Study On The Method Of Space Anistropic Hepatic Artery Solid Texture Synthesis

The virtual surgery system has a broad application prospect in the medical field.It uses computer graphics and virtual reality technology to provide rich and reality image information and guides doctors to perform surgery.Therefore,it is an important part of virtual surgery system to enhance the realistic of surgery.However,the traditional two-dimensional texture can only express texture information of organ surface,and fails to show the difference between different cutting sections texture of inner organ.The solid texture can present rich texture details of inner and surface of organ.Existing solid texture synthesis methods have some problems,such as low synthesis accuracy and over time-consuming.Aiming at the problem above,the thesis regards hepatc artery as the object of research and puts forward the example-based solid texture synthesis method.It uses the user-specified vector orientation to guide three-dimensional texture to synthesis,not only improve the realism of texture drawing,but also implement cutting operation.The core work of the paper is as follows:(1)The three-dimensional reconstruction of hepatic artery model.It proposes a semi-automatic segmentation method of hepatic artery contours which based on region growing and artificial participation algorithm.Use the visualization toolkit to achieve the three-dimensional reconstruction,and then isolate hepatic artery from reconstruction model.(2)The solid texture growth based on volumetric tensor fields.It comes up a construction method of tensor fields that use color attribute and arrow icons.Firstly,we use constraint Delaunay tetrahedroning method to materialize the surface model,and generate the depth field by color attribute,the gradient direction of direction field is the first vector field.Secondly,we use arrow icons to define the second vector field.The third vector field is the cross product of the first two vectors.Finally,we use Laplacian algorithm to interpolate vectors of the whole model to control orientation of texture.(3)Solid texture mapping and synthesis.Aiming at the solid texture feature of hepatic artery,the thesis puts forward a solid texture synthesis method based on solid texture examples to build correspond relationship between texture space and model space.It regards tetrahedron as synthesis unit and pastes three-dimensional texture examples along the user-defined volumetric tensor fields.At last,we make use of radial basis function to carry out cutting operation.This paper designs and develops the prototype experiment system of hepatic artery which integrates the algorithm described above.It also concludes the analysis and experiment result,and represents the work prospect of next phase.With prototype experiment system,users can easily observe the realistic solid texture of hepatic artery and interact with model to look over the texture inside the hepatic artery by the use of mouse.The thesis proposes the solid texture synthesis method of anistropic hepatic artery can realistically reflect the hierarchical structure of internal texture of hepatic artery.It not only has certain guiding significance in virtual surgery,but also plays an important reference for synthesising isotropic solid texture.