MPEG-4的3D人体动画框架

3D人体的编码与传输成为近年来人们研究的热点，通常的方法是在MPEG-4框架下定义人体对象。用体对象参数BDP进行描述。本在基于人体解剖学的分层模型基础上，介绍了SMS模型，定义了骨骼、肌肉和模型的节点域及各层的定义参数，所描述的动画更能体现人体的生理特征。     

MPEG-4概述

从ISO/IEC14496的第一部分MPEG-4系统的体系结构出发,分别对MPEG-4标准中提供的主要工具进行了技术描述,包括对象描述框架、系统解码器模型(SDM)和传输多媒体集成框架(DMIF)、场景的二进制描述(BIFS)、同步层、视频对象和音频对象编码等.最后对MPEG-4系统的特性做出了小结并探讨了该标准的应用前景.     

Point-sampled 3D video of real-world scenes

This paper presents a point-sampled approach for capturing 3D video footage and subsequent re-rendering of real-world scenes. The acquisition system is composed of multiple sparsely placed 3D video bricks. The bricks contain a low-cost projector, two grayscale cameras and a high-resolution color camera. To improve on depth calculation we rely on structured light patterns. Texture images and pattern-augmented views of the scene are acquired simultaneously by time multiplexed projections of complementary patterns and synchronized camera exposures. High-resolution depth maps are extracted using depth-from-stereo algorithms performed on the acquired pattern images. The surface samples corresponding to the depth values are merged into a view-independent, point-based 3D data structure. This representation allows for efficient post-processing algorithms and leads to a high resulting rendering quality using enhanced probabilistic EWA volume splatting. In this paper, we focus on the 3D video acquisition system and necessary image and video processing techniques.     

一种快速高效MPEG-4运动估计硬件结构的研究和实现

提出一种高度并行和多流水线处理的硬件结构,实现MPEG-4视频部分的全搜索块匹配运动估计算法.该硬件结构能实时地通过全搜索块匹配运动估计算法来搜索每个像素块最佳匹配运动向量,具有计算速度高、运动向量准确、较少的内置存储器要求、低运行时钟和低功耗等诸多优点,从而可满足移动视频业务和高清晰视频业务的需求.该硬件结构基于富士通的CE66库实现.     

一种MPEG-4 over RTP的实现方法

提出一种使用RTP(Real-Time Transport Protoc01)来传输MPEG．4流的方法。RTP的几个优越的特性能保证MPEG-4流在IP网上的实时传输。另外,使用RTP还能使MPEG．4流与其它的实时数据流保证同步。     

一个改进的MPEG-4码率控制方案

通过分析MPEG-4 Q2中目标比特分配算法的缺陷，根据拉格朗日乘子法，提出了一种保持图像质量一致性的比特分配模型。用新模型替换MPEG-4 Q2中原始的目标比特分配算法，设计出一个改进的MPEG-4 Q2码率控制方案。实验仿真结果表明：改进的MPEG-4 Q2方案不但生成了更加平稳的图象质量，而且大大提高了目标比特的估计精度。     

一种在MPEG-4编码过程中提高实时性的算法

文章提出了一种新的在MPEG-4编码过程中提高实时性的算法。算法采用双重筛选机制,充分利用了运动估计的结果提取运动对象。首先在运动估计过程中加入背景优先准则进行第一重筛选;然后根据运动估计后宏块的最小平均绝对差值利用区域自适应门限进行第二重筛选,从而获得运动区域掩模;最后对掩模进行形态滤波和填充消除噪声点,最终得到运动区域。算法分别在硬件和软件平台上进行测试,结果表明提出的算法得到了理想的分割效果,较传统的在编码前进行运动对象提取的方法实时性大大提高。     

A novel framework for the interactive transmission of 3D scenes

We consider an interactive browsing environment for 3D scenes, which allows for the dynamic optimization of selected client views by distributing available transmission resources between geometry and texture components. Texture information is available at a server in the form of scalably compressed images, corresponding to a multitude of original image views. Surface geometry is also available at the server in the form of scalably compressed depth maps, again corresponding to a multitude of original views. Texture and depth components are both open to augmentation as more content becomes available. At any point in the interactive browsing experience, the server must decide how to allocate transmission resources between the delivery of new elements from the various original view bit-streams and new elements from the original geometry bit-streams. The proposed framework implicitly supports dynamic view sub-sampling, based on rate-distortion criteria, since the best server policy is not always to send the nearest original view image to the one which the client is rendering. In this paper, we particularly elaborate upon a novel strategy for distortion-sensitive synthesis of both geometry and rendered imagery at the client, based upon whatever data is provided by the server. We also outline how the JPIP standard for interactive communication of JPEG2000 images, can be leveraged for the 3D scene browsing application.     

MPEG-4多媒体移动通信系统的一种有效复用结构

介绍了一种基于MPEG－4标准的移动多媒体的两层复用结构。第一层对有相似服务质量（QoS）要求的基本数据流进行打包，形成具有较少QoS要求的数据流；第二层为每个数据流提供相应的防误码措施，形成可在易误码链路进行传输的单一数据流，达到既满足各个基本数据流防误码的要求,又使复用开销最小。     

Display of 3D information in discrete 3D scenes produced by computerized tomography

Imaging modalities such as X-ray computerized tomography (CT), ultrasound CT, and nuclear magnetic resonance CT all produce sequences of slice images of internal structures of medical objects. Effective methods of displaying the 3D information in such images are essential to aid in both diagnosis and treatment of diseases. Two philosophically different approaches to the display problem have been pursued. In the first approach, 3D information is displayed as a distribution of densities in a 3D space. The second approach extracts, from slice images, information about boundary surfaces of objects which is displayed on a 2D screen. The present paper reviews both of these approaches with particular emphasis on the image and graphics processing aspects of the latter approach.     

改进YOLOv4算法的复杂视觉场景行人检测方法

复杂视觉场景下存在过暗或者过曝的光照、恶劣的天气、严重遮挡、行人尺寸差别大以及图像模糊等问题,大大增加了行人检测的难度。因此,针对复杂视觉场景下行人检测准确度低、漏检严重的问题,提出了改进的YOLOv4算法以增强复杂视觉场景下的行人检测效果。首先,构建复杂视觉场景下的行人数据集。然后,在主干网中加入混合空洞卷积,提高网络对行人特征的提取能力。最后,提出空间锯齿空洞卷积结构,代替空间金字塔池化结构,获取更多细节特征。实验表明,在本文构建的行人数据集上,改进后的 YOLOv4算法的平均精度（average precision,AP）达到了90.08%,相比原YOLOv4算法提高了7.2%,对数平均漏检率（log-average miss rate,LAMR）降低了13.69%。     

一种改进的MPEG-4精细可伸缩编码方法

提出了一种改进的MPEG-4精细可伸缩编码方法(巧GS)。在增强层编码中，IFGS增加一个高质量的参考来作为预测补偿，然后利用DCT残差系数的相关性来消除数据冗余。试验结果表明本文提出的改进方法比原来的FGS编码方法有更高的效率。     

An Efficient Embedded Bitstream Parsing Processor for MPEG-4 Video Decoding System

In this paper, the bitstream parsing analysis and an efficient and flexible bitstream parsing processor are presented. The bitstream parsing analysis explores the critical part in bitstream parsing. Based on the result, the novel approaches to parse data partitioned bitstreams are presented. An efficient instruction set optimized for bitstream processing, especially for DCT coefficient decoding, is designed and the processor architecture can be programmed for various video standards. It has been integrated into an MPEG-4 video decoding system successfully and can achieve real time bitstream decoding with bitstream coded under 4CIF frame size with 30 fps, 8Mbps, which is the specification of MPEG-4 Advanced Simple Profile Level 5.Yung-Chi Chang was born in Kaohsiung, Taiwan, R.O.C., in 1975. He received the B.S. and M.S. degrees from the Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan, R.O.C., in 1998 and 2000, respectively, where he is currently pursuing the Ph.D. degree in the Graduate Institute of Electrical Engineering. His research interests include video coding algorithms and VLSI architectures for image/video processing.Chao-Chih Huang was born in Taiwan, R.O.C., in 1977. He received the B.S. and M.S. degree in electrical engineering from National Taiwan University in 2000 and 2002, respectively. In Oct 2002, he has joined the multimedia team of Realtek Taiwan, to be a system design engineer and researched on video coding algorithms. His research interests include video compression/coding and image processing.Wei-Min Chao was born in Taoyuan, Taiwan, R.O.C., in 1977. He received the B.S. and M.S. degrees from the Department of Electronics Engineering, National Taiwan University in 2000 and 2002 separately. His research interests include video coding algorithms and VLSI architecture for image and video processing.Liang-Gee Chen was born in Yun-Lin, Taiwan, in 1956. He received the B.S., M.S., and Ph.D. degrees in electrical engineering from National Cheng Kung University, Tainan, Taiwan, in 1979, 1981, and 1986, respectively. He was an Instructor (1981–1986), and an Associate Professor (1986–1988) in the Department of Electrical Engineering, National Cheng Kung University. In the military service during 1987 to 1988, he was an Associate Professor in the Institute of Resource Management, Defense Management College. In 1988, he joined the Department of Electrical Engineering, National Taiwan University. During 1993 to 1994 he was a Visiting Consultant of DSP Research Department, AT&T Bell Lab, Murray Hill. In 1997, he was a visiting scholar of the Department of Electrical Engineering, University of Washington, Seattle. During 2001 to 2004, he was the first director of the Graduate Institute of Electronics Engineering (GIEE) in National Taiwan University (NTU). Currently, he is a Professor of the Department of Electrical Engineering and GIEE in NTU, Taipei, Taiwan. He is also the director of the Electronics Research and Service Organization in Industrial Technology Research Institute, Hsinchu, Taiwan. His current research interests are DSP architecture design, video processor design, and video coding systems.Dr. Chen has served as an Associate Editor of IEEE Transactions on Circuits and Systems for Video Technology since 1996, as Associate Editor of IEEE Transactions on VLSI Systems since 1999, and as Associate Editor of IEEE Transactions on Circuits and Systems II since 2000. He has been the Associate Editor of the Journal of Circuits, Systems, and Signal Processing since 1999, and a Guest Editor for the Journal of Video Signal Processing Systems. He is also the Associate Editor of the Proceedings of the IEEE. He was the General Chairman of the 7th VLSI Design/CAD Symposium in 1995 and of the 1999 IEEE Workshop on Signal Processing Systems: Design and Implementation. He is the Past-Chair of Taipei Chapter of IEEE Circuits and Systems (CAS) Society, and is a member of the IEEE CAS Technical Committee of VLSI Systems and Applications, the Technical Committee of Visual Signal Processing and Communications, and the IEEE Signal Processing Technical Committee of Design and Implementation of SP Systems. He is the Chair-Elect of the IEEE CAS Technical Committee on Multimedia Systems and Applications. During 2001–2002, he served as a Distinguished Lecturer of the IEEE CAS Society. He received the Best Paper Award from the R.O.C. Computer Society in 1990 and 1994. Annually from 1991 to 1999, he received Long-Term (Acer) Paper Awards. In 1992, he received the Best Paper Award of the 1992 Asia-Pacific Conference on circuits and systems in the VLSI design track. In 1993, he received the Annual Paper Award of the Chinese Engineer Society. In 1996 and 2000, he received the Outstanding Research Award from the National Science Council, and in 2000, the Dragon Excellence Award from Acer. He is a member of Phi Tan Phi.     

因特网环境下MPEG-4视频自适应码率控制方案

介绍了因特网上一种端到端的MPEG-4视频网络传输结构的自适应码率控制方案.结合RTP/RTCP协议,通过终端系统的反馈控制算法,在视频发送端的MPEG-4编码器中由合适的码率调整算法自适应地调整输出码率,从而最大限度地利用网络带宽资源,并且保证视频传输的视觉感知质量.     

Client architecture for MPEG-4 streaming

As Web-based services increasingly include streaming media, broadband service providers must address the challenges inherent in the real-time delivery of high-bandwidth content over a best-effort network. The Multilevel Buffer Architecture is a buffering mechanism for MPEG-4 decoder players, providing a set of services for accommodating network jittering, precise A/V sync, and QoS management.     

An MPEG-4 Renderer for High Quality Video Composition and Texture Mapping

This paper presents the hardware architecture of a co-processor supporting the real time rendering of all 2D natural or synthetic visual objects proposed by the MPEG-4 standard as well as sprite decoding. It enables the composition and the transformation of natural video objects and the texture mapping on triangles, allowing the 2D-mesh decoding. This architecture is able to render scenes that are compliant with MPEG-4 Main Profile, Level3 and Hybrid Visual Profile. The co-processor is designed to be used in a shared memory system architecture. It consists in a dedicated implementation that seeks the best compromise between cost and performances. In a first step, a software model is used to guarantee the visual quality of the rendered scene and to validate the algorithmic choices. Then, the complexity and performances of this novel architecture are evaluated. Finally, a behavioral model validates the architectural choices.     

MPEG-4 multimedia for our time

The MPEG-4 standard explores every possibility of the digital environment. Recorded images and sounds co-exist with their computer-generated counterparts, a new language for sound promises compact-disk quality at extremely low data rates; and the multimedia content could even adjust itself to suit the transmission rate and quality. Possibly the greatest of the advances made by MPEG-4 is that viewers and listeners need no longer be passive. The height of “interactivity” in audiovisual systems today is the users ability merely to stop or start a video in progress. MPEG-4 is completely different: it allows the user to interact with objects within the scene, whether they derive from so-called real sources, such as moving video, or from synthetic sources, such as computer-aided design output or computer-generated cartoons. Authors of content can give users the power to modify scenes by deleting, adding, or repositioning objects, or to alter the behavior of the objects. Perhaps the most immediate need for MPEG-4 is defensive. It supplies tools with which to create uniform (and top-quality) audio and video encoders and decoders on the Internet, preempting what may become an unmanageable tangle of proprietary formats. In addition to the Internet, the standard is also designed for low bit-rate communications devices, which are usually wireless     

在真实的VR场景中嵌入虚拟三维对象

随着虚拟现实技术的发展,其运用涉及的领域也越来越多,涵盖了影视、游戏、旅游以及教育等.在此首先探析了虚拟现实技术的发展现状以及虚拟场景的构建方式,并研究分析如何将三维对象融入到真实虚拟场景中,最后根据虚拟场景技术的实际运用分析总结其优点,希望对大家了解虚拟场景技术有所帮助.     

Motion adaptive intra refresh for MPEG-4

The sensitivity to error of a video bitstream often changes as the amount of motion within a scene changes. Taking this into account, a scheme that attempts to optimise error robustness by varying the amount of adaptive intra refresh blocks is presented. Simulation results demonstrate the benefits of the proposed technique