Research Of Haptic Related Computation In Virtual Liver Surgery

With the development of computer graphics, virtual surgery plays a more and more important role in modern medicine surgery training. Traditional surgery training which operates on corpses and animals not only cost too much, but also causes disaccord in the aspect of physical and physiological characteristics. These impede the efficiency of the operation training seriously. Virtual surgery gets rid of these problem by provides users with real scenes which simulate the surgery operation. Virtual surgery greatly promotes the promotion and training of complex surgeries, it makes the modern surgery training cheaper and more reliable and has great practical prospect and research value.Virtual surgery involves multiple subjects such as computer graphics, physics, physiology and computer vision, and it is a challenging research topic. Haptic interaction function is the key to make a distinction between virtual surgery systems and other training methods. In the process of operation, users contact with the virtual scene and complete the operation by manipulating the haptic interaction device. Therefore, haptic related calculation is an important part of virtual surgery system.This paper studied the haptic related calculation of the virtual liver surgery, including the liver surface cutting area calibration, soft tissue deformation and liver parenchyma splitting simulation problems.In the aspect of liver surface cutting area calibration simulation, this paper generalized the problem as the computation of the geodesic on the triangle mesh. Then studied several geodesic algorithms on triangle mesh, analyzed their time complexity. The iterative segmentation geodesic algorithm is improved, and be applied to the liver surface cutting area calibration simulation with reality effect.In the aspect of soft tissue deformation, this paper discussed the mass-spring model and the shape matching method. The mass-spring model is selected to simulate the deformation of the liver capsule. The Fast lattice shape matching method is improved, and be used to simulate the deformation of the liver. The simulation is similar to the real operation.In the aspect of the liver parenchyma splitting, this paper introduced several practical methods from the aspects of geometric model and motion model. Based on the characteristic of liver surgery splitting, a simplified method is proposed. It updates the normal vector of vertices and disconnect the relations between the particles and particles in different areas while splitting. The simplified method is applied to the virtual liver surgery system, realistically simulated the liver parenchyma splitting.