基于改进碰撞检测算法的肝门静脉结扎仿真

为了对虚拟肝脏手术中肝门静脉的结扎进行仿真,提出了一种改进的碰撞检测算法。改进的碰撞检测算法主要包括三个方面:缝合线的自碰撞检测、缝合线的运动分解,以及缝合线与肝门静脉模型的碰撞检测。缝合线的模拟采用跟踪控制点FTL算法,采用包围球法对缝合线进行自碰撞检测;提出运动分解方法来防止缝合线发生自穿透;将包围球法和空间网格划分法相结合,实现缝合线和肝门静脉之间的碰撞检测;同时,肝门静脉的形变采用设置刚体核的几何模型来模拟,使用虚拟弹簧振子来实现结扎时的触觉反馈。将改进的碰撞检测算法运用到虚拟肝脏手术中,满足虚拟场景中真实感和实时性的要求。

Ligaturing simulation of liver blood vessels based on an improved collision detection algorithm

We propose an improved collision detection algorithm for ligaturing simulation of liver blood vessels in virtual liver surgery. The improved algorithm mainly includes three aspects: self collision detection of suture, motion decomposition of suture, and collision detection of suture and blood vessels. We employ the follow the leader (FTL) algorithm to configure the motion of suture, and temporary restrictions are set to achieve the suture’s “equivalent friction”. The bounding volume hierarchies (BVH) method increases the efficiency of suture’s self collision detection, and the motion decomposition method manages to prevent penetrations. The integration of the BVH method and the grid method can handle the collision detection of suture and liver blood vessels. Moreover, a rigid core is used to limit the deformation of liver blood vessels mesh, and a virtual mass spring is used to implement the haptic feedback of ligaturing simulation. The improved algorithm works well for the ligaturing simulation of liver blood vessels in virtual liver surgery.