基于点云模型的虚拟手术系统建模及碰撞检测

摘要

建模与碰撞检测算法是虚拟手术具有良好实时性的前提。通过 CT得到病人身体患部的点云数据，再基于八叉树剖分算法，采用层次包围球结构，对手术部位的软组织及器官进行建模。为了提高碰撞检测的实时性，将手术器械物理模型简化为一个小球或一条直线与软组织交互，而几何模型保持不变，这样在不影响虚拟手术的视觉效果同时又提高了碰撞检测的速度。实验结果表明，算法能准确检测出虚拟手术器械与虚拟模型接触的点，而且碰撞检测实时性显著提高，简化后的平均碰撞检测时间仅为虚拟手术的快速碰撞检测算法中未简化的方法平均时间的10%。%Modeling and collision detection algorithm is the premise of the real-time in virtual surgery. Here,we extract the CT point cloud data from patients.Then,we model for soft tissues and organs based on the algorithm of octree subdivision and hierarchical structure of bounding sphere.In order to im-prove the real-time of the collision detection,the physical models of the surgical instruments are simpli-fied to balls or lines.The geometry remains unchanged,and it thus does not affect the operation of the virtual visual while the speed of the collision detection is improved greatly.The experimental results show that the algorithm can accurately detect the point of virtual contact with the virtual model of surgi-cal instruments,and collision detection in real-time have increased considerably.Simplified average colli-sion detection time is 10% of the original.