由抖动图象序列建立自然环境三维真实感全景模型

由真实环境中的现场图象进行三维环境建模是目前国际上研究的热点问题。本文依据合理的运动模型，提出和实现了由包含抖动的摄像机运动下的图象序列建立３Ｄ环境全景模型的两步法。首先通过运动滤波和运动分解获得运动稳定的图象序列，然后采用无特征提取的时空纹理方向精确估计、深度边界确定和遮挡恢复算法，建立全局自然景物的真实感三维环境模型。提出了２种三维全景图象的表示方法，即非阵列方式深度分层区域表示和阵列方式的深度分层布景表示，可用于机器人全局定位的自然路标提取和真实环境虚拟再现的图象合成。该研究推广和结合了外极面图象的方法和全景图象的方法，放宽了对运动的要求，从而可使该种方法适用于室外颠簸的道路环境。和现有运动分层方法相比，避免了该类方法迭代过程中的局部最小化问题，并具有计算和存储效率高，适应性强，算法鲁棒性好的优点。     

一种基于模型方法的三维数字影像生成系统

虚拟现实（ＶＲ）已成为计算机图形学中的一个重要分支,它作为一种新兴媒体,从八十年代末开始受到普遍关注,并已在多个领域发挥出色。本文主要介绍一种基于模型的３Ｄ数字影像生成系统。通过多路摄像机记录真实世界中的人物或情景,并提取数字信息,结合标准的计算机图形方法重现原始的三维景物。     

4D video textures for interactive character appearance

4D Video Textures (4DVT) introduce a novel representation for rendering video‐realistic interactive character animation from a database of 4D actor performance captured in a multiple camera studio. 4D performance capture reconstructs dynamic shape and appearance over time but is limited to free‐viewpoint video replay of the same motion. Interactive animation from 4D performance capture has so far been limited to surface shape only. 4DVT is the final piece in the puzzle enabling video‐realistic interactive animation through two contributions: a layered view‐dependent texture map representation which supports efficient storage, transmission and rendering from multiple view video capture; and a rendering approach that combines multiple 4DVT sequences in a parametric motion space, maintaining video quality rendering of dynamic surface appearance whilst allowing high‐level interactive control of character motion and viewpoint. 4DVT is demonstrated for multiple characters and evaluated both quantitatively and through a user‐study which confirms that the visual quality of captured video is maintained. The 4DVT representation achieves >90% reduction in size and halves the rendering cost.     

三维场景建模的全景外极面图像分析方法

文章提出由非精确摄像机运动下的图像序列建立3D环境模型的全景外极面图像方法,实现了 无特征提取的时空纹理方向精确估计、深度边界确定和遮挡恢复算法.该方法推广并结合了 外极面图像方法和全景图像方法,避免了现有运动分层方法迭代过程中的局部最小化问题,具 有计算和存储效率高、适应性强、算法鲁棒性好的优点.建立的自然景物的真实感三维环境 模型,可用于机器人全局定位的自然路标提取和真实环境虚拟再现的图像合成.     

Autonomic Performance and Power Control on Virtualized Servers: Survey,Practices, and Trends

Modern datacenter servers hosting popular Internet services face significant and multi-facet challenges in performance and power control. The user-perceived performance is the result of a complex interaction of complex workloads in a very complex underlying system. Highly dynamic and bursty workloads of Internet services fluctuate over multiple time scales, which has a significant impact on processing and power demands of datacenter servers. High-density servers apply virtualization technology for capacity planning and system manageability. Such virtuMized computer systems are increasingly large and complex. This paper surveys representative approaches to autonomic performance and power control on virtualized servers, which control the quality of service provided by virtualized resources, improve the energy efficiency of the underlying system, and reduce the burden of complex system management from human operators. It then presents three designed self-adaptive resource management techniques based on machine learning and control for percentile-based response time assurance, non-intrusive energy-efficient performance isolation, and joint performance and power guarantee on virtualized servers. The techniques were implemented and evaluated in a testbed of virtualized servers hosting benchmark applications. Finally, two research trends are identified and discussed for sustainable cloud computing in green datacenters.     

三维动漫制作与虚拟现实结合技术研究

基于为高校三维动漫教学提供良好的教学技术和实验平台,研究了三维动漫制作与虚拟现实技术相结合的方法,采用三维计算机图形技术CG(Computer Graphics)、影像技术和运动捕捉系统,实现高质量高效率的三维动漫制作。介绍了将动漫技术、虚拟现实VR(Virtual Reality)设备和网络技术相整合的交互动漫虚拟环境建设方案。     

Multi-tier service differentiation by coordinated learning-based resource provisioning and admission control

Multiple Internet applications are often hosted in one datacenter, sharing underlying virtualized server resources. It is important to provide differentiated treatment to co-hosted applications and to improve overall system performance by efficient use of shared resources. Challenges arise due to multi-tier service architecture, virtualized server infrastructure, and highly dynamic and bursty workloads. We propose a coordinated admission control and adaptive resource provisioning approach for multi-tier service differentiation and performance improvement in a shared virtualized platform. We develop new model-independent reinforcement learning based techniques for virtual machine (VM) auto-configuration and session based admission control. Adaptive VM auto-configuration provides proportional service differentiation between co-located applications and improves application response time simultaneously. Admission control improves session throughput of the applications and minimizes resource wastage due to aborted sessions. A shared reward actualizes coordination between the two learning modules. For system agility and scalability, we integrate the reinforcement learning approach with cascade neural networks. We have implemented the integrated approach in a virtualized blade server system hosting RUBiS benchmark applications. Experimental results demonstrate that the new approach meets differentiation targets accurately and achieves performance improvement of applications at the same time. It reacts to dynamic and bursty workloads in an agile and scalable manner.     

面向应用服务级目标的虚拟化资源管理

在虚拟环境中实现应用服务级目标,是当前数据中心系统管理的关键问题之一.解决该问题有两个方面的要求:一方面,在虚拟化层次和范围内,能够动态和分布式地按需调整虚拟机资源分配;另一方面,在虚拟化范围之外,能够控制由于虚拟机对非虚拟化资源的竞争所导致的性能干扰,实现虚拟机性能隔离.然而,已有工作不适用于虚拟化数据中心场景.提出一种面向应用服务级目标的虚拟化资源管理方法.首先,该方法基于反馈控制理论,通过动态调整虚拟机资源分配来实现每个应用的服务器目标;同时,还设计了一个两层结构的自适应机制,使得应用模型能够动态地捕捉虚拟机资源分配与应用性能的时变非线性关系;最后,该方法通过仲裁不同应用的资源分配请求来控制虚拟机在非虚拟化资源上的竞争干扰.实验在基于Xen的机群环境中检验了该方法在RUBiS系统和TPC-W基准上的效果.实验结果显示,该方法的应用服务级目标实现率比两种对比方法平均高29.2%,而应用服务级目标平均偏离率比它们平均低50.1%.另一方面,当RUBiS系统和TPC-W基准竞争非虚拟化的磁盘I/O资源时,该方法通过抑制TPC-W基准28.7%的处理器资源需求来优先满足RUBiS系统的磁盘I/O需求.     

Multi‐view reconstruction of dynamic real‐world objects and their integration in augmented and virtual reality applications

We present a flexible system for high‐quality three‐dimensional reconstruction of dynamic real‐world objects based on a modular multi‐camera capture setup. The proposed algorithmic pipeline aims at the acquisition and digitization of natural and realistic representations of real people that can be easily integrated into augmented and virtual reality applications. In this context, we discuss the reduction of mesh complexity as one of the key challenges for visualizing reconstructed three‐dimensional content with augmented and virtual reality glasses and demonstrate different fields of application.     

基于视觉增强现实系统的设计与实现

针对目前增强现实领域尚少有人涉足的运动跟踪注册问题,提出了采用四个彩色标志点的光流场估计运动参数,结合刚体的运动特性以及投影透射模型确定运动物体与摄像机间相对位姿的算法。并把该算法用于以光学透射式头盔显示器为主的增强现实系统中。该系统结构简单、轻便、实用性强、易于实现。一般情况下只需四个平面标志物就可实现运动物体的三维跟踪注册;工作范围大,甚至可以应用到室外的增强现实系统中;数值求解过程是线性过程,误差小,可以满足增强现实系统高精度三维注册的要求。     

可信服务链安全架构研究

针对网络功能虚拟化中服务链的安全性问题,提出一种基于可信计算的安全服务链架构。首先,基于可信计算为网络功能虚拟化架构设置可信管理中心模块,为虚拟网络功能实例的生成、服务链的生成和调整提供可信认证;然后,针对服务链的生成和调整设计了相关安全协议;最后,将HOTP协议引入模型之中,实现了服务链各实例之间的安全认证与安全传输,并支持服务链节点的动态扩充和调整。经过架构仿真分析表明,本安全架构在保证服务链动态性的同时提高了安全性。     

基于服务网格的制造资源集成

提出了一种基于服务网格的制造资源集成方法，通过将服务网格技术引入制造行业，实现了制造资源的虚拟化，为制造资源提供了统一的接口和互操作协议、屏蔽平台及所使用技术的异构性。平台采用基于服务的协同工作流技术，在动态变化的环境中，能够根据用户需求优化业务逻辑及其执行过程，选择、配置和调度相应的制造资源完成指定的任务，实现跨组织的资源共享和任务协同。     

基于OpenGL ES的地形三维显示技术研究

在分析嵌入式可视化基本概念基础上,提出一种基于正方形的社区裁剪方法,结合OpenGL ES图形库,以EVC++4.0为应用程序开发平台模拟三维地形显示,实现地形三维显示的快速建模以及动态显示,同时通过漫游功能、纹理映射和立方体天空盒增强地形的三维真实感.     

Virtualized Traffic: reconstructing traffic flows from discrete spatiotemporal data

We present a novel concept, Virtualized Traffic, to reconstruct and visualize continuous traffic flows from discrete spatiotemporal data provided by traffic sensors or generated artificially to enhance a sense of immersion in a dynamic virtual world. Given the positions of each car at two recorded locations on a highway and the corresponding time instances, our approach can reconstruct the traffic flows (i.e., the dynamic motions of multiple cars over time) between the two locations along the highway for immersive visualization of virtual cities or other environments. Our algorithm is applicable to high-density traffic on highways with an arbitrary number of lanes and takes into account the geometric, kinematic, and dynamic constraints on the cars. Our method reconstructs the car motion that automatically minimizes the number of lane changes, respects safety distance to other cars, and computes the acceleration necessary to obtain a smooth traffic flow subject to the given constraints. Furthermore, our framework can process a continuous stream of input data in real time, enabling the users to view virtualized traffic events in a virtual world as they occur. We demonstrate our reconstruction technique with both synthetic and real-world input.     

Real-time recovery of moving 3D faces for emerging applications

Existing face imaging systems are not suitable to meet the face representation and recognition demands for emerging applications in areas such as interactive gaming, enhanced learning environments and directed advertising. This is mainly due to the poor capture and characterisation of facial data that compromises their spatial and temporal precision. For emerging applications it is not only necessary to have a high level of precision for the representation of facial data, but also to characterise dynamic faces as naturally as possible and in a timely manner. This study proposes a new framework for capturing and recovering dynamic facial information in real-time at significantly high order of spatial and temporal accuracy to capture and model subtle facial changes for enhanced realism in 3D face visualisation and higher precision for face recognition applications. We also present a novel, fast, and robust correspondence mapping approach for 3D registration of moving 3D faces.     

Real-time 3D human capture system for mixed-reality art and entertainment

A real-time system for capturing humans in 3D and placing them into a mixed reality environment is presented in this paper. Nine cameras surrounding her capture the subject. Looking through a head-mounted-display with a camera in front pointing at a marker, the user can see the 3D image of this subject overlaid onto a mixed reality scene. The 3D images of the subject viewed from this viewpoint are constructed using a robust and fast shape-from-silhouette algorithm. The paper also presents several techniques to produce good quality and speed up the whole system. The frame rate of our system is around 25 fps using only standard Intel processor-based personal computers. Besides a remote live 3D conferencing and collaborating system, we also describe an application of the system in art and entertainment, named Magic Land, which is a mixed reality environment where captured avatars of human and 3D computer generated virtual animations can form an interactive story and play with each other. This system demonstrates many technologies in human computer interaction: mixed reality, tangible interaction, and 3D communication. The result of the user study not only emphasizes the benefits, but also addresses some issues of these technologies.     

基于增强现实技术的校园智能应用系统宣传片的制作

产品宣传是关系产品销量的重要环节,在产品的市场推广中起着重要的作用,而增强现实能够增加人们对现实事物的了解。因此,将增强现实技术应用于“校园智能应用系统”概念宣传片中,通过对二维界面、三维物体动态设计、增强现实效果的实景拍摄技巧和视频合成技术的研究,最终制作出一个数字化、智能化的校园环境的“校园智能应用系统”概念产品宣传片,为今后产品宣传片制作和未来校园生活设计构想奠定一定基础。     

A simple approach for point-based object capturing and rendering

Point-based object representations are a powerful alternative to traditional polygonal object representations. Capturing 3D geometry is a mission-critical content acquisition technique in application domains such as virtual reality, CAD/CAM, and physical asset management. We describe SPOC, a simple, point-based object capturing system we've developed to automatically capture and process 3D geometry for point-based image rendering. We also identify the problems involved and describe the technical solutions we've implemented. Finally, we address several algorithmic issues in capturing point models using a simple digital camera and turntable setup, and in processing and rendering point clouds.     

Temporal Reasoning and Bayesian Networks

This work examines important issues in probabilistic temporal representation and reasoning using Bayesian networks (also known as belief networks). The representation proposed here utilizes temporal (or dynamic) probabilities to represent facts, events, and the effects of events. The architecture of a belief network may change with time to indicate a different causal context. Probability variations with time capture temporal properties such as persistence and causation. They also capture event interaction, and when the interaction between events follows known models such as the competing risks model, the additive model, or the dominating event model, the net effect of many interacting events on the temporal probabilities can be calculated efficiently. This representation of reasoning also exploits the notion of temporal degeneration of relevance due to information obsolescence to improve the efficiency.