高速铁路综合视频监控系统构成及其技术方案分析

随着计算机技术的发展,视频编码技术在视频监控中的作用越来越重要,它对视频监控系统中的图像质量、网络传输带宽、系统间的互联互通、资源共享等很多方面都具有十分重要的作用。文章主要介绍了高速铁路综合视频监控系统总体构成,并对高速铁路综合视频监控系统编码技术方案选择等进行了分析。     

Parallel video servers: a tutorial

In conventional video-on-demand (VoD) systems, compressed digital video streams are stored in a video server for delivery to receiver stations over a communication network. This article introduces a framework for the design of parallel video server architectures and addresses three central architectural issues: video distribution architectures, server striping policies, and video delivery protocols     

Stereoscopic video watermarking: a comparative study

Despite the sound theoretical, methodological, and experimental background inherited from 2D video, the stereoscopic video watermarking imposed itself as an open research topic. Paving the way towards practical deployment of such copyright protection mechanisms, the present paper is structured as a comparative study on the main classes of 2D watermarking methods (spread spectrum, side information, hybrid) and on their related optimal stereoscopic insertion domains (view or disparity based). The performances are evaluated in terms of transparency, robustness, and computational cost. First, the watermarked content transparency is assessed by both subjective protocols (according to ITU-R BT 500-12 and BT 1438 recommendations) and objective quality measures (five metrics based on differences between pixels and on correlation). Secondly, the robustness is objectively expressed by means of the watermark detection bit error rate against several classes of attacks, such as linear and nonlinear filtering, compression, and geometric transformations. Thirdly, the computational cost is estimated for each processing step involved in the watermarking chain. All the quantitative results are obtained out of processing two corpora of stereoscopic visual content: (1) the 3DLive corpus, summing up about 2 h of 3D TV content captured by French professionals, and (2) the MPEG 3D video reference corpus, composed of 17 min provided by both academic communities and industrials. It was thus established that for a fixed size of the mark, a hybrid watermark insertion performed into a new disparity map representation is the only solution jointly featuring imperceptibility (according to the subjective tests), robustness against the three classes of attacks, and nonprohibitive computational cost.     

Digital video interfacing: a practical solution

Broadcast video technology has begun to shed its analogue history and take on board the benefits of the digital era. Areas such as digital video recording and processing have been addressed. However, the means of conveying digital video information from one device to another have been cumbersome and expensive. The author describes how these problems have been overcome. It describes the limitations of the current method and provides an overview of a new, serial, interface. Details and benefits of the new interface are given and new integrated circuits to implement the interface are also described. Consideration is given to installation, test and measurement     

BilVideo: a video database management system

The BilVideo video database management system provides integrated support for spatiotemporal and semantic queries for video. A knowledge base, consisting of a fact base and a comprehensive rule set implemented in Prolog, handles spatio-temporal queries. These queries contain any combination of conditions related to direction, topology, 3D relationships, object appearance, trajectory projection, and similarity-based object trajectories. The rules in the knowledge base significantly reduce the number of facts representing the spatio-temporal relations that the system needs to store. A feature database stored in an object-relational database management system handles semantic queries. To respond to user queries containing both spatio-temporal and semantic conditions, a query processor interacts with the knowledge base and object-relational database and integrates the results returned from these two system components. Because of space limitations, we only discuss the Web-based visual query interface and its fact-extractor and video-annotator tools. These tools populate the system's fact base and feature database to support both query types.     

Real-time video effects on a PlayStation2

The Sony PlayStation2 (PS2), with its powerful rendering and vector processing capabilities, built-in MPEG decoder, and large capacity hard disc drive (HDD), possesses fundamental assets that make it an ideal platform for processing video. Research carried out at Sony BPRL, where we have extensive experience of video effects processing, has shown that this inexpensive games console can, in fact, create, in real-time, the type of video effects, some of which normally require investment in dedicated hardware (or endless patience as a PC renders them slowly). The paper gives an introduction to the architecture of the PlayStation2, and how it can be used for processing video efficiently in this way. It also covers the main video effects developed, and how they are implemented. These effects include wipes, 3D linear and nonlinear effects (such as pageturn and ripple), colour effects and 'old film' effects.     

Optical fiber-polymer guide coupling by a tapered graded indexglass guide

A new four layer tapered coupler (FLTC) has been studied and tested, able to transfer light efficiently from a monomode fiber to a polymer film guide by means of an auxiliary graded index glass waveguide. A simple theory has been developed to calculate the maximum efficiency of these structures. Experiments have been performed, at λ=1.321 μm, on several FLTC samples, containing K⁺-Na⁺ ion-exchanged glass waveguides and spin coated poly-3BCMU films. Insertion losses in the range 3-6.5 dB have been measured, depending on the taper configuration. The agreement between theoretical and experimental data is good, provided that a suitable ripple of the taper profile is assumed. The application of the new coupler to future integrated waveguide systems, including passive glass components and polymer based all optical devices, is assessed     

Interactive digital video networks: lessons from a commercialdeployment

Broadband networks are now being used in numerous trials throughout the world to provide interactive video services for residential customers. These trials and small-scale commercial deployments lack novel applications and services that make effective use of network capabilities and attract users to experiment with them. The rapid explosion of the Internet has also played a role in the current lack of interest and investment in broadband video networks. This article examines the lessons learned from the commercial deployment of a switched fiber-coax video dial tone network in Dover Township, New Jersey, USA. Future broadband networks will have to combine the capabilities of video dial tone networks and the Internet at an attractive price. Innovative end-to-end applications that go beyond cable TV and movies on demand are needed to renew commercial interest in residential broadband networks     

Effective communication: tips on technical writing

The impact of a technical article may have as much to do with how well it is presented as with the engineering or scientific significance of the work. A well-written article is easier to understand and easier to remember; the more readers that remember your work, the higher the likelihood it will get cited. This article reviews some basic principles and discusses a few tips (dos and don'ts) about writing technical papers.     

1.17议题的博弈——JTG5-6会议纪实

当前,我国与俄罗斯的关系处于历史最好时期,双方在多个领域实现了战略协作,在无线电管理和无线电频率协调等方面,也进行了友好的合作交流。在JTG5-6会议上,由于IMT业务与其他业务之间的兼容问题,我国的代表与俄罗斯方在此议题上展开了博弈,力争维护我国无线电台（站）的合法权益。     

Ethics and technical communication: a case for foundationalapproaches

The study of ethics is important for technical communication students and professionals because as workers and as citizens they confront ethical dilemmas and must act. The article describes and contrasts several foundational and nonfoundational ethical approaches. Analyzing two well known ethics cases from the perspective of the different approaches, it is argued that although foundational approaches are limited, they provide better insights than do nonfoundational approaches. Finally, the article describes a problem solving technique, based on foundational approaches and communicative ethics, that can be used by technical communication students and professionals to analyze ethical dilemmas     

构建基于云平台的机顶盒视频点播系统

随着数字电视的普及,用户不仅仅希望通过机顶盒看电视节目,他们希望获得更多针对他们小区的个性化定制服务,而服务商也希望可以针对不同小区提供差别化的服务。面对这样的个性化需求,如何架设和配置服务器成了大家首要考虑的问题。利用云平台来搭建基于数字机顶盒的视频点播系统,可以使得服务商最大程度地满足小区用户对视频服务的个性化需求,同时又可以动态地利用和分配网络和服务器资源。     

Making a cost-effective video server

A cost-effective system must allocate video files to the right place at the right time. We present the characteristics of different storage media and provide an analytical model for obtaining the cost of storing video files. We then state the video file allocation problem and provide a solution     

SDI视频四合一图像处理器的设计

介绍了基于SDI标准接口的视频四合一图像处理器的设计思想和总体结构，具体分析了各部分功能。该方案利用SDI串行数字接口信号转变为ITU-R BT656标准的并行视频信号及其反变换等技术，结合VHDL对多个模块内的FPGA进行编程，使处理器实现在同一个显示器上显示4路不同的视频活动图像，提高了操作便利性，节省了大量空间和设备资源。     

会议电视会场系统工程设计概述

结合《会议电视会场系统工程设计规范》GB50635-2010的要求,介绍了会议电视会场系统中音频系统、视频系统、灯光系统和会场环境设计的主要内容,并通过工程实例进一步阐述会场系统的设计方案.     

Error control and concealment for video communication: a review

The problem of error control and concealment in video communication is becoming increasingly important because of the growing interest in video delivery over unreliable channels such as wireless networks and the Internet. This paper reviews the techniques that have been developed for error control and concealment. These techniques are described in three categories according to the roles that the encoder and decoder play in the underlying approaches. Forward error concealment includes methods that add redundancy at the source end to enhance error resilience of the coded bit streams. Error concealment by postprocessing refers to operations at the decoder to recover the damaged areas based on characteristics of image and video signals. Last, interactive error concealment covers techniques that are dependent on a dialogue between the source and destination. Both current research activities and practice in international standards are covered     

主体面部照明的使用技巧

阐明了在电视图像中人物面部的照明的重要性。对面部照明的创造性的使用,可表现出人物的喜、怒、哀、乐,还能塑造人物形象,直接影响到节目的制作质量。介绍了人物面部创造性照明的几种风格：自然风格、真实风格、写实风格和表现风格,并讨论了高调、低调和特殊面部照明的处理。