Leap Motion-based virtual reality training for improving motor functional recovery of upper limbs and neural reorganization in subacute stroke patients

Virtual reality is nowadays used to facilitate motor recovery in stroke patients. Most virtual reality studies have involved chronic stroke patients; however, brain plasticity remains good in acute and subacute patients. Most virtual reality systems are only applicable to the proximal upper limbs （arms） because of the limitations of their capture systems. Nevertheless, the functional recovery of an affected hand is most difficult in the case of hemiparesis rehabilitation after a stroke. The recently developed Leap Motion controller can track the fine movements of both hands and fingers. Therefore, the present study explored the effects of a Leap Motion-based virtual reality system on subacute stroke. Twenty-six subacute stroke patients were assigned to an experimental group that received virtual reality training along with conventional occupational rehabilitation, and a control group that only received conventional rehabilitation. The Wolf motor func- tion test （WMFT） was used to assess the motor function of the affected upper limb; functional magnetic resonance imaging was used to measure the cortical activation. After four weeks of treatment, the motor functions of the affected upper limbs were significantly improved in all the patients, with the improvement in the experimental group being significantly better than in the control group. The action perfor- mance time in the WMFT significantly decreased in the experimental group. Furthermore, the activation intensity and the laterality index of the contralateral primary sensorimotor cortex increased in both the experimental and control groups. These results confirmed that Leap Motion-based virtual reality training was a promising and feasible supplementary rehabilitation intervention, could facilitate the recovery of motor functions in subacute stroke patients. The study has been registered in the Chinese Clinical Trial Registry （registration number： ChiCTR-OCH- 12002238）.

Virtual Reality:A State-of-the-Art Survey

This paper presents a survey on virtual reality systems and provides an in-depth understanding toward the notion of immersion, according to the semantic meanings of the terms ＂virtual＂ and ＂reality＂. The paper analyses the structure and functions of a virtual reality system and takes the three dimensional display as the immersive medium to identify the key issues for construction of virtual environments. The paper also reviews the development of virtual reality technology and introduces new image processing techniques into the design of virtual reality systems and virtual environments.

An Image-Based Virtual Reality Prototype System

The most important goal of virtual reality is to create a virtual world by computers where users are allowed to view the environment and control the virtual objects interactively. naditionally virtual reality systems use 3D computer graphics to model and render a virtual environment in real time. However, this approach usually requires laborious modeling and expensive special-purpose rendering hardware. Image-based rendering is a new approach in composing a virtual environment in which a set of panoramic images is used to compose the virtual environment and walking in the space is accomplished by 'hopping' to different panoramic points. This paper introduces an experimeatal image-based VR system. The techniques utilized in the system, in particular the authoring and interactive control tools of the system, are described in detail.

Preoperative surgical planning and simulation of complex cranial base tumors in virtual reality

The extremely complex anatomic relationships among bone, tumor, blood vessels and cranial nervesremains a big challenge for cranial base tumor surgery. Therefore, a good understanding of the patient specific anatomy and a preoperative planning are helpful and crucial for the neurosurgeons. Three dimensional （3-D） visualization of various imaging techniques have been widely explored to enhance the comprehension of volumetric data for surgical planning.

Virtual reality system for diagnosis and therapeutic planning of cerebral aneurysms

Background The virtual reality （VR） system can provide the neurosurgeon to intuitively interact with and manipulate the three dimensional （3-D） image similarly to manipulate a real object.it was seldom reported that the system was used in diagnosis and treatment of cerebral aneurysms.This study aimed to investigate the application of VR system in diagnosis and therapeutic planning of cerebral aneurysms.Methods A total of 24 cases of cerebral aneurysms were enrolled in this study from 2006 to 2008, which diagnosed by 3-D digital subtraction angiography （3D-DSA） or VR-based computed tomography angiographies （CTA）.The VR system and 3D-DSA system were used to observe and measure aneurysms and the adjacent vessels.The data of observation and measurements were compared between VR image and 3D-DSA image.All the patients underwent surgical plan and simulated neurosurgical procedures in the VR system.Results There were 28 aneurysms detected in VR system and 3D-DSA system.The VR system generated clear and vivid 3-D virtual images which clearly displayed the location and size of the aneurysms and their precise anatomical spatial relations to the parent arteries and skull.The location, size and shape of the aneurysms and their anatomical relationship with the adjacent vessels were similar between 3-D virtual image and 3D-DSA, but the spatial relationship between aneurysms and skull only been displayed by VR system.This VR system also could simulate simple surgical procedures and surgical environments.Conclusions The VR system can provide a highly effective way to provide precise imaging details as same as 3D-DSA system and assist the diagnosis of cerebral aneurysms with virtual 3-D data based on CTA.It significantly enhances the chosen therapeutic strategy of cerebral aneurysms.

New Algorithm for 3D Facial Model Reconstruction and Its Application in Virtual Reality

3D human face model reconstruction is essential to the generation of facial animations that is widely used in the field of virtual reality (VR). The main issues of 3D facial model reconstruction based on images by vision technologies are in twofold: one is to select and match the corresponding features of face from two images with minimal interaction and the other is to generate the realistic-looking human face model. In this paper, a new algorithm for realistic-looking face reconstruction is presented based on stereo vision. Firstly, a pattern is printed and attached to a planar surface for camera calibration, and corners generation and corners matching between two images are performed by integrating modified image pyramid Lucas-Kanade (PLK) algorithm and local adjustment algorithm, and then 3D coordinates of corners are obtained by 3D reconstruction. Individual face model is generated by the deformation of general 3D model and interpolation of the features. Finally, realistic-looking human face model is obtained after texture mapping and eyes modeling. In addition, some application examples in the field of VR are given. Experimental result shows that the proposed algorithm is robust and the 3D model is photo-realistic.

A Virtual Reality Platform for Context-Dependent Cognitive Research in

Animal survival necessitates adaptive behav-iors in volatile environmental contexts.Virtual reality(VR)technology is instrumental to study the neural mechanisms underlying behaviors modulated by environmental con-text by simulating the real world with maximized control of contextual elements.Yet current VR tools for rodents have limited flexibility and performance(e.g.,frame rate)for context-dependent cognitive research.Here,we describe a high-performance VR platform with which to study con-textual behaviors immersed in editable virtual contexts.This platform was assembled from modular hardware and custom-written software with flexibility and upgradability.Using this platform,we trained mice to perform context-dependent cognitive tasks with rules ranging from discrim-ination to delayed-sample-to-match while recording from thousands of hippocampal place cells.By precise manipula-tions of context elements,we found that the context recogni-tion was intact with partial context elements,but impaired by exchanges of context elements.Collectively,our work establishes a configurable VR platform with which to investigate context-dependent cognition with large-scale neural recording.

From Physical Space to Visual Image Space

The theoretical framework of visual simulation in virtual reality is discussed. The new concept of visual image space is supposed. On the basis of visual image space, in visual perceptive sense, VR is considered as a spatial simulation. The objective of the spatial simulation is to transform physical space to visual image space. Last, the prototype system, surveying & mapping virtual Reality (SMVR), is developed, and the space simulation above is realized. By use of SMVR, the real 3D representation, 3D visual analysis, virtual plan and designs can be implemented.

A review on image-based rendering

Image-based rendering is important both in the field of computer graphics and computer vision,and it is also widely used in virtual reality technology.For more than two decades,people have done a lot of work on the research of image-based rendering,and these methods can be divided into two categories according to whether the geometric information of the scene is utilized.According to this classification,we introduce some classical methods and representative methods proposed in recent years.We also compare and analyze the basic principles,advantages and disadvantages of different methods.Finally,some suggestions are given for research directions on image-based rendering techniques in the future.

基于X3D和Panorama的虚拟校园建设

通过对可扩展3D(X3D)和全景图(Panorama)的分析,提出了如何有效利用这两个软件的各自优势,取长补短,共同提高虚拟现实场景的真实效果。最后,应用这些工具综合开发了既能满足建模逼真度又能满足渲染时实行的天津职业大学虚拟校园。

人工智能和虚拟现实技术在提升超声影像教学质量中的作用

随着人工智能(AI)以及虚拟现实(VR)等技术在医学教学领域中的广泛应用,医学教学模式正在发生变化。本研究基于北京大学深圳医院超声影像科的应用场景,介绍了基于AI和VR技术超声影像临床教学平台的研发与应用。该教学平台通过5G网络传输、边缘计算和云端存储,并结合AI算法分析,实现了超声教学数据的实时更新。通过5G、AI和VR等技术的整合应用,超声影像教学质量得到了显著提升。

基于虚拟现实的大视差图像网格优化拼接算法

图像亮度、局部区域信息强度影响图像清晰度,导致图像拼接效果不佳,为提升图像拼接效果,提出一种基于虚拟现实的大视差图像网格优化拼接算法。基于虚拟现实技术建立一个虚拟现实拼接环境,在此环境下开展图像拼接处理,对待拼接图像实施灰度化处理,增强图像局部区域信息强度;基于投影算法建立低密度的网格,并根据待拼接图像的匹配点分布结果建立网格矩阵,结合全局最佳相似变换矩阵实施矩阵加权叠加,对图像重叠区域展开失真校正;使用内容感知算法对图像重叠区域展开感知识别,找出其中的积累最小像素线,实施图像融合处理,通过融合结果完成大视差图像网格优化拼接。实验结果表明,使用该方法开展图像拼接时,图像拼接时间较短,均方根误差较低,拼接效果较好。

Development of Lever Positioning Manipulation (LPM) from the Perspective of Information Interaction

The benefits of Lever Positioning Manipulation (LPM) in the treatment of lumbar disc herniation have been widely recognized. The emergence of virtual reality (VR) technology in the field of medicine and the successful application of augmented reality (AR) technology in the field of surgery have brought new thinking to manipulation researchers on the treatment of lumbar disc herniation (LDH) in the era of artificial intelligence (AI). In this study, the development trend and clinical efficacy of VR technology were discussed from the development process of this technology, and the combination of information interaction technology in the field of chiropractic was found from the existing research approach of lever positioning treatment of LDH, in order to provide a useful reference for researchers.

基于VR一体机的古生物三维虚拟复原软件系统设计

古生物化石复原对于古生物、古地理、古气候等研究具有重大意义,但存在模型复原制作难度大、工艺成本高等问题。本文基于VR一体机硬件平台,利用虚拟现实技术开发了古生物三维虚拟复原软件系统。通过建模软件3DMax联合ZBrush精雕复原实物模型,基于三维引擎Unity3D与SteamVR协同开发了还原度高的三维空间程序,打造了交互物体展示和场景漫游控制相结合的“沉浸式”拟真三维操作环境。经HTCVIVE VR一体机对软件系统测试结果显示,软件运行流畅,具有很强的通用性,模型导入方便,交互功能便于二次开发扩展。

基于BOPPPS教学模式下的虚拟现实技术在医学影像诊断教学中的运用研究

目的探讨基于BOPPPS教学模式下的虚拟现实技术在医学影像诊断教学中的运用及教学效果。方法60名临床医学专业实习学生被随机分为两组,每组30名。研究组采用基于BOPPPS教学模式下运用虚拟技术进行教学,对照组采用多媒体幻灯片的传统教学方法进行教学,比较两组学员的出科考核成绩、满意度等情况。结果研究组出科理论成绩、读片分析成绩、总成绩均高于对照组,差异均有统计学意义(t分别=7.50、16.14、16.55,P均<0.05)。研究组学生在巩固影像学基础知识、阅片思维能力提高、理论与临床同步、增强自我学习能力、对带教老师的满意度等方面的满意度及总满意度均高于对照组,差异均有统计学意义(t分别=14.64、11.40、11.53、11.16、10.52、29.45,P均<0.05)。结论基于BOPPPS教学模式下的虚拟现实技术可提高教学质量和教学效果,为医学影像教学提供了新的教学模式。

虚拟现实技术对脑卒中上肢功能影响的弥散张量成像研究

目的采用弥散张量成像观察虚拟现实技术对脑卒中患者上肢功能的效果。方法2021年9月至2023年3月,选取福州市第二总医院收治的脑卒中患者80例,随机分为对照组(n=40)和试验组(n=40)。两组均行常规康复,试验组增加虚拟现实技术康复,共4周。治疗前、治疗4周和随访4周时,采用Fugl-Meyer评定量表上肢部分(FMA-UE)和上肢动作研究量表(ARAT)进行评定。治疗前、治疗4周时,行弥散张量成像(DTI)扫描,测量病灶侧大脑脚和内囊后肢平均各向异性分数(FA)和相对各向异性(RA)。结果两组各脱落2例。治疗4周和随访4周时,两组FMA-UE和ARAT评分均显著升高(F>2.790,P<0.001),且试验组评分优于对照组(t>2.297,P<0.05)。治疗4周时,两组内囊后肢FA和RA均增高(t>21.013,P<0.001),试验组优于对照组(t>2.006,P<0.05)。两组内囊后肢FA治疗前后差值(ΔFA)与FMA-UE治疗前后差值呈正相关(r>0.362,P<0.05),试验组内囊后肢ΔFA与ARAT治疗前后差值呈正相关(r=0.459,P<0.01)。结论虚拟现实技术可促进脑卒中患者上肢功能改善,可能与内囊后肢传导恢复有关。

低光照环境下全景拍摄系统设计与应用

随着虚拟现实(VR)技术的发展,全景影像制作需求不断提升。针对目前主流全景影像制作方案在低光照环境下存在的问题,本文设计了一套全景拍摄系统,通过全景云台连接四个全画幅相机,有效提升画质,改善图像在拍摄、拼接中的视差现象,完成了从前期拍摄到后期处理的全流程解决方案。本系统易于拆装、方便扩展、便于携带,适用于多种低光照环境下的拍摄场景需求,所制作的全景影像已应用于VR设备及球幕剧场中,使用效果良好。该系统为低光照环境下全景拍摄提供了一种设计思路,具有良好的应用前景。

基于虚拟现实的船舶航行复杂周围环境图像三维仿真

为提升船舶在复杂航行环境中的安全,提出基于虚拟现实的船舶航行复杂周围环境图像三维仿真方法。该方法使用虚拟现实技术中的Vega Prime虚拟现实开发工具,依据海洋、船舶相关数据与图像,使用Crertor工具建立flt静态三维模型库,从该模型库内导出船舶三维模型所需数据后,使用Vega Prime虚拟现实开发工具的LynXPrime图形界面,对船舶航行复杂周围环境的水体、海浪等进行建模并进行纹理制作后,再通过实时驱动、视景仿真驱动以及仿真交互程序运行,实现船舶航行复杂周围环境图像三维仿真模型的交互。实验结果表明,该方法可有效对船舶航行复杂周围环境的洋流流向、流速、海水温度进行三维仿真。同时也可对船舶航行环境内其他船舶进行红外视景可视化,且应用效果较佳。

元宇宙学习空间的未来教育图景及伦理隐忧

元宇宙是互联网的终极形态,也是数字化转型的终极指向。学习空间是学习行为发生和完成的重要外部支持条件。从人类历史上看,学习空间先后经历了前现代社会自然的生活空间到服务于专门教育活动的学校空间的转变,以及工业社会以来封闭的标准化空间到开放的网络空间的转变。当下,元宇宙技术的突破正在颠覆人们对学习空间的传统认知。元宇宙学习空间以高度的空间沉浸感、深度的虚实融合、多元主体间的强交互等特征,从根本上区别于学习空间的诸历史形态。它构建出一个以学习者主动学习为旨趣的开放学习空间,既关注学习者未来心智结构的形成,也关注达成学习者未来心智结构的具体方式。与此同时,元宇宙学习空间作为未来学习空间的新面向,因其技术、理论构想的不成熟性和社会建构的不完善性而面临虚拟与现实之间的道德风险、自我与世界之间的价值冲突以及元宇宙学习空间的技术逻辑所造成的自我关系困境等伦理问题。

三维虚拟现实物体表面图像点云数据提取仿真

三维虚拟物体图像表面提取过程中,受环境光照、噪声等因素的干扰,导致物体提取准确度降低。为解决上述问题,提出一种三维虚拟现实物体表面图像点云数据提取方法。结合半径滤波和DBSAN聚类方法,删除图像点云数据内的噪声。采用八叉树方法划分点云数据空间,将点云包围在不同立方体包围盒中。通过最小二乘二次曲面拟合局部近邻点,获取候选点在拟合曲线的估计法相矢量,同时根据各个点法相矢量和近邻点法相矢量之间的夹角变化,提取三维虚拟现实物体表面图像点云数据。实验结果表明,所提方法可以准确提取点云数据,且提取时间低于0.25s。