Quality Assessment and Measurement for Internet Video Streaming

Benefiting from the improvements of Internet infrastructure and video coding technology, online video services are becoming a new favorite form of video entertainment.However, most of the existing video quality assessment methods are designed for broadcasting/cable televisions and it is still an open issue how to assess and measure the quality of online video services. In this paper, we survey the state-of-the-art video streaming technologies, and present a framework of quality assessment and measurement for Internet video streaming. This paper introduces several metrics for user's quality of experience(QoE).These QoE metrics are classified into two categories: objective metrics and subjective metrics. It is different for service participators to measure objective and subjective metrics.The QoE measurement methodologies consist of client-side, server-side, and in-network measurement.

Research on the measurement of belt speed by video in coal mine based on improved template matching algorithm

In order to improve the intelligence of video monitoring system of belt and make up the deficiency of higher failure rate and bad real-time performance in the traditional systems of measurement of belt speed, according to the fact that the light of coal mine is uneven, the strength of light changes greatly, the direction of belt movement is constant, and the position of camera was fixed, various algorithms of speed measurement by video were studied, and algorithm for template matching based on sum of absolute differences （SAD） and correlation coefficient was proposed and improved, besides, the tracking of feature regions was realized. Then, a camera calibration method using the invariance of the cross-ratio was adopted and the real-time measurement of belt speed by the hardware platform based on DM642 was realized. Finally, experiment results show that this method not only has advantages of high precision and strong anti-jamming capability but also can real-time reflect the changes of belt speed, so it has a comprehensive applicability.

VM700T视频测量仪的校准方法的改进

针对传统VM700T视频测量仪的校准方法的局限性,提出了新的校准方法。介绍了TG2000电视测试信号发生器和信号编辑程序SDP2000,给出了VM700T校准信号的编制过程。使用实验室的VM700T对校准信号的各项失真参数进行了验证,与编制时的设定值基本一致。实现了VM700T对具体失真参数的测量准确度的校准,提高了校准工作的技术水平。

基于LabVIEW和VideoMASTER的视频自动测量系统

基于LabVIEW和VideoMASTER的视频自动测量系统可以很好地完成对模拟/数字、复合/分量、标清/高清等各种形式视频信号参数的自动测量。可以根据需求自主选择测量项目,并能够给出完整的符合要求的计量报告,使视频计量一气呵成,大大提高了工作效率。

VideoLog可视化测井油管接箍自动识别方法

在可视化测井中,深度对于判断油管缺陷位置至关重要,而现有的测深系统具有一定的深度误差。实际工程中,可通过识别油管接箍再参照油管数据表来准确标定仪器的深度。本文基于运动视频图像处理,提出了一种油管接箍自动识别方法。利用VideoLog可视化测井系统采集井下油管视频图像,通过对视频图像进行形态学处理、特征参数提取、接箍判决等过程来准确识别接箍。实验结果表明,同一个接箍在视频中会多次出现,也会被多次识别到,同一接箍平均识别率为86.9%,接箍计数的正确率为100%。方法已成功用于可视化测井视频解释处理中,取得了较好的工程应用效果。

Recent Developments of Image Based Measurement Methods for Application to Transonic Flows in Industrial Wind Tunnels

The experimental investigation of unsteady complex flow fields in wind tunnels requires advanced measurement techniques. The most important of such image based measurement techniques are those for the measurement of planar flow velocity fields, planar pressure distribution, model location and deformation, model temperature and quantitative high speed flow visualization. The applications as carried out by DLR range from low speed flows to transonic flows, from high lift configurations to propellers and rotors, from wake vortex investigations in catapult facilities and water towing tanks to investigations of vortex break down phenomena on delta wings. The capability to use image based measurement techniques in transonic flows requires dedicated technical developments and experienced scientists due to the special environment of a transonic wind tunnel. In this paper an overview of the state-of-the art of the application of image based measurement techniques in transonic flows as performed by DLR＇s Institute of Aerodynamics and Flow Technology will be given.

Experimental Modal Damping Identification of a Mechanical Structure Using Video Magnification Technique

Vibration can be introduced in all mechanical fields in our life.Engineers try to avoid its negative effect leading in some cases to deformation in the machines.Many researches are dedicated to study the identification of damping especially in multi degree of freedom systems with particular attention to the source of energy dissipation.They focus on developing new tools or methods which may be used in real problems to obtain accurate results about the amount(or value)and the location of energy dissipation in the structure.The aim of this paper is to present an original procedure aims to experimentally determine the modal damping ratio of a mechanical structure.The proposed procedure consists of extracting the Frequency Response Function of the vibrating system using the video magnification method and then calculate the modal damping ratio using the 3-dB method.These experimental measurements are carried out by giving an external force on a cantilever beam,then the modal damping ratios are extracted using motion magnification.The obtained results show a relative error less than 4.2% between the experimental measurements and the analytical calculation for the Frequency Response Function(FRF)curves.The novelty of the paper is to combine the video magnification technique and the 3dB method in a procedure that aims to experimentally measure the modal damping of a mechanical structure.The proposed procedure in this paper represents the damping identification as a simple and easy engineering application.

A CAD-based inspection planning strategy for video measuring instrument

A CAD-based inspection planning strategy for video measuring instrument is proposed to improve manufacturing effec- tiveness. The system consists of a video probe that enables itself to inspect a work piece based on a CAD model. The measurement software includes CAIP module and MDP module. The CAIP module is developed based on a CAD development platform whose kernel is the Open CASCADE. The entire system was tested, and relevant examples show that the system can accomplish automatic inspection planning task for common parts efficiently.

安讯士发布新视频存储系统——AXIS VMS N16-Z

安讯士网络通讯继发布Axis Camera Companion和AXIS Video Management Software两款视频管理软件之后,又新发布一款特别针对中国市场推出的视频存储系统——AXIS VMS N16-Z。这款产品是一款将视频查看、录像、回放和事件管理等功能融于一体,为用户提供全方位的视频监控解决方案。

关于NI VMS视频测量软件对电视视频信号发生器进行校准的研究

该文以美国国家仪器(NI)生产的NI PXI-5122数据采集卡结合NI VMS视频测量软件来代替VM700系列视频分析仪对电视视频信号发生器进行校准,简述校准步骤,并对相关不确定度进行评定。

基于视频的振动测量技术研究进展

振动测量是保障结构安全和良好状态的基本手段。高精度的振动测量可为结构设计、安装调试、健康管理等振动试验提供精确的输入与响应测试。相较于传统的振动测量手段,基于视频的振动测量技术将相机的全部像素转化为高精度振动传感器,利用视频图像方式让人们肉眼可视结构在物理世界的真实振动形态,具有非接触、全视场、高空间分辨率、灵活方便等优点,近年来受到业界的广泛关注。该文主要介绍了视频振动测量技术的系统构成与测量过程、当前主要方法和相关技术最新进展,并总结了视频振动测量技术与其他技术相比存在的优势。通过分析与对比,肯定了视频方法是解决振动测量问题的有效手段和对传统测量方法的有力补充,随着相关技术和硬件设备的发展,视频振动测量方法将具有越来越大的研究意义和应用价值。

一种基于虚拟仪器技术的视频分析仪校准装置

针对视频分析仪校准中主要标准器停产以及校准过程繁琐的问题,基于虚拟仪器技术,在LabVIEW开发环境下,利用M4i.6622-x8任意波形发生卡作为信号发生模块,开发了一种视频分析仪校准装置。实现了视频分析仪基本参数和失真参数的校准,给出了亮度电平、色度电平、色度相位等视频基本参数和行倾斜、k_(p)系数(2T脉冲k系数)、色度-亮度增益差、色度-亮度时延差、亮度非线性失真等视频失真参数的校准信号产生过程。经过实验,技术指标可达到如下:亮度电平为±0.2%,色度电平为±0.2%,色度相位为±0.1°,行倾斜为±0.1%,k_(p)系数为±0.1%,色度-亮度增益差为±0.2%,色度-亮度时延差为±3 ns,亮度非线性失真为±0.2%;优于TG2000可编程视频信号发生器,满足视频分析仪校准要求。

基于深度学习的水域实例分割尾矿库干滩长度测量

提出了基于YOLOv8的水域实例分割方法,实现了在实时视频流下快速、高效、准确的尾矿库干滩长度测量。首先,完成一份高质量水域实例分割的COCO数据集;其次,分析主流深度学习实例分割算法,选用YOLOv8模型训练出高效识别水线并输出图像坐标;最后,标定相机内外参数,应用相机成像原理,在尾矿库尾部安装监控摄像头,预测出干滩长度。实验证明:此模型不仅能够准确预测出干滩长度,并且对不同尾矿库水域边界分割有较好的稳定性;对实时视频流模式下的野外非接触式测量具有较好的效果,误差控制在2%以内。

超大基坑施工变形风险预控技术研究——以深圳某枢纽工程为例

深州市某综合交通枢纽14号线基坑为密贴运营地铁7号线车站的异形深大基坑,施工风险大。首先建立三维有限元分析,明确了基坑和运营车站围护结构变形较大、存在安全风险的位置为运营7号线车站靠近14号线基坑侧的地下连续墙,以及14、24号线基坑交汇处阳角位置的14号线基坑地下连续墙,应作为现场监测重点区域;结合传统监测和视频识别等自动化监测手段,对风险位置的围护结构变形进行详细监测和评估,视频识别监测结果表明,地下二层开挖引起地下一层围护结构整体变形小于2 mm,基坑结构处于安全状态。通过建立现场监测和风险预案体系,保证了基坑施工过程风险可控。

基于连续学习的视频物联网任务需求理解与调度方法

云网资源与视频任务的高效调度是保障视频物联网(video Internet of things,VIoT)应用性能的关键.然而,目前运营化VIoT所用调度算法对差异化的任务需求和高度动态的云网资源变化适应能力不足,导致VIoT应用性能不佳.针对上述问题,提出了一种基于连续学习的视频物联网任务需求理解与调度方法(continuous learning-based task demand understanding and scheduling method for VIoT,CLTUS).与传统启发式或机器学习驱动的调度算法不同,将连续学习引入云网资源与视频任务需求的匹配中.首先,基于通用的连续学习框架实现各类视频任务需求的准确理解;其次,依据视频任务之间的需求依赖关系,实现任务与服务器的适配,以精细化调度云网资源;最后,将所提方法部署于软件定义的VIoT实验平台上.与传统方法相比,CLTUS不仅将视频任务的平均处理效率提高了127.73%,还将云网资源利用均衡率提高至67.2%,有效增强了VIoT应用性能.

非匀速条件下车辆底盘超近距成像测量方法

针对车辆非匀速条件下轴距视觉测量及轴型识别所面临的超近距、大幅面、低畸变成像及视觉测量问题,提出一种适用于非匀速条件下的车辆底盘结构超近距成像测量方法。利用鱼眼相机采集运动车辆底盘的超广角图像序列,通过一种改进的多采样点圆拟合方法实现图像感兴趣区域的提取。建立三维等距成像模型对鱼眼图像进行畸变校正。针对车辆非匀速行驶带来的视频帧重叠度差异,采用基于图像内容的重叠度分析技术,实现了多步分层的关键帧提取,有效避免了车速不稳定对车辆底盘结构测量的影响。现场实验结果表明:该方法可在非匀速条件下,以20~50 cm的成像距离获得清晰、低畸变的完整车辆底盘图像,车辆轴距测量误差均值约为5%。

基于视觉与激光融合的柔性压裂管线检测机器人

柔性压裂管线作为一种新型压裂管汇,能有效提升压裂作业时管线连接效率。为了保障柔性压裂管线安全服役,并面向现场使用需求,研制了一种基于视觉与激光融合的柔性压裂管线检测机器人。机器人主要由爬行装置、视频检测装置、激光旋转检测装置和控制模块组成,并基于混合现实技术提高机器人检测交互体验。机器人通过视频检测和激光测量分别获得柔性压裂管线的图像信息与轮廓信息,在此基础上综合评估管线内部橡胶层磨损状况,从而有效预测和规避柔性压裂管线失效风险。最后,通过试制样机开展试验,验证了该机器人能够满足设计需求,具备较好的推广前景。

特高压变压器视频监控智能巡检系统研究与应用

分析了传统视频监控技术在应用中的局限性,提出一种基于高清网络摄像机的视频监控智能巡检系统,讨论了该系统的组成、网络结构、点位选取等内容;通过该系统在某特高压变压器巡检上的应用,将系统在可见光巡视、套管红外测温、现场表计读数等方面的巡检结果与人工巡检进行比对,验证了该系统的准确性和实效性,保障了变电运维人员巡检过程中的人身安全,提高了设备巡视质量。

视频测流技术在汤溪水文站的应用研究

该文介绍了武大AiFlow视频测流技术在汤溪水文站的应用结果,以汤溪水文站2023年10月—2024年1月走航式ADCP实测结果与武大AiFlow视频测流数据进行率定分析,结果表明:断面流量系统误差为0.08%,随机不确定度为13.50%,关系曲线检验中的符号检验、适线检验、偏离数值检验均合格,符合《水文资料整编规范》(SL/T 247—2020)的规定要求,实现了水库出库流量的自动化监测需求,为现代化水文站建设及智慧水利数字孪生系统发展提供了有力支持。

河冰视频监测技术研究

本文分析了河冰视频监测的特点,围绕相机标定及投影转换、河冰特征识别、流冰速度解算等方面,系统介绍了河冰视频监测应用现状及关键技术,并提出应用过程中亟待解决的关键问题,为河冰视频监测技术研究提供了参考依据。