共查询到18条相似文献,搜索用时 171 毫秒
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实时交互式软组织切割与变形计算模型 总被引:1,自引:0,他引:1
为提高虚拟手术模拟的交互性与实时性,提出一种软组织实时切割与变形计算模型.该模型以混合有限元模型为基础,根据手术过程中不同区域的交互特点,利用GPU加速手术区域的切割与变形计算;同时,对非手术区域的软组织因交互而引起的实时变形可通过选择性相乘的方法快速实现.实验结果充分证明,该计算模型可以灵活有效地实现实时软组织的交互切割与变形模拟. 相似文献
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为了得到虚拟外科手术中人体软组织的实时变形仿真,采用了基于模态分析的模型约简方法,同时结合了GPU加速技术,实现了人体软组织的实时仿真计算,为虚拟手术提供了良好的人机交互.模型约简以有限元理论为基础,将软组织模型的动力学方程投射到约筒子空间,减少系统自由度.在实时仿真过程中,首先需在子空间中对低维动力学模型进行数值计算,然后利用GPU通用计算技术来加速重建原始空间中的形变向量.以心脏大变形实时仿真为例,验证方法的性能,实验结果表明心脏的变形仿真可以在很高的刷新率下运行.提出的模型约简和GPU加速方法,为人体软组织的变形实现了实时仿真,为虚拟手术提供了理论基础和技术支撑. 相似文献
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为满足虚拟手术中软组织变形的精确性和实时性要求,提出一种基于复合模型的软组织变形模拟算法。该复合变形模型包括复合网格的建立,复合网格中粗糙体网格应用有限元模型,精细表面网格应用基于位置动力学模型,通过变形计算流程实现变形模拟。复合模型与传统的有限元模型和基于位置的动力学模型相比,变形的精确性和实时性取得了更好的平衡。通过变形实例,表明复合模型对于实例模型也具有很好的展示效果。 相似文献
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软组织模型的变形计算是虚拟手术中的一个重要组成部分,尽管大量的研究一直致力于模拟软组织的形变,软组织变形的建模仍然是一个具有挑战性的问题。从仿真实时性的角度,提出了一种基于混合有限元模型的软组织模型解决方案。实验仿真表明该方案提高了计算效率,节省了大量内存,实验仿真表明达到了实时性仿真水平。 相似文献
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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。 相似文献
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Interaction model between elastic objects for haptic feedback considering collisions of soft tissue 总被引:5,自引:0,他引:5
Kuroda Y Nakao M Kuroda T Oyama H Komori M 《Computer methods and programs in biomedicine》2005,80(3):216-224
The simulation of organ–organ interaction is indispensable for practical and advanced medical VR simulator such as open surgery and indirect palpation. This paper describes a method to represent real-time interaction between elastic objects for accurate force feedback in medical VR simulation. The proposed model defines boundary deformation of colliding elements based on temporary surface forces calculated by temporary deformation. The model produces accurate deformation and force feedback considering collisions of objects as well as prevents unrealistic overlap of objects. A prototype simulator of rectal palpation is constructed on general desktop PC with a haptic device, PHANToM. The system allows users to feel different stiffness of a rear elastic object located behind another elastic object. The results of experiments confirmed the method expresses organ–organ interaction in real-time and produces realistic and perceivable force feedback. 相似文献
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Yongmin Zhong Bijan Shirinzadeh Julian Smith Chengfan Gu 《Journal of Visual Languages and Computing》2012,23(1):1-12
This paper presents a new methodology to conduct modelling and analysis of soft tissue deformation from the physicochemical viewpoint of soft tissues for surgery simulation. The novelty of this methodology is that soft tissue deformation is converted into a reaction-diffusion process coupled with a mechanical load, and thus reaction-diffusion of mechanical load and non-rigid mechanics of motion are combined to govern the dynamics of soft tissue deformation. The mechanical load applied to a soft tissue to cause a deformation is incorporated into the reaction-diffusion system and consequently distributed among mass points of the soft tissue. An improved reaction-diffusion model is developed to describe the distribution of the mechanical load in the tissue. A generic finite difference scheme is presented for construction of the reaction-diffusion model on a 3D tissue surface. A gradient method is established for derivation of internal forces from the distribution of the mechanical load. Real-time interactive deformation of virtual human organs with haptic feedback has been achieved by the proposed methodology for surgery simulation. The proposed methodology not only accommodates isotropic, anisotropic and inhomogeneous materials by simply modifying diffusion coefficients, but also accepts local and large-range deformations simultaneously. 相似文献
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Cotin S. Delingette H. Ayache N. 《IEEE transactions on visualization and computer graphics》1999,5(1):62-73
We describe a novel method for surgery simulation including a volumetric model built from medical images and an elastic modeling of the deformations. The physical model is based on elasticity theory which suitably links the shape of deformable bodies and the forces associated with the deformation. A real time computation of the deformation is possible thanks to a preprocessing of elementary deformations derived from a finite element method. This method has been implemented in a system including a force feedback device and a collision detection algorithm. The simulator works in real time with a high resolution liver model 相似文献
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Yoshimitsu Aoki Shuji Hashimoto Masahiko Terajima Akihiko Nakasima 《The Visual computer》2001,17(2):121-131
We propose a prototype of a facial surgery simulation system for surgical planning and the prediction of facial deformation.
We use a physics-based human head model. Our head model has a 3D hierarchical structure that consists of soft tissue and the
skull, constructed from the exact 3D CT patient data. Anatomic points measured on X-ray images from both frontal and side
views are used to fire the model to the patient's head.
The purposes of this research is to analyze the relationship between changes of mandibular position and facial morphology
after orthognathic surgery, and to simulate the exact postoperative 3D facial shape. In the experiment, we used our model
to predict the facial shape after surgery for patients with mandibular prognathism. Comparing the simulation results and the
actual facial images after the surgery shows that the proposed method is practical. 相似文献
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Haptics on 3D deformable models is a challenge because of the inevitable and expensive 3D deformation computation. In this
paper, we propose a new technique that extends the conventional rigid geometry images approach proposed by Gu et al. [9].
Our approach not only flattens the geometry, but also helps to accomplish deformation in an effective and efficient manner.
Our approach is suitable for haptics computing, as it performs the deformation on the geometry map itself thereby avoiding
the expensive 3D deformation computation. We demonstrate construction of the deformable geometry map representation and its
application utilizing practical methods for interactive surgery simulation and interactive textile simulation. 相似文献