Direct Visuo-Haptic 4D Volume Rendering Using Respiratory Motion Models
Direct Visuo-Haptic 4D Volume Rendering Using Respiratory Motion Models
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DOI：
10.1109/toh.2015.2445768
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发表时间：
2015-10-01
影响因子：
2.9
通讯作者：
Handels, Heinz
中科院分区：
文献类型：
--
作者：
Fortmeier, Dirk;Wilms, Matthias;Handels, Heinz
本文介绍了呼吸运动下的虚拟患者模型的直接视觉-触觉4D体绘制方法。基于患者特定的4D CT图像数据序列来计算呼吸模型。虚拟患者模型通过对由时变位移场扭曲的参考CT图像进行基于射线投射的渲染来实时可视化，所述时变位移场在运行时使用运动模型来计算。此外，通过使用以高渲染速率计算的位移来将触觉装置的位置平移到参考CT图像的空间中，来提供与动画虚拟患者模型的触觉交互。这个概念被应用到虚拟触诊和虚拟可弯曲针的插入的触觉模拟。为了这个目的，提出了适用于实时的不同运动模型，并且将所述方法集成到针穿刺训练仿真框架中，所述针穿刺训练仿真框架可用于肝脏中的模拟活检或血管穿刺。为了确认实时的适用性，所得到的框架的性能分析。结果表明，所提出的方法实现平均更新率约2,000 Hz的触觉模拟和交互式帧速率的体积渲染，因此非常适合呼吸运动下的虚拟患者的视觉-触觉渲染。
This article presents methods for direct visuo-haptic 4D volume rendering of virtual patient models under respiratory motion. Breathing models are computed based on patient-specific 4D CT image data sequences. Virtual patient models are visualized in real-time by ray casting based rendering of a reference CT image warped by a time-variant displacement field, which is computed using the motion models at run-time. Furthermore, haptic interaction with the animated virtual patient models is provided by using the displacements computed at high rendering rates to translate the position of the haptic device into the space of the reference CT image. This concept is applied to virtual palpation and the haptic simulation of insertion of a virtual bendable needle. To this aim, different motion models that are applicable in real-time are presented and the methods are integrated into a needle puncture training simulation framework, which can be used for simulated biopsy or vessel puncture in the liver. To confirm real-time applicability, a performance analysis of the resulting framework is given. It is shown that the presented methods achieve mean update rates around 2,000 Hz for haptic simulation and interactive frame rates for volume rendering and thus are well suited for visuo-haptic rendering of virtual patients under respiratory motion.