基于双处理器图像采集与处理的同步

OMAP系列是TI公司针对第三代手机而开发的高性能多媒体处理器，集成有一个ARM的内核和一个DSP的内核(TMS320C55x)。本文设计了OMAPl510和OV7640的接口电路。采用非常简单的机制，实现了ARM处理器采集图像与DSP视频编码的同步，该方案可广泛应用在采用双处理器分别进行图像采集和压缩的硬件平台上。     

VIDOS, a system for video editing and format conversion over the Internet

VIDOS is a Java-based server–client video management system that permits one to customize a personal version of any downloadable digital video file over the Internet or local intranet. It enables one, without purchasing expensive video editing software, to edit the video spatially and temporally, to specify the desired zoom factor, frame rate and video format, and to choose the nature and quality of digital compression before downloading the edited video. VIDOS permits videos to be adapted to suit their end uses. By potentially reducing their size, it can improve corporate and personal efficiency by speeding network transfers and cutting disc storage requirements.     

A scalable signature scheme for video authentication

This paper addresses the problem of ensuring the integrity of a digital video and presents a scalable signature scheme for video authentication based on cryptographic secret sharing. The proposed method detects spatial cropping and temporal jittering in a video, yet is robust against frame dropping in the streaming video scenario. In our scheme, the authentication signature is compact and independent of the size of the video. Given a video, we identify the key frames based on differential energy between the frames. Considering video frames as shares, we compute the corresponding secret at three hierarchical levels. The master secret is used as digital signature to authenticate the video. The proposed signature scheme is scalable to three hierarchical levels of signature computation based on the needs of different scenarios. We provide extensive experimental results to show the utility of our technique in three different scenarios—streaming video, video identification and face tampering.

A window-assisted video partitioning strategy for partitioning and caching video streams in distributed multimedia systems

In this paper, we address the issue of efficiently streaming a set of heterogenous videos under the constraint of service latency over a scalable multimedia systems. We propose a novel strategy, referred to as window-assisted video partitioning (WAVP), for rendering cost-effective multimedia services. The objective is to minimize the service cost and maximize the number of requests that can be successfully served under resources constraints (cache capacity and link bandwidth). We formulate the problem of video partitioning as an optimization of both bandwidth resources and cache space, and derive the optimal schedule window for different video portions under consideration of time constraints, the popularities and the sizes of the video portions. In WAVP, video are partitioned into multiple portions and delivered according to by adaptive schedule windows. We prove that WAVP strategy not only optimize the service cost but also be able to serve requests under the time constraints without causing too much delay. We conduct mathematical analysis and derive certain performance bounds that quantify the overall performance of the strategy. It shows that the service cost can be optimized by adjusting the schedule window and resources utilization can be improved as video streams are partitioned into multiple portions. We evaluate the performance under several influencing parameters such as available bandwidth, cache capacity, and partition gradients. Simulation results show that our proposed method can not only significantly reduce the service cost under tight time constraints and with low partition overhead, but also balance the utilization of network resources to achieve high acceptance ratio with low average service cost.     

Real-time software-based video coder for multimedia communication systems

A novel software-based video compression algorithm, the Popular Video Coder (PVC), is presented in this paper, and a video phone system, the Popular Phone, is also implemented based on the PVC. The PVC simplifies the traditional video coder by removing the transform and the motion estimation parts and modifies the quantizer and entropy coder. Two novel coding algorithms, the adaptive quantizer and the modified windowed Huffman-like coder, are used in the PVC to encode the video data with a quality picture at a high compression ratio. The video quality of the proposed coder is as good as that of the MPEG coder when the input is a low-resolution and slow-motion video, and the computational complexity of the PVC is much lower than that of the Motion Picture Expert Group (MPEG). Since no compression hardware is needed for the PVC to encode and decode video data, the cost and complexity of developing multimedia applications, such as video phone and multimedia e-mail systems, can be greatly reduced. Furthermore, some networking issues, such as error control and flow control, are discussed in connection with applying the PVC to implement the Popular Phone.     

A system framework for open distributed processing

Emerging distributed applications increasingly require adequate tools and techniques for system- and application-level management. The integration of both aspects in an overall system framework is an important issue. This paper presents such a framework supporting advanced distributed applications in the context of the evolving Open Distributed Processing reference model. For system-level communication, an efficient subsystem providing advanced service capabilities is presented to cope with the increasing diversity of application service requirements. For application-level processing, a distributed object-based environment is offered. It implements location-independent invocation and object mobility and provides a high level of distribution transparency. The approach is augmented with tools and techniques for managing an overall application configuration.     

基于FPGA的视频图像采集系统的设计

分析了各种视频采集方案的研究现状.对如何采用CCD摄像头采集高分辨率、高质量的图像以及基于FPGA的嵌入式视频图像采集系统的实现方法进行了研究.采用了以摄像头 解码芯片模式为采集方案,针对视频解码芯片ADV7181B,实现了I2C总线配置、ITU656解码、VGA显示模块的设计.设计的视频采集控制器已经在Altera公司的CycloneⅡ系列FPGA(EP2C35)上实现.结果显示本设计具有速度高、成本低、易于集成等优点.     

The new mexico state university ring-star system: A distributed unix environment

A distributed version of the UNIX operations system is currently under development through a joint effort of New Mexico State University and the Hebrew University of Jerusalem. A microprocessor version of the UNIX kernel has been developed which will run on any PDP-11 or LSI-11 based processing element and allows processes to run in a UNIX ‘look-alike’ environment. Each process is fully transportable among all processors in the system. Although the preliminary version of the system was built in a star configuration, the system is currently being upgraded by the addition of a communication ring with 8-bit microprocessors as ring interface units. The current paper describes the software structure, the hardware structure and the communication protocol of the system.     

A two-level queueing system for interactive browsing and searching of video content

This paper presents a two-level queueing system for dynamic summarization and interactive searching of video content. Video frames enter the queueing system; some insignificant and redundant frames are removed; the remaining frames are pulled out of the system as top-level key frames. Using an energy-minimization method, the first queue removes the video frames that constitute the gradual transitions of video shots. The second queue measures the content similarity of video frames and reduces redundant frames. In the queueing system, all key frames are linked in a directed-graph index structure, allowing video content to be accessed at any level-of-detail. Furthermore, this graph-based index structure enables interactive video content exploration, and the system is able to retrieve the video key frames that complement the video content already viewed by users. Experimental results on four full-length videos show that our queueing system performs much better than two existing methods on video key frame selection at different compression ratios. The evaluation on video content search shows that our interactive system is more effective than other systems on eight video searching tasks. Compared with the regular media player, our system reduces the average content searching time by half.     

Searching and editing MPEG-compressed video in a distributed online environment

WebClip (on-line demo at http://www.ctr.columbia.edu/webclip) is a compressed video searching and editing system operating over the World Wide Web. WebClip uses a distributed client-server model including a server engine for content analysis/editing, and clients for interactive controls of video browsing/editing. It specializes several unique features, including compressed-domain video feature extraction and manipulation, multi-resolution video access, content based video browsing/retrieval, and a distributed network architecture.     

基于非均匀量化的小波域分布式深度图视频编码

针对分布式多视点加深度格式(DMVD)的视频编码中深度图视频解码质量问题,提出一种结合子带层及子带系数的小波域分布式深度视频非均匀量化方案,通过给边缘分配更多比特来提升深度图的边缘质量。结合深度图经小波变换后系数分布特性,对第N层的低频小波系数采用均匀量化方案,对其他层高频小波系数采用非均匀量化方案。针对高频系数的非均匀量化,对处于"0"左右的高频系数采用较大的量化步长,随着高频系数幅度值的增大,量化步长逐渐减小,量化逐渐精细,从而提升深度图中的边缘细节质量。实验结果表明,对于边缘较多且变化较明显的"Dancer"和"PoznanHall2"深度序列,该算法能够有效地提高二者的边缘信息质量从而提高其率失真(R-D)性能,最高可达1.2 dB;而对于边缘区域较小且较为模糊的"Newspaper"和"Balloons"深度序列,系统的R-D性能也能被提升0.3 dB左右。     

Mask-based fingerprinting scheme for digital video broadcasting

In this paper we propose a novel method to achieve video fingerprinting and confidentiality in a broadcasting environment. The fingerprinting technique can be used to generate unique copies for individual subscribers and can be used to identify the copyright violator. Thus for tracing the copyright violator, unique copy per subscriber is needed whereas broadcasting requires a single copy to be transmitted to everyone. The proposed method efficiently incorporates both these requirements. In addition to the fingerprinting requirement to trace the subscriber who is violating the copyright, a confidentiality requirement needs to be implemented against the non-subscribers in the broadcast region. The proposed algorithm efficiently combines both the fingerprinting requirement and confidentiality requirement into one single atomic process. The proposed algorithm uses robust invisible watermarking technique for fingerprinting and masking technique for confidentiality. The additional advantage of the proposed scheme is that it also supports MPEG-2 compressed domain processing, which is useful for many broadcasting standards.     

DeViouS: A distributed environment for computer vision

Computer vision, owing to the size and complexity of its tasks and its importance to industrial and economic growth, was selected as one of the grand challenge problems by the U.S. Federal High Performance Computing Program. Integration of vision operations is identified as a key element of the challenge. A system to integrate computer vision in a distributed environment is presented here. This system, called DeViouS, is based on the client/server model and runs in a heterogeneous environment of Unix workstations. Modern computing environments include large numbers of high-powered workstations connected by a very fast network. Many of these computers are idle most of the time. DeViouS takes advantage of this feature of computing environments to distribute the execution of vision tasks. Two primary goals of DeViouS are to provide a practical distributed system and a research environment for vision computing. DeViouS is based on a modular design that allows experimentation in various aspects of algorithm design, scheduling and network programming. It can make use of any existing computer vision packages with very minor changes to DeViouS. DeViouS has been tested in an environment of SUN and Digital workstations and has shown substantial improvements in speed over sequential computing with negligible overhead.     

A distributed platform for personalized advertising in digital interactive TV environments

Advertising plays an important role in modern free markets. Furthermore, advertising is moving towards the establishment of one-to-one marketing relationships. Thus, personalized advertisement is currently considered as a hot topic in product promotion as it can be proved beneficial for all the key players, such as the advertisers, the advertised companies, as well as the consumers. Interactive TV and WWW can provide the means for personalized advertising. But of course, special systems and platforms for personalization must be first developed. This paper proposes a prototype system which efficiently achieves the personalization of the advertisements in the environment of digital interactive TV. Thus, the environment for the exploitation of the proposed system are examined, the details in design and implementation are given, while extensive operation testing and evaluation are provided proving its high applicability in real business environments.     

KAIST image computing system (KICS): A parallel architecture for real-time multimedia data processing

An efficient parallel architecture is proposed for high-performance multimedia data processing using multiple multimedia video processors (MVP; TMS320C80), which are fully programmable general digital signal processors (DSP). This paper describes several requirements for a multimedia data processing system and the system architecture of an image computing system called the KAIST Image Computing System (KICS). The performance of the KICS is evaluated in terms of its I/O bandwidth and the execution time for some image processing functions. An application of the KICS to the real-time Moving Picture Expert Group 2 (MPEG-2) encoder is introduced. The programmability and the high-speed data-access capability of the KICS are its most important features as a high-performance system for real-time multimedia data processing.     

基于depth-map和分布式视频编码的多视点视频传输方法

针对多视点视频传输系统数据量庞大的问题,提出一种基于深度图(depth-map)和分布式视频编码(DVC)的不等错误保护(UEP)传输方法。该方法首先基于多个视点提取深度图;然后,在传输过程中传输一个视点及其深度图;最后,经过网络传输,在解码端由一个视点图及其深度图生成其他视点。由于视点图和深度图在解码端的重要程度不同,对需要传输的视点图和深度图采用不同的分布式视频编码方法,进行不平等的错误保护。仿真实验结果表明,所提传输方法比传统的分布式多视点视频编码传输系统具有更好的抗误码性能,提高了传输可靠性,图像的峰值信噪比(PSNR)约提高1.5dB。     

Integrating semantic analysis and scalable video coding for efficient content-based adaptation

Scalable video coding has become a key technology to deploy systems where the adaptation of content to diverse constrained usage environments (such as PDAs, mobile phones and networks) is carried out in a simple and efficient way. Content-based adaptation and summarization are fields that aim for providing improved adaptation to the user, trying to optimize the semantic coverage in the adapted/summarized version. This paper proposes the integration of content analysis with scalable video adaptation paradigm. They must be fitted in such a way that the efficiency of scalable adaptation is not damaged. An integrated framework is proposed for semantic video adaptation, as well as an adaptive skimming scheme that can use the results of semantic analysis. They are described using the MPEG-21 DIA tools to provide the adaptation in a standard framework. Particularly, the case of activity analysis is described to illustrate the integration of semantic analysis in the framework, and its use for online content summarization and adaptation. Overall efficiency is achieved by means of computing activity using compressed domain analysis with several metrics evaluated as measures of activity. Work supported by the Ministerio de Ciencia y Tecnología of the Spanish Government under project TIN2004-07860 (MEDUSA) and by the Comunidad de Madrid under project S-0505-TIC-0223 (PROMULTIDIS).     

基于DM642的视频采集与传输系统设计

本文应用TI公司的TMS320DM642为核心处理器设计实时的视频采集与传输系统,以摄像头为模拟视频信号采集输入,采用TVP5150和飞利浦的SAA7121H芯片进行A/D和D/A转换,利用EDMA实现对数字视频数据的搬运,利用DM642的视频口来控制输入和输出,从而完成视频采集、数字化处理、传输和显示的系统功能。基于DSP嵌入式芯片的特点,系统具有丰富的外设接口和高度的可编程性,从而具有较好的灵活性和扩展性,以便应用在不同的环境下。     

A flexible communications protocol for a distributed surveillance system

On-line surveillance for safety and security is a major requirement of public transport and other public places to address the modern demands of mobility in major urban areas and to effect improvements in quality of life and environment protection. The surveillance task is a complex one involving technology, management procedures and people. Visual surveillance based on Closed Circuit Television system is an important part of such systems, but visual processing is not sufficient and the geographical distribution of devices and management has to be taken into account. In this paper we present a surveillance architecture that reflects the distributed nature of the monitoring task and allows for distributed detection processes, not only dealing with visual processing but also with devices such as acoustic signature detection and mobile smart cards, actuators and a range of other possible sensors. The design uses ideas from control engineering and distributed communications networks resulting in a communications architecture based on CORBA and XML messaging. We have shown how to define a generic device/sensor model appropriate for the surveillance task and sufficiently flexible so as to allow for scalability, expansion and customisation of a practical surveillance task. The paper gives sufficient details on the protocols to show how intelligent detection modules can be integrated as part of this kind of system. The system components have been implemented and integrated in two major successful trials in metropolitan railway stations in London and in Paris, as part of a major EU-funded project (PRISMATICA).