一种低编码复杂度可分级的视频编码系统

在可分级视频编码（SVC,scalable video coding）的框架下,利用分布式视频编码（DVC,distributed video coding）技术,设计了一种低编码复杂度的SVC方案。该系统具有空间可分级的特性,各分层中仅用到了传统的帧内编码技术和DVC技术,最大限度的减小了SVC系统的编码复杂度。在该...     

Image/video communications: joint source/channel coding

Transmission of image/video messages over communication networks is becoming a standard way of communication due to very efficient compression algorithms that reduce required channel capacity to an acceptable level. However, all compression standard techniques are strongly sensitivitive to channel disturbances and their application is suitable only for practically noiseless channels. In standard noisy channels, the effect of errors on a compressed data bit stream can be divided into two categories: systematic errors defined by the structure of data blocks, and random errors caused by amplitude changes of transmitted components. A systematic error can be detected at the receiver through control of the data stream structure and corrected by error concealment methods or by automatic repeat request (ARQ) procedures. Random errors, noise and burst‐like errors, as well as impulse noise, should be controlled through channel coding. It is reasonable that an integrated source and channel coding methods should be preferred and should give better coding performance. In this paper, a new framework for an image/video coding approach has been presented in which the source and channel coding is integrated in a unique procedure. Image compression is performed in a standard way of the JPEG algorithm based on discrete cosine transform (DCT) and error control coding is based on the real/complex‐number (N,M) BCH code using discrete Fourier transform (DFT) specified with zeros in the time domain, i.e. with roots in the frequency domain. Efficiency of the proposed method is tested on two examples, an one‐dimensional real‐valued time sequence coded by real‐number (20,16) BCH code using DFT, and an example of an image coded by complex (10,8) BCH code using DFT with the correction ability of up to 8 impulses per transmitted 8×8 block. In addition, two decoding methods based on Berlekamp–Massey algorithm (BMA) and the minimum‐norm algorithm (MNA) have also compared. Copyright © 1999 John Wiley & Sons, Ltd.     

Adaptive packet scheduling for scalable video streaming with network coding

Over the last decade, the emergence of new multimedia devices has motivated the research on efficient media streaming mechanisms that adapt to dynamic network conditions and heterogeneous devices’ capabilities. Network coding as a rateless code has been applied to collaborative media streaming applications and brings substantial improvements regarding throughput and delay. However, little attention has been given to the recoverability of encoded data, especially for the streaming with a strict deadline. This in turn leads to severe quality of experience. In this paper, we solve the unrecoverable transmission by proposing a multi-generation packet scheduling problem, which is treated as a video quality maximization problem and solved using dynamic programming algorithm. Experimental results confirm that the proposed algorithm brings better data recoverability and better quality of service in terms of video quality, delivery ratio, lower redundancy rate under different network sizes.     

基于CUDA技术的视频显示系统的设计与开发

NVIDIA 推出的CUDA（计算统一设备架构）是基于GPU 进行通用计算的开发平台,非常适合大规模的并行数据计算。在GPU 流处理器架构下用CUDA 技术实现编码并行化,并针对流处理器架构特点进行内存读写等方面的优化。在此采用CUDA技术,实现了计算机桌面环境的多屏幕融合显示的纯软件拼接系统。该系统不但较以往单一的视频拼接系统功能更加强大,也较采用分屏器等硬件辅助的融合系统成本更低,适应性更强。目前实验表明,CUDA 技术在并行处理方面的优越性使得该系统画面实时处理快,互动展示性好,具有很大的商业使用前景。     

基于Windows平台实现视频信号编解码

提出了一种基于Windows95/98平台的视频信号压缩编解码方案，实现了视频信号的接收处理和播放，测试结果表明该方案编程效率大大提高，对视频信号的处理性能稳定可靠，播放图像性能良好。     

基于最大可容忍深度失真模型的低复杂度深度视频编码

在保证虚拟视点绘制质量的前提下,如何降低深 度视频的编码复杂度是一个亟需解决的问题。本文提出了一 种基于最大可容忍深度失真(MTDD,maximum tolerable d epth distortion)模型的低复杂度深度编码算法,将MTDD模型引 入 到率失真(RD)代价函数,通过对编码单元(CU)进行失真度量判决 ,如果对当前CU进 行编码不会导致可察觉的绘制失真,则失真度量只考虑深度编码失真,否则失真度量同时考 虑深度编码失真和视点 合成失真(VSD),从而降低编码复杂度。实验结果表明,所 提出的算法在不 降低虚拟视点绘制质量和不增加编码码率的情况下,能显著降低深度视频的编码复杂度。     

基于Delaunay三角形网格的彩色视频帧间编码方法

充分利用彩色视频亮度和色度分量之间的相关性,提出了一种基于DT网格的彩色视频帧间编码方案。该方案在运动估计时仅对亮度分量Y进行DT(Delaunay triangulation)描述,对亮度分量的网格节点进行连续运动估计,利用6参数方法得到三角形内像素点的运动矢量,经过相似变换得到色度分量的运动矢量。另外对残差图像进行特殊处理和编码。实验结果表明,相对于适合低码率传输的H.263编码方法,在相同的压缩比下该方案解码图像有更好的主客观质量。     

A signal adaptive diffusion filter for video coding: Mathematical framework and complexity reductions

In this paper we combine video compression and modern image processing methods. We construct novel iterative filter methods for prediction signals based on Partial Differential Equation (PDE) based methods. The mathematical framework of the employed diffusion filter class is given and some desirable properties are stated. In particular, two types of diffusion filters are constructed: a uniform diffusion filter using a fixed filter mask and a signal adaptive diffusion filter that incorporates the structures of the underlying prediction signal. The latter has the advantage of not attenuating existing edges while the uniform filter is less complex. The filters are embedded into a software based on HEVC with additional QTBT (Quadtree plus Binary Tree) and MTT (Multi-Type-Tree) block structure. In this setting, several measures to reduce the coding complexity of the tool are introduced, discussed and tested thoroughly. The coding complexity is reduced by up to 70% while maintaining over 80% of the gain. Overall, the diffusion filter method achieves average bitrate savings of 2.27% for Random Access having an average encoder runtime complexity of 119% and 117% decoder runtime complexity. For individual test sequences, results of 7.36% for Random Access are accomplished.     

Iterative search strategy with selective bi-directional prediction for low complexity multiview video coding

The multiview video coding (MVC) extension of H.264/AVC is the emerging standard for compression of impressive 3D and free-viewpoint video. The coding structure in MVC adopts motion and disparity estimation to exploit temporal and inter-view dependencies in MVC. It results in a considerable increase in encoding complexity. Most of the computational burden comes from uni-directional and bi-directional prediction. In this paper, an iterative search strategy is designed to speed up the uni-directional prediction in MVC. It can work with an adaptive search range adjustment through a confidence measure of a loop constraint to obtain both motion and disparity vectors jointly. Furthermore, a selective bi-directional prediction algorithm is proposed to enhance the coding performance by analyzing the statistical characteristics of bi-directional prediction in MVC. Experimental results demonstrate that, by using the proposed fast search, the temporal and inter-view redundancies of multiview video can be eliminated sufficiently with low complexity.     

分析视频图像的压缩传输技术

介绍视频图像信号的压缩传输技术,简单论述几种压缩编码方式,讨论基于MPEG－2编码的视频图像传输计划,阐述JPEG2000编码系统整体流程,并研究JPEG2000中对视频图像进行压缩的相关传输技术。     

Low complexity shape-adaptive DCT for coding of arbitrarily shaped image segments

A low complexity shape-adaptive DCT transform algorithm for coding pels in arbitrarily shaped image segments is presented. The proposed algorithm is compared to the well established generalized shape-adaptive transform method introduced by Gilge et al. in terms of transform efficiency and computational complexity. Results obtained under both theoretical and experimental conditions show that the new algorithm achieves a transform efficiency close to that of the Gilge method with considerably reduced computational complexity. The proposed shape-adaptive DCT algorithm was implemented into a standard MPEG-1 coder to provide object or segment based coding of images and video with additional content-based functionality. The extended MPEG-1 object based coding scheme can handle generic input sequences and can readily provide MPEG-1 backward compatibility if no contour data is transmitted for a given video sequence. Results for INTRA coding of images indicate that the algorithm allows efficient coding over a wide range of coding parameters — thus providing means for generic coding of segmented video between very high and very low bit rates. It is further shown that some of the content-based based functionalities currently discussed in MPEG-4 can be provided efficiently using the proposed object based coding scheme.     

基于最小二阶导数的低复杂度视频背景建模算法

为了训练出适应于视频压缩域的高质量背景模型,该文根据像素点在时域上的分布特征,提 出一种基于最小二阶导数的低复杂度视频背景建模算法。首先,根据函数 的二阶导数性质来判断其波动特性;然后,通过二次差分拟合像素点在时域上的二阶导数, 得到各个像素点的稳定 性;最后,根据设定阈值分离出各个位置的像素点在训练周期内最平稳的值,将其作为相应 位置的背景模型值。实 验结果显示,与AVS2相比,BD-rate节省了9.83%,BD- PSNR提升了 0.37 dB。与AVS2-S的背景建模算法相比, 本算法有效改善了前景污染问题,降低了算法复杂度。     

Deterministic properties of separable and cross median filters with an application to block truncation coding

In this paper, we present some deterministic properties of separable and cross median filters. It is proved that in the absence of vertical binary oscillations, the roots of a separable median filter are included in a subset of root signals of the corresponding cross median filter. Moreover, the sufficient and necessary condition is given for a point to be invariant to cross median filtering. On the root structures of cross median filters, we indicate that there exist three different types of regions based on the one-dimensional features of rows and columns. Finally, an application example is discussed where the roots of separable and cross median filters are used in block truncation coding (BTC) for image compression.     

Design of a systolic-pipelined architecture for real-time enhancement of color video stream based on an illuminance-reflectance model

A high performance digital architecture for the implementation of a nonlinear image enhancement technique is proposed in this paper. The image enhancement is based on an illuminance-reflectance model which improves the visual quality of digital images and video captured under insufficient or non-uniform lighting conditions. The algorithm shows robust performance with appropriate dynamic range compression, good contrast, accurate and consistent color rendition. The algorithm contains a large number of complex computations and thus it requires specialized hardware implementation for real-time applications. Systolic, pipelined and parallel design techniques are utilized effectively in the proposed FPGA-based architectural design to achieve real-time performance. Approximation techniques are used in the hardware algorithmic design to achieve high throughput. The video enhancement system is implemented using Xilinx's multimedia development board that contains a VirtexII-X2000 FPGA and it is capable of processing approximately 63 Mega-pixels (Mpixels) per second.