AN ALGORITHM FOR CODING VIDEO SIGNAL BASED ON 3-D WAVELET TRANSFORMATION

This paper presents an algorithm for coding video signal based on 3-D wavelet transformation. When the frame order t of a video signal is replaced by order 2, the video signal can be looked as a block in 3-D space. After splitting the block into smaller sub-blocks, imitate the method of 2-D wavelet transformation for images, we can transform the sub-blocks with 3-D wavelet. Most of video signal energy is in the decomposed low-frequency sub-bands. These sub-bands affect the visual quality of the video signal most. Quantizing different sub-bands with different precision and then entropy encoding each sub-band, we can eliminate inter- and intra-frame redundancy of the video signal and compress data. Our simulation experiments show that this algorithm can achieve very good result.

涉水视觉

地球表面有约71%的面积被江河湖海等水体覆盖,陆地上的成像也会受到云雪雨雾等水体影响,但是,当前常见的机器视觉科研工作和应用系统基本只围绕空气和真空介质中的视觉任务展开,涉及不同形态水体的视觉工作没有得到系统的研究.涉水视觉(water-related vision)作为涉水光学技术在视觉领域的具象化体现,重点研究光与水的物质相互作用及跨介质传播过程中,涉水视觉影像信号智能处理与分析方面的科学问题,以及先进智能涉水视觉装备研制方面的工程技术问题.本文从“为什么大海是蓝色的?”这一具有普适意义的问题出发,系统介绍了水对光的吸收、散射、衰减作用机理,对涉水视觉任务造成的影响,以及现有的涉水图像处理与解析方法.本文基于水体光学特性及成像退化机理,介绍了团队在探索涉水成像和图像解析等涉水视觉关键技术及装备方面的成果,先后研制了全海深超高清相机“海瞳”、全海深3D相机、全海深高清摄像机等,形成了从色彩、强度、偏振、光谱等全方位、体系化的水下观测解析装备研制能力,填补了我国全海深光学视觉技术的空白,推动了我国涉水视觉领域技术的升级,应用价值和社会效益显著.

基于显著特征的Video水印方案

为了使水印的分布集中在Video序列中图像显著的边缘特征中,提出了基于帧图像内容的模糊熵测度(FEM)算法,对序列图像特征系数的修改是局部自适应的,水印嵌入的强度随着图像局部变化而变化.在没有原始Video数据的情况下,利用Kalman滤波预测对水印信息进行检测和估计,能够使嵌入的商标在检测端得到恢复以表明数字产品的版权.实验结果表明,所提出的水印方案,对于Video序列中水印的嵌入及提取具有很好的效果而且可作为可靠的版权保护工具而应用.

电视中心高清视频信号传输优化策略

随着高清视频的普及,电视中心在高清视频信号传输方面面临着巨大的挑战。对此,深入探讨电视中心高清视频信号传输的现状与问题,并提出一系列优化路径,涉及传输协议的优化、编码技术的改进、网络架构的升级以及缓存与流媒体技术的应用。这些措施有望为电视中心的高清视频信号传输带来显著的改进,满足用户对高清视频的需求,推动电视中心的持续发展和竞争力提升。

4K超高清演播室的设计与应用

随着科技的不断突破和传媒产业的飞速发展,观众对于高品质内容的追求已不再满足于传统高清标准。建设4K超清演播室已成为各广播电视台紧要的目标。为此,深入探讨4K超高清演播室的设计方案、优势以及在国内综艺节目录制中的具体应用,为未来演播室的构建提供实质性的指导,推动传媒产业迈向更为美好和前景广阔的未来。

基于多传感器技术深度融合的煤矿井下安全监控技术研究

针对煤矿井下传统安全监控系统存在智能化不足、运维成本较高、现场管控难度较大等问题,对煤矿井下安全监控技术进行了研究。采用多传感器深度融合技术实现对煤矿井下机电设备运行状态参数的全面采集和智能分析诊断,完成硬件系统的设计;采用Labview编写了数据采集监测系统以实现对现场检测数据的可视化显示。现场应用表明,多传感器深度融合煤矿井下安全监控系统实现了对煤矿井下机电设备的智能监控,故障响应时间仅为1.56 s,大大降低了工人的劳动强度,提高了设备的运维效率。该研究结论可以为后期实现煤矿井下设备的智能监控提供一定参考。

基于仿生动态信号的航拍车辆检测算法

现有主流航拍车辆检测算法均针对传统视频设计,但传统视频数据量巨大且存在信息冗余,这些缺点导致现有算法过于复杂且计算量大,运行效率低。提出基于仿生动态信号的航拍车辆检测算法,将整体检测系统拆分为候选目标定位模块与目标检测模块。候选目标定位模块以单个动态事件为输入,结合一定时空邻域内的局部动态事件群,快速定位候选目标。目标检测模块对传统ResNet结构进行改进,提出加入特征融合的M-ResNet以保护浅层特征。此外,制作了时长为25 s,含有295633872个动态事件的车辆事件数据集,通过该数据集验证该文提出算法可快速精准地检测出场景内的车辆。

基于前景区域生成对抗网络的视频异常行为检测研究

为提高视频异常行为检测的准确率,本文提出了一种基于前景区域生成对抗网络的改进方法。通过提取实际视频帧的前景和背景掩码,确定生成对抗网络输出视频帧的待检测前景区域。针对待检测前景区域,应用前景区域峰值信噪比准则,计算异常行为检测得分,完成视频异常行为检测。实验结果表明,本文的检测方法在Avenue数据集、UCSD-Ped1数据集、UCSD-Ped2数据集上均能有效提高视频异常行为检测准确率,并能降低检测运行时间。

基于相机运动轨迹的鲁棒无人机航拍稳像算法

针对高空颠簸环境影响无人机采集延时稳定图像问题,提出了一种适用于悬停拍摄及移动拍摄的航拍视频防抖算法。通过无人机摄像头获取延时摄影视频,提取全局范围内的部分视频帧进行直方图分布比较,进而确定视频是否是在无人机移动状态下拍摄的,并将视频划分为包含与不包含摄像机主动运动两类。对于包含摄像机主动运动的一类,首先,采用FAST角点检测加光流法进行特征点提取配对;其次,利用RANSAC算法剔除误匹配特征点并进行摄像机运动轨迹估计;最后,利用高斯滤波对运动估计参数进行平滑以得到稳定的摄像机运动轨迹。对于不包含摄像机主动运动的一类,首先,对首帧进行网格划分并基于Harris矩阵提取各网格的特征点;其次,在后续帧对这些特征点进行光流追踪;再次,通过反向光流及Harris矩阵计算,增加特征点约束,完成特征点提取及匹配;最后,利用保留的特征点估计后续帧至首帧的稳定变换。利用该算法对视频进行场景分类及画面稳定,实验结果表明:视频分类模块能正确区分两类视频;对比其他两种方法,稳定后的视频图像平均峰值信噪比提升更大;对于不含摄像机主动运动的视频,可实现画面绝对稳定,图像平均峰值信噪比提升超过39%,而其他两种方法仅提升10%~12%。

一种基于改进SIFT的视频稳像方法

为提高计算效率并保持良好的稳像效果,本文提出一种基于改进SIFT的视频稳像方法。首先对SIFT进行改进,并命名为BO-SIFT(Binarized Octagonal SIFT)。该算法引入了同心八边形环特征描述子,通过降维和二值化对特征向量进行处理,然后使用汉明距离进行特征点匹配,有效缩短了描述和匹配时间。其次将BO-SIFT算法应用于视频稳像,提取视频帧的特征点进行匹配,并计算出帧与帧之间的运动偏移量,以此实现运动估计。最后采用卡尔曼滤波器对估计出的运动偏移量进行平滑处理,并利用仿射变换对视频帧进行逆向补偿,从而得到稳定的图像序列。实验结果表明:相较于原始的SIFT算法,BO-SIFT算法使稳像时间减少了56.404%;相较于现有的较好算法,BO-SIFT算法稳像后的视频具有更高的平均峰值信噪比。此外,本文算法在不同视频上进行稳像效果测试,也具有一定的可靠性和优越性。

Detecting Objectionable Videos

This paper addresses the problem of detecting objectionable videos, which has never been carefully studied before. Our method can be efficiently used to filter objectionable videos on Internet. One tensor based key-frame selection algorithm, one cube based color model and one objectionable video estimation algorithm are presented. The key frame selection is based on motion analysis using the three-dimensional structure tensor. Then the cube based color model is employed to detect skin color in each key frame. Finally, the video estimation algorithm is applied to estimate objectionable degree in videos. Experimental results on a variety of real-world videos downloaded from Internet show that this method is promising.

电声信号编解码技术在网络多媒体传输中的应用

探讨电声信号编解码技术在网络多媒体传输中的应用,重点分析音频、语音、视频编解码的原理和关键技术。通过实际案例剖析,揭示了编解码技术在复杂网络环境下的优化措施,如自适应码率控制、智能分路由、错误恢复机制等,有效提升了多媒体传输的质量和稳定性。

Adaptation of Video Services in ATM Networks

Transmission and switching of video services will be the important services provided bythe information superhighway,in which ATM(Asynchronous Transfer Mode)will be one ofthe key techniques.This paper discusses the adaptation of video services in ATM networksand presents a scheme of implementation.As a component of an ATM network supported bythe High Technology Research and Development Programme of China,the circuit designedwith the principle works successfully.

Hardware Implementation and System Control Strategy of Videoconference System Based on Rec. H. 261

The design and realization of a videoconference system based on international recommendation are introduced in this paper, and the hardware implementation of video codec based on ITU-T H. 261 is briefly discussed. Furthermore, the buffer control method and the adaptive control strategy for quantization are proposed, which are adaptive and robust. This system can be operated under the transmission rate ranging from 128kb/s to 2Mb/s. With these strategies for the videoconference system, the high quality image is obtained. The time delay of the system is about half a second.

Video quality based link adaptation for low latency video transmission over WLANs

Wireless Local Area Networks (WLANs) such as IEEE 802.11a/g and Hiperlan/2 utilise numerous transmission modes, each providing different throughputs and reliability levels. Many link adaptation algorithms proposed in the literature either maximise the error-free data throughput based on channel conditions or are based on the number of failed transmissions. However, these algo- rithms do not take into account the content of the data stream and strongly rely on the use of Automatic Repeat Requests (ARQs). Low latency video applications such as real-time video transmission may require no retransmission, or only a limited number of retrans- missions. Moreover, completely error-free communication is not essential, especially if robust video compression techniques are applied. In such scenarios, improved decoded video quality can be obtained with a video stream transmitted at a higher bit rate using a higher link speed but with some degree of transmission error, rather than an error-free video stream at a lower bit rate using a lower link speed. In this work, we investigate a link adaptation scheme that improves the Quality of Service (QoS) for video transmission, based on the overall received video quality (Peak Signal to Noise Ratio, PSNR), rather than by maximising the error-free throughput. We also study a practical link adaptation approach that uses PER thresholds at the PHY layer. An empirical study showed that thresholds for switching from one mode to another are much lower (almost error free) than those currently used by throughput based schemes. We show that traditional link adaptation strategies are not appropriate for real-time video transmission with no retransmis- sion. Simulation results using the H.264 video compression standard over IEEE 802.11a are presented.

Designation and Realization of Softswitch-based Remote Video-monitoring System

In this paper, architecture of softswitch-based Next Generation Network (NGN) system and Session Initiation Protocol (SIP) are studied briefly, and the problems on the openness and extensibility of normal remote video-monitoring system (RVMS) are analyzed. Then a RVMS framework model based on softswitch is given. Furthermore, designation and realization of the system based on T 6000 Softswitch Platform is provided. The innovation is considering the RVMS as a part of softswitch system. It is a feasible scheme for implementing next generation video-monitoring system based on broadband IP technique.

地面数字电视单频点同播4套高清节目的实践及视频质量评估

本文提出了一种利用视频质量评估来优化地面数字电视单频点同播高清节目套数的方法。根据我国地面数字电视(DTMB)信道编码、城市无线覆盖的实际情况,以及编码复用前后的视频序列,进行客观视频质量评估计算结果,优化播出设备参数,实现在保证终端接收视频质量的前提下,尽量提高数字电视无线传输覆盖的频带资源的利用效率。

Efficient Rate Control Algorithm for Hierarchical Video Coding

For rate control (RC) of hierarchical structure coding, an independent rate-quantization (R-Q) model was proposed based on mean absolute differences (MADs) in different temporal levels (TLs). In the proposed R-Q model, a novel MAD model was developed according to the hierarchical structure. The experimental results demonstrate that the proposed algorithm provides better performance, in terms of average peak signal-to-noise ratio (PSNR) and quality smoothness, than the H.264 reference model, JM14.2, under various sequences.

Performance of Quantization Factor in H.261 Video Coding

The quantizaion factor through buffer pure occupy algorithm is provided. Through the simulation, firstly the relationship between quantization factor and compression ratio is analyzed, secondly the PSNR of the image with the quantization factor is discussed, and finally the control to the output rate of the coder by adjusting the value of quantization factor is studied.

VIDEO TRANSMISSION SYSTEM IN ITV APPLICATION

The transmission characteristics of video transmission mediums,coaxial ca ble and optical fiber,are discussed in the paper. The formulas for frequency bandwidth are given to evaluate the video transmission distance. For typical video transmission systems with BB/IM and PFM/IM tising optical fiber as the channel, expressions and calculating results for both S/N and sensitivity are given. Finally, the principle for se lecting different type of transmission systems according to transmission distances of the industrial TV is presented.