Research On The Solid Texture Synthesis Method Of The Soft Tissue Of Liver Based On Multiplexing Calculation

The virtual surgery system, which uses computer graphics and virtual reality technology to simulate the real surgical environment and guides doctors to perform the surgeries, is a rapidly developing subject in recent years. Realistic rendering is an important part of virtual surgery system, however, traditional 2D texture mapping method will cause the joint deformation appearance, and it cannot show the difference of inner texture of organs in different sections, solid texture can perfectly perform 3D texture informations. Existing solid texture synthesis methods have some problems: low accuracy, time consuming and cannot satisfy the needs of high accuracy and real-time in virtual surgery. Aiming at the problems above, we regard the virtual liver surgery as the object of research, take the visible human project (VHP) liver sections as the data sources, and extract the liver contours to establish a 3D liver model. Then use multiplexing calculation to synthetize the solid texture of liver and map the texture to the established liver model, which increases the realistic feel of virtual surgery, realize the cutting operations and users can see the inner texture by cutting the liver model, improves the interactive performance of the system. This paper’s mainly works includes:(1) We do some preprocessing to the VHP sections, and present a liver contours segmentation method which based on Bezier curves technology and traditional floodfill algorithm. Use the contours data and the VTK toolkit to achieve the 3D reconstruction, use constraint Delaunay tetrahedroning method to materialize the surface model, and achieve cutting operations according to tetrahedron splitting algorithm.(2) Aiming at the problems that tradition solid texture synthesis method are time consuming, use a dynamic ROI selection method to build solid texture samples and realize visualization. Then we discuss the difference between the solid texture space and the 2D space, and improve the 2D multiplexing method to use in solid texture space. Present the iteration condition judgment method and overlapping area process method with solid texture cubes, multiplexing synthetize the solid texture of liver, our method increases the speed of solid texture synthetizing and we present an improved S3TC algorithm to condense the synthetized solid texture.(3) We get the distribution of the surface tetrahedron of liver model, calculate 3D texture coordinate by judging the location relationship between every vertex of surface tetrahedron and the solid texture cubes, and achieve the solid texture mapping. Then, we calculate the inner point sets of the triangular patches to realize the refinement of the texture, users can see the inner texture by cutting the liver model. Make texture atlas according to regulation that the height of triangular bounding box decrease gradually to increase the solid texture mapping efficiency.Finally, we design and develop a virtual liver surgery experimental system, which integrates the model, solid texture and algorithms described above. Then we gives experimental results and summarize the works have done, analyze the future works.The experimental results show that the virtual liver surgery system we established can realize the segmentation of images and the reconstruction of 3D models easily, synthetize the solid texture with high accuracy rapidly, and users can interact with the liver model through the mouse, cutting the liver model to look over the texture inside the liver. Our research has important implications for the research of texture synthetizing in virtual surgery, with a wide range of application prospects.