Research On Geometric Modeling And Cutting Relative Technologies In Virtual Surgery

Virtual surgery is a new application technique, which appears due to virtual reality and modern medicine's combination. By using various medical image data, virtual surgery system can present a simulating surgery scene for surgeons. Surgeons can make surgery plan, predict surgery result, train students by making use of image segmentation, geometrical modeling, realistic rendering, haptic feedback, virtual cutting, collision detection.In this thesis, we study several key techniques in virtual surgery. The main contents of this paper are listed as follows:1. Geometrical modeling techniques. This thesis studies triangle mesh model reconstruction and simplification algorithms, provides a constrained Delaunay tetrahedralization method and realizes tetrahedron mesh model reconstruction. To meet the requirements of finite element analysis on the mesh quality, an effective mesh optimization method is presented to eliminate silver tetrahedron, improve the quality of tetrahedral mesh model.2. Virtual cutting techniques. For triangle mesh model, two cutting methods are presented. One is arbitrary plane cutting, and the other is closed region cutting method based on projection. For tetrahedron mesh model, introducing element elimination method and element subdivision method, and analyzing several cutting methods' advantage and disadvantage. By using an improved tetrahedron subdivision method, realizing tetrahedron mesh model cutting.3. Collision detection techniques. This thesis analyzes several bounding volume methods' advantage and disadvantage. Based on the characters of collision detection in surgery simulation (rigid body and rigid body collision, soft body and rigid body collision), and considering efficiency and accuracy, we prove fixed direction hull (FDH) bounding volume is a good choice. In the thesis, updating methods on FDH bounding volume after object rotation and deformation are provided.4. Implementation of a virtual surgery system. An extendable virtual surgery system is designed and implemented, which achieves good experiment results, and lays the foundation for future study work.