基于无网格的软组织形变模型研究

Research on Soft Tissue Deformation Based the Meshless Model

软组织形变模型直接决定了虚拟手术仿真的实时性和准确性,同时决定着视觉渲染和力反馈的效果。目前,常见的软组织形变模型有质点弹簧模型和有限元模型,这两种模型都是基于网格技术的,在形变过程中容易出现网格的畸变和扭曲。基于此,笔者提出采用改进的无网格SPH方法进行软组织形变仿真,基本思想是在交互区域采用SPH方法进行精确计算,在传播区域通过将受力点的物理量乘以衰减系数进行近似计算。研究表明,此方法大大减少了参与计算的粒子数量,缩短了计算时间,提高了仿真实时性。

Soft tissue deformation model directly determines the real-time and accuracy of virtual surgery simulation,and determines the effect of visual rendering and force feedback.At present,the common soft tissue deformation models are the mass spring model and the finite element model.both of which are based on the mesh technology.These two methods are based on mesh technology,so mesh distortion and distortion are easy to occur in the process of deformation.Therefore,this paper proposes an improved meshless SPH method for soft tissue deformation simulation.In the interaction area,the SPH method is used for accurate calculation.In the propagation area,the physical quantity of the stress point is multiplied by the attenuation coefficient for approximate calculation.Research shows that this method greatly reduces the number of particles involved in the calculation,shortens the calculation time,and improves the real-time performance of simulation.