Software For Virtual Surgery Geometric Modeling And Deformation Algorithms

As an interdiscipline research topic, virtual surgery incorporates the researches about Computer Technology, Computer Graphics, Sensor Technology, Biomechanics, Modern Medicine, Image Processing, Computer Vision, Robotics, Scientific Computing Visualization, etc. The object of surgery simulation system research is to use the computer technology to simulate and instruct each step of process which the medicine surgery involves. As a whole, virtual surgery system contains all of the periods of the operation. In archiving the aim of the surgeiy, virtual surgery system provides with the guiding in process of the surgery and the planning, teaching, training and checking etc. of it. The research of virtual surgery has the broadly potential application.Based on analyzing the constitutions of virtual surgery system, this thesis thoroughly studies two core technology of virtual surgery about soft-tissue geometrical modeling and deformation methods. For geometrical modeling, this thesis focuses on the limitation of changing model, and presents a units modeling algorithm for medical soft-tissue. Firstly, this algorithm introduces unit modeling space to get unit model. Then the unit model is controlled to enlarge and reduce the scale by proportion parameters. So a new model is obtained according to the component of parameters in three directions of X, Y, Z. The experiment shows the model implements by the algorithm greatly improves the general property. As for deformation, this paper presents an attenuation deformation algorithm based on unitization model to solve the problem which is difficult to realize local deformation by adjusting controlling-vertices in Free-Form-Deformation etc. of soft tissue. The method transforms the collision point three-dimension world coordinate into two-dimension vertex coordinate of triangle grid, controls attenuation change of vertical offset in region by defining adaptive deformation region within the center of collision point to lead to deform. The offset implements parabolic attenuation with designing proper attenuation function. It was found that the effectiveness of parabolic attenuation deformation is obtained accurately in local region, and the real-time is increased further more, the space-time costs are decreased.The conclusion is addressed at the end of this paper. Future researches will pay more attention to several other aspects according to the experience and shortage in design and realization of existing algorithm.