虚拟手术中的软组织变形技术研究

发布时间：2018-06-04 00:38

本文选题：虚拟手术 + 变形计算　；参考：《中国科学技术大学》2015年硕士论文

【摘要】：虚拟手术系统是虚拟现实技术和现代医学结合的产物,通过建立集成有视觉、触觉、听觉、嗅觉等多感知的虚拟手术环境,给予医生逼真的手术场景,实现手术培训教学和手术方案三维构思。一个典型的虚拟手术系统包括组织的建模、碰撞检测、变形计算、切割计算、图形绘制和触觉绘制。目前虚拟手术系统研究中存在仿真精度和速度之间的矛盾,如何平衡这对矛盾是研究人员一直以来面临的难题。本文围绕着现存的技术难题对手术仿真中的常用的且具有代表性的变形计算展开深入研究,主要工作如下：首先,从力学角度分析了软组织生物力学特性,分别介绍了人体软组织的线弹性模型和粘弹性模型,及其适用环境。其次,采用三维Delaunay网格生成算法对软组织模型进行网格划分,对于网格质量的判断,本文提出了一种快速有效的判断准则。再次,针对有限元法处理软组织变形计算实时性差的问题,采用组织模型局部进行有限元计算代替整体的思路。并利用数据结构中的“有向图矩阵”,完成了对软组织的局部模型快速提取工作。最后,对软组织模型进行变形仿真,并对有限元计算进行了一定的优化,对比实验证明,在维持精度基本不受影响的前提下,提升了计算速度。
[Abstract]:Virtual operating system is the product of virtual reality technology and modern medicine. Through the establishment of virtual operating environment integrated with visual, tactile, hearing, and smell, it gives the doctor realistic operation scene, and realizes the operation training teaching and the three dimensional conception of the operation scheme. A typical virtual operation system includes organization modeling, collision Detection, deformation calculation, cutting calculation, graphic drawing and tactile rendering. There is a contradiction between simulation precision and speed in the research of virtual surgery system. How to balance the contradiction is a difficult problem that the researchers have been facing. This paper revolves around the commonly used and representative deformation in the simulation of existing technical problems. The main work is as follows:
First of all, the biomechanical properties of soft tissue are analyzed from mechanics point of view. The linear elastic model and viscoelastic model of human soft tissue are introduced respectively and their applicable environment.
Secondly, the 3D Delaunay grid generation algorithm is used to mesh the soft tissue model, and a fast and effective criterion for judging the quality of the grid is proposed.
Thirdly, in view of the problem that the finite element method is used to deal with the poor real-time performance of soft tissue deformation, the idea of replacing the whole with the local finite element calculation of the organization model is adopted. And the "directed graph matrix" in the data structure is used to complete the rapid extraction of the local model of the soft tissue.
Finally, the soft tissue model is simulated and the finite element calculation is optimized. The comparison experiment shows that the calculation speed is improved under the premise that the maintenance precision is not affected basically.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TP391.9;R616

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