................................... 18 2.4 General processing ....................................................................................................... 21 2.4.1 Point cloud .............................................................................................................. 21 2.4.2 Mesh model ............................................................................................................. 22 2.4.3 Reconstruction mesh from point cloud ................................................................... 23 2.5 Existing theory .............................................................................................................. 24 2.5.1 Algorithm Based on Delaunay triangulation method .............................................. 24 2.5.2 Reconstruction method based on implicit surface ................................................... 27 2.5.3 Boundary extension method .................................................................................... 29 2.5.4 Based on learning method ....................................................................................... 31 2.6 Mainly existing problems of methods above .............................................................. 33 2.6.1 Theory based on Delaunay triangulation method .................................................... 33 2.6.2 Theory based on implicit surface ............................................................................ 33 2.6.3 Theory based on boundary extension algorithm...................................................... 34 2.6.4 Theory based on learning reconstruction method.................................................... 34 Chapter 3: ............................................................................................................................... 35 3.1 Overview ....................................................................................................................... 35 3.2 Import .txt file in Solidworks ...................................................................................... 35 iv 3.3 Data pre-processing ...................................................................................................... 36 3.3.1 Unified point cloud’s order of magnitude ............................................................... 36 3.3.2 Determine boundary value ...................................................................................... 37 3.3.3 Point cloud data simplification ................................................................................ 41 3.4 Seed triangle and candidate point preparation ......................................................... 45 3.5 Boundary extension with topological reconstruction ................................................ 48 3.5.1 Loop 1 for all points in PointXYZ() ......................................................................... 49 3.5.2 Loop 2 for all points and edges ............................................................................... 54 3.6 Algorithm conclusion ................................................................................................... 57 Chapter 4: ............................................................................................................................... 58 4.1 Algorithm Analysis ....................................................................................................... 58 4.2 Reduction comparison ................................................................................................. 62 4.2.1 Reduction cube working efficiency test at different length ..................................... 63 4.2.2 Reduction cube working efficiency test by mesh quality ........................................ 67 Chapter 5: ............................................................................................................................... 73 5.1 Conclusions ................................................................................................................... 73 5.2 Recommendations ........................................................................................................ 74 References ............................................................................................................................... 75 Appendix ................................................................................................................................. 81