| The ancient cultural relics reflect the political, economic and cultural in acountry and nation in a certain period. However, Many culture relics and sites havebeen on the verge of great danger because of the natural environment and humanactivities. By means of the new technological,the work that keep the originalcultural relics, such as protection of cultural heritage and v irtual restoration, hasbecome a global hot research probles. The development of data acquisitionequipment and computer technology brings a kind of brand-new situation for thework of protecting cultural relics. A new progress has began in the protection ofcultural relics.The work of Cultural relics protection not only need to puts muchemphasis on the its application in information retention and digitaldemonstration,but also need to provide scientific data for restoration.Some cultural relics structure is very complex, the surface appears irregularshape，The traditional measuring method cannot get comprehensive and detailedthree dimensions (3D) geometry information of cultural relics, and it suffers manytroubles such as low automation, low speed and low precision.3D laser scanning asa new, high-level technology of mapping and information, has undergone drasticdevelopment during recent years, and provides a new approach in the conservationof cultural relics.3D laser scanning using3D laser radar to acquire3D pointcoordinates and grayscale information of the target space.3D digital model of highfidelity can be constructed using related data processing software. In therestoration of cultural relics, it often needs to estimate the amount of restorativematerials. Calculate the Volume of irregular surface cultural relic based on3Dmodel and defect areas of cultural relics and Surface area of the3D model, forproviding important data support for the work of restoration of the cultural relics.Extracting contour line of model of cultural relics for Cultural relics researchersanalysis the cultural relics outline feature. The main results of the thesis are asfollows:1. Extract boundary using boundary property of triangular mesh. Distinguishholes boundary and model exterior boundary by means of direction of the normalfor a triangle. The areas of three-dimensional holes polygon are calculated tostatistics defect areas of cultural relics.2. Calculate and surface area and volume of3D mesh model using theimproved sign volume of tetrahedron algorithm.3. Extracte contour line of3D mesh model using optimized slicing algorithm.Facet grouping is performed by sorting the coordinates of vertices in ascendingorder of the z direction. Compare the triangle with the cutting plane, compute the intersection vertex and store the intersection line. In the end, sort and close theintersection lines.4. Work out a3D visualization calculation software, which use the OpenGLtechnology for realization the visualization of scientific calculation, calculate thedistance between any two points of the model, inquire coordinates of the vertex inthe model and select part area of the model using the mouse and calculate its area.It can indirectly and non-destructive obtain accurate3D geometryinformation of cultural relics based on3D model, such as hole boundary, volume,area and contour line of3D mesh model. Select part area of the model using themouse and calculating its area, calculate the distance between any two points of themodel and inquires the arbitrary point coordinate information based on OpenGLtechnology,These important geometry information data, it provide scientific datafor restoration of the cultural relics. |
