We use cookies to improve your experience with our site.

嵌入任意三角网格的柔性体的稳定实时手术切割仿真

Stable Real-Time Surgical Cutting Simulation of Deformable Objects Embedded with Arbitrary Triangular Meshes

  • 摘要: 手术仿真系统需要模拟柔性体的变形和切割.基于自适应八叉树网格的切割方法将柔性体嵌入八叉树网格中,切割工具轨迹附近的八叉树网格单元被递归细分.变形仅针对八叉树网格实施,因此退化单元导致变形计算不稳定问题被避免了.以前的相关研究工作忽略了生物组织和器官往往包含复杂的内部结构这一事实.针对上述问题,将柔性体构造成嵌入八叉树网格的体素,体素之间由链接相连.被切割工具扫过的链接被切断,而柔性体的面网格由切断的链接构造出来.提出了两种将三角网格嵌入上述柔性体模型的新方法.第一种方法称为面网格嵌入法.该方法适用于任意三角网格,但嵌入的结构不具有物理属性.第二种方法称为物质区域嵌入法.该方法将三角网格包围的区域赋予物理属性,但要求三角网格必须水密,不自相交,并且最小特征尺度小于体素的尺度.仿真算法在仿真运行前将一些局部特征事先计算好,以提高仿真的运行效率.仿真实验表明,我们设计的方法可以正确切割嵌入内部结构的柔性体,并保持柔性体和内部结构切割效果的一致性.切割产生的内部结构碎片可以和柔性体一起正确变形.

     

    Abstract: Surgical simulators need to simulate deformation and cutting of deformable objects. Adaptive octree mesh based cutting methods embed the deformable objects into octree meshes that are recursively refined near the cutting tool trajectory. Deformation is only applied to the octree meshes; thus the deformation instability problem caused by degenerated elements is avoided. Biological tissues and organs usually contain complex internal structures that are ignored by previous work. In this paper the deformable objects are modeled as voxels connected by links and embedded inside adaptive octree meshes. Links swept by the cutting tool are disconnected and object surface meshes are reconstructed from disconnected links. Two novel methods for embedding triangular meshes as internal structures are proposed. The surface mesh embedding method is applicable to arbitrary triangular meshes, but these meshes have no physical properties. The material sub-region embedding method associates the interiors enclosed by the triangular meshes with physical properties, but requires that these meshes are watertight, and have no self-intersections, and their smallest features are larger than a voxel. Some local features are constructed in a pre-calculation stage to increase simulation performance. Simulation tests show that our methods can cut embedded structures in a way consistent with the cutting of the deformable objects. Cut fragments can also deform correctly along with the deformable objects.

     

/

返回文章
返回