Research On Correlative Technology Of Virtual Gallbladder Surgery Simulation System

Traditional surgical training is restrained by lack of corpse source and ethics, so its efficiency is very low. In addition, for newly introduced medical equipment or rare cases,even operated by skilled surgeon, could also lead to the occurrence of medical accidents. To build a virtual surgery simulation system can effectively solve the problem. Using the computer, this system can simulate the deformation, cutting and stitching of the virtual surgery object (such as gallbladder, heart and other organs) generated by the surgical instrument in the virtual environment, and provides realistic tactile, visual, auditory feedback and so on.Based on research at home and abroad, this paper studies several key issues of the virtual surgery simulation system. It includes the establishment of the geometric model, the implementation of the collision detection algorithm, two kinds of optimization methods of collision detection algorithm, the establishment of physical model. In addition, We also set up a virtual surgery simulation system, and carried out the simulation experiment. The main contents are as follows:Firstly, we use 3ds Max software to build a gallbladder model and write program to read and store the information only related to the contour vertexes and facets of the gallbladder model in Visual C++ environment. After using this information to redraw based on the OpenGL graphics library, we can create a realistic model of the virtual gallbladder geometric through the later rendering such as adding light, calculating the vertex normal vector,anti-aliasing and so on.Secondly, we build S-AABB upper bounding box and S-S bottom bounding box. We complete the collision detection algorithm between surgical gallbladder and surgical instruments after testing each intersection of upper bounding box, bottom bounding box and geometry unit body. And then two optimization methods are put forwards. The one is to divide the collision object into different regions, and the other one is to forecast the element which will be possibly collided. we also effectively prove the effectiveness and rapidity of this collision detection and optimization methods by the experimental data.Thirdly, we use the spring-particle method, assuming virtual gallbladder constituted by spring and particle, and propose a local deformation method. By displacement of the particle during surgery, the deformation of surgery gallbladder can be simulated. Through the stress analysis of spring, we can simulate the feedback force generated during operation. Thus the physical model is established.Finally, this paper also carries a virtual surgery system simulation experiment to verify the correctness and reasonableness of geometric modeling,collision detection and physical modeling, and initially sets up a virtual simulation system.