A student's perspective: getting real with virtual reality

As with many up and coming technologies, the road to wide acceptance is not always smooth. Virtual reality (VR) is one such technology whose bumpy ascent is well underway. VR is not all that new but the steady price/performance gains for computational power have helped it gain a broader base of applications and even a little popularity along the way. The author's current research is one example of how VR can be used as an analysis as well as a visualization tool. He is developing interactive scenarios where the user can pose "what if?" questions in a VR environment and the VR environment will respond with an array of possibilities. The user will then be able to experience and better assess the impacts of each alternative. The interactive aspects of VR make it an ideal platform for developing scenarios across a broad range of applications.     

虚拟现实技术及其发展战略

虚拟现实是一门实现人和计算机之间直观自然交互的新技术，它对于极大地推广计算机的普及和应用具有不可估量的作用，本文先给出虚拟现实的概念及其特点，然后分析了它的发展状况，存在的问题以及研究的关键技术，在对虚拟现实技术的应用前景进行了综述之后重点对我国虚拟现实技术的研究和应用的发展战略提出了自己的建议。     

Analysis of end-to-end QoS for networked virtual reality services in UMTS

Virtual reality services may be considered a good representative of advanced services in the new-generation network. The focus of this article is to address quality of service support for VR services in the context of the UMTS QoS framework specified by the 3G standardization forum, the Third Generation Partnership Project. We propose a classification of VR services based on delivery requirements (real-time or non-real-time) and degree of interactivity that maps to existing UMTS QoS classes and service attributes. The mapping is based on matching VR service requirements to performance parameters and target values defined for UMTS applications. Test cases involving heterogeneous VR applications are defined, using as a reference a general model for VR service design and delivery. Measurements of network parameters serve to determine the end-to-end QoS requirements of the considered applications, which are in turn mapped to proposed VR service classes.     

Virtual surgery in a (tele-)radiology framework

Presents telemedicine as an extension of a teleradiology framework through tools for virtual surgery. To classify the described methods and applications, the research field of virtual reality (VR) is broadly reviewed. Differences with respect to technical equipment, methodological requirements and areas of application are pointed out. VR, desktop VR and augmented reality are differentiated and discussed in some typical contexts of diagnostic support, surgical planning, therapeutic procedures, simulation and training. Visualization techniques are compared as a prerequisite for VR and assigned to distinct levels of immersion. The advantage of a hybrid visualization kernel is emphasized with respect to the desktop VR applications that are subsequently shown. Moreover, software design aspects are considered by outlining functional openness in the architecture of the host system. A teleradiology workstation was extended by dedicated tools for surgical planning through a plug-in mechanism. Examples of recent areas of application are introduced, such as liver tumor resection planning, diagnostic support in heart surgery, and craniofacial surgery planning. In the future, surgical planning systems will become more important. They will benefit from improvements in image acquisition and communication, new image processing approaches and techniques for data presentation. This will facilitate pre-operative planning and intra-operative applications     

Voltage Regulator Optimization Using Multiwinding Coupled Inductors and Extended Duty Ratio Mechanisms

This paper examines design optimization of voltage regulators (VRs) for microprocessor applications. Optimality of competing VR topologies, such as conventional (Conv) buck, coupled inductor, and extended duty ratio converters, is examined using efficiency norms and a new cost-per-watt metric to compare the amount of output capacitance (which is strongly correlated to the VR cost) to the efficiency. Coupled inductors provide a higher steady-state inductance than transient inductance. Lower transient inductance allows for smaller output capacitance. However, lower output capacitance requires a higher switching frequency and thus yields greater switching losses and lower efficiency. Extended duty ratio mechanisms reduce the switching voltage, and hence, reduce switching losses and increase efficiency. Experimental data are provided that the coupled inductor extended duty ratio converter has the same average efficiency, has higher light-load efficiency, and uses one-third of the output capacitance as the Conv multiphase buck converter. Hence, the combination of multiwinding coupled inductors and extended duty ratio mechanisms is shown to be the optimal VR configuration. The optimality concepts contributed in this paper resolve the ambiguity between VR cost and efficiency, and are essential for selecting the best solution among several competing VR designs.      

基于三维重建的虚拟现实类鸟飞行系统

随着虚拟现实(virtual reality, VR)技术的飞速发展,各种应用层出不穷。然而目前大多应用仅限于定点的静态全景展示及游览,无法利用VR化不可能为可能的优越性。本文提出了一种融合VR技术与三维重建算法的类鸟飞行交互模拟系统。该系统搭建了结构稳定的硬件控制平台用以改变实际姿态,同时通过软件仿真了虚拟环境中鸟类的飞行,结合硬件驱动及软件模拟实现了深层次的飞行模拟。现有的虚拟环境大多通过人工建模、激光扫描仪或无人机(unmanned aerial vehicle, UAV)航拍构造,其中建模存在费时费力的缺点,激光扫描仪则无法适应大规模重建,而UAV成本高昂且需专业培训。本文引入了基于图像分簇的PMVS (patch based multi-view stereopesis)算法,只需输入特定场景的图片即可利用计算机自动恢复出三维结构,不仅快速而且可对任意场景重构。使用户在足不出户的情况下即可在世界各地体验飞行,为旅游事业及VR产业提供了一种新的可能。     

5G网络中的移动VR应用

首先介绍移动VR/AR/MR的应用场景、系统的基本原理,分析其对网络的要求,指出现有移动网络承载移动VR/AR/MR应用的问题;结合5G网络中引入的新架构和新技术,提出移动VR网络解决方案,进一步分析该解决方案带来的对应用使能的增强效果,旨在为 5G 网络中的移动 VR 应用提供参考,起到推动5G生态圈应用发展的示范效果。     

虚拟现实技术在医学领域的研究现状与进展

虚拟现实(VR)与其所衍生的增强现实(AR)和混合现实(MR)能把携带三维信息的虚拟场景与真实世界相互叠加,极大地提升用户感官世界的直观性、精准性、实时性。该技术的推广与应用,将会给医学领域带来变革式发展。本文剖析VR/AR/MR的概念并简述其发展历程,分别对虚拟现实和增强现实在医学领域的应用进行阐述,并通过微软产品HoloLens的特点分析基于混合现实的解决方案在医学领域的优势。最后对VR/AR/MR目前在医学领域所存在的不足进行归纳,并对未来的发展趋势进行展望。     

Skin Electronics: Next-Generation Device Platform for Virtual and Augmented Reality

Virtual reality (VR) and augmented reality (AR) are overcoming the physical limits of real-life using advances in devices and software. In particular, the recent restrictions in transportation from the coronavirus disease 2019 (COVID-19) pandemic are making people more interested in these virtual experiences. However, to minimize the differences between artificial and natural perception, more human-interactive and human-like devices are necessary. The skin is the largest organ of the human body and interacts with the environment as the site of interfacing and sensing. Recent progress in skin electronics has enabled the use of the skin as the mounting object of functional devices and the signal pathway bridging humans and computers, with opening its potential in future VR and AR applications. In this review, the current skin electronics are summarized as one of the most promising device solutions for future VR/AR devices, especially focusing on the recent materials and structures. After defining and explaining VR/AR systems and the components, the advantages of skin electronics for VR/AR applications are emphasized. Next, the detailed functionalities of skin electronic devices, including the input, output, energy devices, and integrated systems, are reviewed for future VR/AR applications.     

Wireless User Perspectives in Europe: HandSmart Mediaphone Interface

HandSmart is one example of wearable device that can be used as a user interface for advanced mediaphones and it is based on MARISIL a Mobile Augmented Reality Interface Sign Interpretation Language. This paper will describe the interface and some of the applications of these new types of personal devices. The user-centered development methodology is discussed in brief at the end of the paper. Evolutions in technology have provided a variety of new opportunities for exploring and discovering virtual 3D worlds. Head-mounted displays and data gloves enable us to interact and immerse much better into the artificial generated 3D environment. Such devices have been advertised in the entertainment media and are recognized by the public as the symbols of virtual reality (VR). Augmented Reality that has the attribute of being more related to real world than VR by overlaying virtual sounds, feelings or visions onto our senses within the real world, can therefore extend our natural experiences. The authors believe that the new generation of mediaphones can embed these new techniques.     

Emerging trends in virtual heritage

From the pyramids at Giza to Kakadu National Park in Australia, the world's cultural and natural heritage has stood the test of time. The pace of progress threatens these landmarks of our past at an ever-increasing pace. Rapid advances in digital technologies in recent years, from new media to virtual reality (VR) and high-speed networks, have offered heritage some hope. The first wave of VR worlds failed to live up to the promise. Today, the forward march of technology has quietly enabled a second wave of VR applications. Digital tools and techniques offer new hope to the often painstakingly complex tasks of archaeology, surveying, historic research, conservation, and education. These emerging second-generation technologies can be grouped into three domains: 3D documentation (everything from site surveys to epigraphy), 3D representation (from historic reconstruction to visualization), and 3D dissemination (from immersive networked worlds to “in situ” augmented reality). The author reviews these emerging trends     

Recent Advances and Opportunities of Active Materials for Haptic Technologies in Virtual and Augmented Reality

Virtual reality and augmented reality (VR/AR) are evolving. The market demands and innovation efforts call for a shift in the key VR/AR technologies and engaging people virtually. Tele-haptics with multimodal and bilateral interactions are emerging as the future of the VR/AR industry. By transmitting and receiving haptic sensations wirelessly, tele-haptics allow human-to-human interactions beyond the traditional VR/AR interactions. The core technologies for tele-haptics include multimodal tactile sensing and feedback based on highly advanced sensors and actuators. Recent developments of haptic innovations based on active materials show that active materials can significantly contribute to addressing the needs and challenges for the current and future VR/AR technologies. Thus, this paper intends to review the current status and opportunities of active material-based haptic technology with a focus on VR/AR applications. It first provides an overview of the current VR/AR applications of active materials for haptic sensing and actuation. It then highlights the state-of-the-art haptic interfaces that are relevant to the materials with an aim to provide perspectives on the role of active materials and their potential integration in haptic devices. This paper concludes with the perspective and outlook of immersive multimodal tele-haptic interaction technologies.     

面向VR应用的花卉植物物理渲染技术研究与实现

花卉植物高真实感的仿真交互是目前虚拟植物可视化研究的一个重要方向。随着虚拟现实技术的普及,越来越多的应用采用了VR头戴设备的呈现方式。VR系统需要高度真实的沉浸感画面,通用的植物建模和图形引擎渲染功能已不能满足该需求。该文通过分析光照原理并融合基于物理的渲染技术,提出基于双向散射分布函数BSDF的花卉植物高度真实感的物理渲染算法,利用ShaderLab,对几种盆栽花卉植物在光照下进行仿真,并对融合算法做优化处理。针对VR头盔设备HTC Vive的成像效果,对图像进行扭曲变形优化,使画面更符合人眼双目立体视觉成像效果,增强系统沉浸感。最后基于该方法设计并实现了一个头盔式VR花卉植物仿真模拟系统,获得了逼真的场景漫游体验效果。     

Bandwidth Improvements for Peak-Current Controlled Voltage Regulators

To ensure the current sharing among the interleaved phases, the peak-current control is widely used in the voltage regulator (VR) applications. Meanwhile, to save the cost and footprint by reducing the output capacitance, high control bandwidths are mandatory. Because of the sample-hold effect in the peak-current loop, there exist stringent challenges to the high-bandwidth designs for VRs. In this paper, the influence from the sample-hold effect is investigated to clarify the difference between the VR and conventional applications. After that, two approaches for higher bandwidth are introduced. To decrease the phase delay due to the sample-hold related double poles, excessive external ramps are inserted to the modulators. To increase the effective sampling frequency, the phase inductor currents are coupled, either by the coupled-inductor structure or through the feedback control. In addition, a small-signal model including the sample-hold effect is derived for the coupled-inductor buck to explain the improvement. High-bandwidth designs are verified by the simulation and experimental results. A bandwidth of one-third switching frequency is demonstrated with a coupled-inductor VR.     

基于未来应用的未来网络固定特征

越来越丰富的网络应用对网络功能和性能提出了更高的要求。车联网需要网络满足低时延和高可靠性要求;远程医疗需要网络有确定性时延和安全保证;工业互联网要求网络满足大连接要求;AR/VR应用要求低时延和高带宽;量子计算也对网络安全等方面提出了新的要求。现有的IP网络由于自身架构的局限性,只提供尽力而为的服务,无法满足未来网络应用需要。调研未来20年内的网络应用,分析未来网络应该具有的功能和性能,通过对车联网、远程医疗、工业物联网、AR/VR和量子计算应用场景的描述,分析满足这些场景分别需要的网络性能,得出未来网络的性能指标。     

Wearable Soft Technologies for Haptic Sensing and Feedback

Virtual reality (VR) and augmented reality (AR) systems have garnered recent widespread attention due to increased accessibility, functionality, and affordability. These systems sense user inputs and typically provide haptic, audio, and visual feedback to blend interactive virtual environments with the real world for an enhanced or simulated reality experience. With applications ranging from immersive entertainment, to teleoperation, to physical therapy, further development of this technology has the potential for impact across multiple disciplines. However, VR/AR devices still face critical challenges that hinder integration into everyday life and additional applications; namely, the rigid and cumbersome form factor of current technology that is incompatible with the dynamic movements and pliable limbs of the human body. Recent advancements in the field of soft materials are uniquely suited to provide solutions to this challenge. Devices fabricated from flexible and elastic bio-compatible materials have significantly greater compatibility with the human body and could lead to a more natural VR/AR experience. This review reports state-of-the-art experimental studies in soft materials for wearable sensing and haptic feedback in VR/AR applications, explores emerging soft technologies for on-body devices, and identifies current challenges and future opportunities toward seamless integration of the virtual and physical world.     

浅谈5G时代新媒体的发展

针对5G时代新媒体的发展，本文结合5G技术的发展现状和试验应用，在综合考虑新媒体特点的基础上，讨论了新媒体在5G时代所面临的机遇和挑战。笔者认为自媒体、VR、物联网新媒体将成为新媒体在5G时代的典型应用，同时海量数据和媒体监管是5G时代新媒体面临的挑战。     

Multidimensional vector radix FHT algorithms

In this paper, efficient multidimensional (M-D) vector radix (VR) decimation-in-frequency and decimation-in-time fast Hartley transform (FHT) algorithms are derived for computing the discrete Hartley transform (DHT) of any dimension using an appropriate index mapping and the Kronecker product. The proposed algorithms are more effective and highly suitable for hardware and software implementations compared to all existing M-D FHT algorithms that are derived for the computation of the DHT of any dimension. The butterflies of the proposed algorithms are based on simple closed-form expressions that allow easy implementations of these algorithms for any dimension. In addition, the proposed algorithms possess properties such as high regularity, simplicity and in-place computation that are highly desirable for software and hardware implementations, especially for the M-D applications. A close relationship between the M-D VR complex-valued fast Fourier transform algorithms and the proposed M-D VR FHT algorithms is established. This type of relationship is of great significance for software and hardware implementations of the algorithms, since it is shown that because of this relationship and the fact that the DHT is an alternative to the discrete Fourier transform (DFT) for real data, a single module with a little or no modification can be used to carry out the forward and inverse M-D DFTs for real- or complex-valued data and M-D DHTs. Thus, the same module (with a little or no modification) can be used to cover all domains of applications that involve the DFTs or DHTs.     

Modeling and control strategies for a variable reluctancedirect-drive motor

A high-performance ripple-free dynamic torque controller for a variable-reluctance (VR) motor intended for trajectory tracking in robotic applications is designed. A modeling approach that simplifies the design of the controller is investigated. Model structure and parameter estimation techniques are presented. Different approaches to the overall torque controller design problem are discussed, and the solution adopted is illustrated. A cascade controller structure consisting of a feedforward nonlinear torque compensator, cascaded to a nonlinear flux or current closed-loop controller is considered, and optimization techniques are used for its design. Although developed for a specific commercial motor, the proposed modeling and optimization strategies can be used for other VR motors with magnetically decoupled phases, both rotating and linear. Laboratory experiments for model validation and preliminary simulation results of the overall torque control system are presented     

Conducting a virtual orchestra

The virtual orchestra is a multimodal system architecture based on complex 3D sound environment processing and a compact user interface. The system architecture supports high-performance sound content for VR (virtual reality) applications, and the user controls the performance with a magnetically tracked handheld device. The objective of this work is to give music amateurs the opportunity to conduct a group of musicians and produce a new kind of multimedia experience. To explore this idea, the authors developed a semi-immersive virtual reality system, based on a large projection screen, designed to create an entertaining multimedia experience for nonexpert users. They decided to implement a music performance simulator, a VR system where several virtual characters play different musical instruments and adapt their performance according to the user's instructions.