| The techenolgy of visualization of medical imagings is related to the research fields of digital image processing, computer graphics, computer vision and medcine etc. This dissertation studies the techniques of geometry reconstruction including slice-imagings interpolation in 3D space, extraction of reconstrction target contours, surface reconstruction from planar contours, transformation between reconstrucion model and 3D solid model and collision detection of models. A prototype system of virtual fracture orthepedic surgery planning and simulated trainning is developed.The reconstruction is implemented from isotropic volume data. Slice-imagings interpolation can creat new slices. This dissertation presents a gray-level matching interpolation method based on object gray-level distribution probability knowlege, through which we can get more clear scene at the boundary between different matters than that in traditional interpolation methods. With respect to non-similar shapes or no superposition of corresponded contours on adjacent slices and concave contours, this dissertation introduces a method based on variant shape-based interpolation.The reconstruct region should be extracted befor 3-D reconstruction. For reconstruction from contours, this dissertation uses Active Contour Model(Snake Model) to check the boundary contours. The algorithm can generate single, continuous and close contours quickly. For reconstruction from voxel, this dissertation presents an algorithm to trace the boundary contours from segmented regions based on Active Contour Model.The algorithm can trace the contours of inter and outer connected multi-regions correctly and accurately, and can prevent tracing from jumping out to the neighbor region, also can define the contour precision and contour key points actively as snake is growing up.This dissertation mainly engages in the research of the theories and techniques of 3-D reconstruction and processing of reconstructed models. Firstly, the key techniques of reconstrction from contours are analized. Cylinder growing method is used to determine the linking relationships of contours between slice-images. Branching problem is a difficulty in surface reconstruction from slice contours. This dissertation proposes an algorithm to solve the problem by constructing transition contours using Active Contour Model. The algorithm considers the transition contours construction as a growing process, so it is based on higher layer knowlege and can ensure that transition contours are similar to trunk contours and branch contours, and also reconstructed transition surfaces at branch points are smooth. The contours are connected using adjacent contours synchronous marching algorithm. Secondly,inthis dissertation also introduces a new concept of "Connected Surface Projection Region ",and proposes a new algorithm for surface reconstruction based on projection. The zero isosurface is extracted using MT(Marching Tetrahedras) algorithm. In accordance with the intersection feature between isosurface and voxel, this dissertation made improvement in MT algorithm. Lastly, an arbitrary bone model fracture simulation method based on Delaunay triangulation is presented.This dissertation also studies the transformation between reconstructed surface model and solid model. For surgery tools models, this dissertation presents an algorithm to transform models constructed in solid modeling system to the developed virtual system in which surgery tools models can be constructed conveniently, accurately and parameterizely.The constructed models can have high level third dimension effect. For slice-imagings, this dissertation gives an algorithm for rebuilding solid model from triangulated patch surface model and the rebuilding processing function as an important function in reverse engineering has been added to 3D-Modeler system, which is a feature solid modeling system developed by CAD Lab of DUT, so the reconstruted bone model can be further processed in the CAD system.To enhance the immersion of the vir...
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