虚拟骨科手术中触觉交互建模方法综述

虚拟骨科手术可以让骨科医生使用多种虚拟骨科手术器械在三维重建的骨性解剖结构模型上进行骨科手术操作和 训练。力触觉交互在骨科手术中起着不容忽视的作用,如何在骨科手术模拟中实现真实快速的触觉交互,已成为近年来 虚拟骨科手术研究的热点。文章主要对现有的骨科手术模拟系统中用到的触觉交互模型进行了研究、分类和总结,分析 了现有的一些模型的特点和不足,并展望了骨科手术系统中未来力触觉交互的发展。     

基于力反馈的虚拟脊柱手术模拟系统的构建

针对医学手术排练演习和手术教学开发了虚拟脊柱手术模拟平台。在该平台上能够根据手术的真实环境,模拟常用手术器械和脊柱结构,实现人机实时交互。详细介绍了系统的硬件环境参数,并基于3DS MAX的建模和力触觉渲染引擎CHAI 3D进行仿真。仿真实验结果表明,基于力反馈的虚拟脊柱手术模拟系统可以有效地模拟脊柱手术时的力反馈状态,帮助医师进行脊柱手术术前训练,并适用于高校的医学教学和医疗机构人员的培训。     

实时多组织虚拟手术的反馈力模拟

为了在虚拟下颌整形手术系统中提供实时和真实的触觉交互,分别构建了基于虚拟中介平面的推操作触觉模型、基于粘附力的拉操作触觉模型和基于非线性粘弹性的针刺触觉模型,以模拟皮肤拉钩、整形镊和针的典型手术操作;同时通过相邻组织间的动态触觉约束建立了多组织联合形变模型,以避免表面弹簧-质点模型形变过程中可能出现的表面间相互穿透的异常现象;并进一步将触觉交互模型和多组织形变模型集成于虚拟下颌手术系统,从而为医生提供一个手术训练的虚拟平台.触觉感知和交互效率的实验结果表明,通过触觉交互识别皮肤、肌肉和骨骼能够获得较高的识别正确率,并能提供实时的触觉和视觉交互体验.     

面向上颌骨骨折复位手术的虚拟系统设计

基于3D计算机触觉视觉交互(CHAI3D)和开放图形库(Open GL)等开源软件,设计了针对上颌骨复位手术的仿真系统。使用真实病例的CT图像搭建虚拟场景,通过Geomagic力反馈设备对虚拟模型进行三维操作并输出触觉反馈。在原有单点碰撞算法的基础上,提出了使用多个中介代理的多点碰撞算法,避免了虚拟手术工具的手柄插入虚拟器官的不实仿真;通过力反馈设备对头颅骨模型进行选择、移动和旋转,模拟手术中对头颅骨的移动和放置。系统可用于训练医学院学生,也可用于复杂手术的术前规划。     

一种虚拟手术二维力觉交互装置的力学模型

对力交互装置在虚拟手术巾有着广泛的应用,作为基础研究,提出一种二维力觉交互装置的反馈力模型,通过模拟虚拟器械与肌肉组织和骨骼碰撞时的受力情况,验证模型的合理性。首先,根据人体组织的生物力学性能,参照Kamopp模型和胡克定律提出了系统的反馈力模型;然后针对系统的性能指标,通过对肌肉和骨骼两种组织的碰撞实验,验证了设备在虚拟手术过程中反馈力实现效果。仿真结果显示,反馈力方法能较准确地仿真力的变化,准确地感知骨骼的位置,对于虚拟手术系统的实用性具有重要意义。     

虚拟手术中血流特效场景仿真的研究

血流特效场景可以增强虚拟手术的真实感。虚拟手术中的血流特效场景包括了有交互的血液模拟及血管壁模拟。首先基于光滑粒子流体动力学,使用Physx物理引擎模拟血液流动的物理形态,并利用Screen Space Flow算法对血流表面进行实时渲染。然后基于质点-弹簧模型,提出使用Physx物理引擎模拟可交互、有弹性形变及可切割的血管壁。最后实现两个实验场景:场景一实现肺动脉内大规模血液流动的特效;场景二实现在用户交互下的血管壁形变和切割,并通过触发事件实现血管壁破裂流血的特效。实验结果表明,该血流及血管壁模拟方法在40 000个粒子下仍能保证实时绘制,满足虚拟手术的需求。     

虚拟手术训练力觉交互技术的现状与趋势

虚拟手术训练系统对于解决传统的手术训练存在的问题,提高临床手术的安全性和治愈率起着积极的作用。在介绍目前虚拟手术训练系统发展现状的基础上,阐述了虚拟手术训练交互装置的研究进展,针对目前虚拟手术训练交互装置存在的问题,提出了建设性的解决方案,并分析了其发展趋势和应用前景。     

Win32下网络蜜罐的设计与VC++实现

在Windows 2000下用VC++实现一个Telnet服务的蜜罐系统,该系统虚拟Linux系统下的Telnet服务,由通信交互模块、响应模块和监听记录模块三部分组成,其中通信交互模块和响应模块构成了虚拟Telnet服务.     

基于VTK的医学三维图像模型构建与切割

虚拟外科手术是医学领域的一个重要研究方向。基于面绘制和体绘制两种可视化算法实现医学图像的三维模型重建,针对不同重建模型分别实现虚拟任意切割：面切割和体切割,并讨论了虚拟切割的交互操作实现方法。用VTK(Visualization Toolkit)初步实现了模拟手术系统中的虚拟切割脊柱体功能。     

基于杆-质点模型实现的脑膜瘤术前训练系统

脑膜瘤是中枢神经系统最为常见的原发性肿瘤,手术摘除是该疾病的首选治疗方案。脑神经外科疾病发病紧急、专家少、会诊难度大,且病灶易与周围组织粘连,手术操作空间狭小。因此,设计术前培训系统帮助医生模拟手术过程是非常必要的,而如何实时模拟手术过程中手术器具与脑膜瘤及周边正常脑组织的交互力是亟待解决的问题。采用改进的杆-质点模型建立脑膜瘤摘除过程中手术器具与病灶的交互过程模型,实时计算交互力,并通过手控器反馈给医生,使医生能够真实感受手术过程。基于C#、Unity 3D 等软硬件系统构建虚拟手术系统平台进行实验,验证了所提出的方法具有实时性,可以满足神经外科手术需求。     

膝关节镜手术仿真训练系统设计

利用虚拟现实技术建立的手术仿真训练系统,可以大大减少内窥镜等疑难手术的培训时间并节约昂贵的动物实验费用.为满足膝关节镜手术训练的需要,针对虚拟手术仿真的技术特点,提出了关于虚拟现实技术的膝关节镜手术仿真训练系统的设计,主要对系统体系结构、软件结构、功能模块和系统界面的设计和技术实现进行了研究,最终实现了一个支持双手操作的手术仿真训练系统.实践证明,系统能逼真地模拟手术的流程,取得了良好的训练效果.     

Computer-based virtual reality simulator for phacoemulsification cataract surgery training

Recent research in virtual reality indicates that computer-based simulators are an effective technology to use for surgeons learning to improve their surgical skills in a controlled environment. This article presents the development of a virtual reality simulator for phacoemulsification cataract surgery training, which is the most common surgical technique currently being used to remove cataracts from the patient’s eyes. The procedure requires emulsifying the cloudy natural lens of the eye and restoring vision by implanting an artificial lens through a small incision. The four main procedures of cataract surgery, namely corneal incision, capsulorhexis, phacoemulsification, and intraocular lens implantation, are incorporated in the simulator for virtual surgical training by implementing several surgical techniques. The surgical activity that are applied on the anatomy of the human eye, such as incision, grasping, tearing, emulsification, rotation, and implantation, are simulated in the system by using different types of mesh modifications. A virtual reality surgical simulator is developed, and the main procedures of phacoemulsification cataract surgery are successfully simulated in the system. The simulation results of the training system show that the developed simulator is capable of generating a virtual surgical environment with faithful force feedback for medical residents and trainees to conduct their training lessons via the computer using a pair of force-feedback haptic devices. In addition, the successful simulation of the mesh modifications on the human eyeball with visual realism and faithful force feedback throughout the surgical operation shows that the developed simulator is able to serve as a virtual surgical platform for surgeons to train their surgical skills.     

舰船轮机虚拟训练系统开发技术研究

针对轮机专业舰员岗前培训的需要,设计实现了基于计算机局域网的舰船轮机虚拟训练系统。将系统分为装备示教模块和装备虚拟训练模块两大部分,可实现装备结构组成、工作原理、维护保养的计算机示教功能和装备故障诊断、虚拟操纵的模拟训练功能;介绍了系统实现过程中的关键技术及实现方法。使用结果表明系统可有效提高舰员熟悉和掌握装备的水平。     

A Review of Computer-Generated Simulation in the Pedagogy of Cataract Surgery Training and Assessment

Virtual reality simulation is no longer an unusual term due to its application in aviation, industry, medicine, and military. The limitation of animal model in wet-lab training has necessitated the discovery of new training tools. Criteria-based surgical training can be simulated in a protected environment virtually by using computer for medical assessment and evaluation. This article reviews the pedagogical value of various virtual reality cataract surgery simulators developed, in surgical skill education and evaluation. Literature searches were conducted in ACM, IEEE Xplore, PubMed, Taylor & Francis, SciVerse, and Springer Link, covering the period from 1990 to the present. The published literature that presents methodological approach in the creation of simulation and feasibility study on performance evaluation system were examined. Evidence from the study proves that high-fidelity simulation is capable of providing objective surgical training and distinguishing the level of competency between students, residents, and surgeons in cataract surgery. Standardization and classification of training module according to the proficiency of surgical skills are considered necessary in improving validity of simulators as part of curriculum in medical education.     

Visuohaptic Simulation of Bone Surgery for Training and Evaluation

Visual and haptic simulation of bone surgery can support and extend current surgical training techniques. The authors present a system for simulating surgeries involving bone manipulation, such as temporal bone surgery and mandibular surgery, and discuss the automatic computation of surgical performance metrics. Experimental results confirm the system's construct validity     

基于Quest3D的钻床加工虚拟教学系统的研究

针对培训系统要求人机交互界面好以及沉浸感强等特点,在钻床教学系统开发中采用实时3D建构工具Quest3D,提出了一种针对钻床教学培训的虚拟现实系统的开发方案,将虚拟现实系统分为三维显示模块,运动控制模块,场景交互模块和场景声控模块等,通过Quest3D的图形编程使得整个系统开发周期缩短,运行效率提高。成功将三维场景虚拟交互技术运用于钻床教学培训系统中。     

虚拟手术中软组织切割模型研究进展*

虚拟手术仿真训练系统是虚拟现实的重要应用,能够克服真实传统手术中资源少、训练不方便和可重复操作性差等问题。软组织切割是虚拟手术仿真训练系统中的重要组成部分,也是手术中最常见的操作。软组织切割模型建立的质量如何,直接决定了虚拟手术仿真的精度度和仿真度。为更好地对软组织切割模型进行深入探索,分析了虚拟手术仿真中软组织切割的研究难点。针对当前十四种有代表性的切割模型进行了研究,在此基础上对这些模型的优缺点进行了比较,并对软组织切割模型的发展趋势进行了展望。     

Mechanical modeling of a beating heart for a cardiac palpation training system

In cardiac plastic surgery, the cardiac surgeon touches the cardiac muscle to diagnose the patient's heart that may be diseased due to infarction or dilate cardiomyopathy to determine the regions where it needs plastic surgery. In other words, the cardiac surgeon needs to recognize the mechanical characteristics of the thin muscle regions by the haptic sensitivity of his/her fingertips. Cardiac images available before cardiac surgery could enable a qualitative estimation of the patient's heart. However, cardiac palpation is the only accurate way for making surgical plans for ventricular plastic surgery in the operating theater. Since young inexperienced cardiac surgeons have few occasions to perform cardiac palpation, even in operation cases, a cardiac palpation training system is highly desired. The training system for a cardiac palpation system we have developed consists of a virtual heart based on human left ventricular magnetic resonance images and a one-dimensional manipulator as a haptic device. Mechanical properties of the cardiac muscles of a pig and a dog are embedded into the virtual heart linked to a Windkessel model for the systemic circulation. Our experiments show that the developed training system enables users to feel the elasticity of the cardiac muscle wall through the manipulator in real-time.     

虚拟显微白内障手术系统人机交互接口设计

基于虚拟现实技术的显微白内障手术仿真训练系统对显微环境下眼科手术操作培 训具有重要的意义。为此,设计并搭建了一套具有高度沉浸感的虚拟显微白内障手术训练系统 的软硬件环境。硬件部分系统以 HTC Vive,Geomagic Touch X 为硬件基础,设计手术器械转换 接口以搭建高保真手术操作环境;软件部分采用基于位置动力学方法(position-based dynamics) 模拟手术过程中眼角膜软组织的变形、穿刺及缝合操作,并采用 GPU 并行计算对手术仿真过程 进行加速。最后,实验结果表明该系统可以实现自然的显微眼科手术人机交互环境,使年轻医 师获得高沉浸感的真实手术训练体验,从而达到一定的培训效果。