数字式JC-MV系列视频测量仪的功能

四川川嘉电子有限公司自行研制的“嘉测牌”视频测量仪具有很强的测量功能,而且还在不断扩充新的功能。1测量测量方式有两种：波形测量和指标测量。其中指标测量分为自动测量和手动测量。自动测量具有自动检测功能。1）波形测量在这种测量状态下,视频测量仪有点类似示波器,不过这种示波器要准确得多,而且相当稳定。另一方面,屏幕上还有4条光标线。调整光标位置,可以十分准确地得出测量数据,显示在图形下方。同时,图形可以上下、左右移动,也能够放大、缩小。助自动测量进行自动测量之前,应该先设置系统。系统的设置包括两方面。首…     

一种基于PLL同步的循环周期脉冲信号计量方法

详细分析了循环周期脉冲信号异步测量方法的计量误差,指出了影响测控系统计量精度的主要原因,提出了基于锁相环(PLL)同步的新方法。该方法能有效消除测控系统的计量误差随传感器工作状态变化的因素,在PLL内部计数频率高于系统CPU工作频率的情况下,可以有效提高系统的计量精度,同时,可以自动实现传感器测量信号的归一化运算,避免CPU的除法运算负担,从而有效提高测控系统的实时性。最后给出了具体应用PLL同步计量方法的实用测量接口电路。     

GTEM室性能测量系统研制

吉赫兹横电磁波室(GTEM室)是电磁兼容领域重要的测试场地。为解决GTEM室性能测量问题,从GTEM室场均匀性、TEM模的测量原理入手,中国计量科学研究院研制了GTEM室性能测量系统及配套软件。经实验验证,系统完全符合IEC 61000-4-20:2022要求,可以实现GTEM室内各测量位置点处的三维电场分量、GTEM室净馈入功率等参数的自动测量以及场均匀性、TEM模的自动计算。GTEM室性能测量系统工作稳定,原始数据采集及处理准确可信。目前中国计量科学研究院已具备依据IEC 61000-4-20:2022对外开展GTEM室性能测量服务的能力。     

播出视频通道的自动测量

在电视播控系统的维护中，经常要对视频的各项指标进行测量。我们使用的测试仪器是泰克公司的ＶＭ７００Ａ，它可以手动单项测量，也可以进行自动测量。手动单项测量虽然可以设置参考，把信号源的误差排除，但由于每项指标的测量过程都需要频繁重复的操作步骤，使得操作人...     

功率计的自动计量测试系统

计量测试是研制、生产的重要保证手段,自动计量测试是今后多项目、宽范围、高速度、高准确度测量的唯一途径。本文介绍了采用ＧＰＩＢ总线构成的一种功率自动计量测试系统的组成的程序设计。     

一种电量母线不平衡异常计量点定位软件

<正>本文介绍了一种基于电力计量自动化系统所获得的电能数据，并根据变电所的电能不均衡率与变压器损耗数据之间的内在联系，实现了对变电所数据存在的测量数据进行自动诊断和快速定位的方法。这种方法可以充分发挥计量自动化系统的实时性，并能自动地定位变电所的测量值，使操作和维修人员能够快速、有效地发现和解决这些问题，从而提高计量系统的测量精度。该方案可以有效地控制电厂的不均衡率，使仪表准确、公正、可靠地运行。1母线有功平衡简介母线功率平衡描述为：在此基础上，假定输入一个结点的有功是正的，而离开这个结点的有功是负的，那么，该结点上的有功的代数和为0。     

K_a波段六端口精密测试系统

一、概述六喘口精密测试系统是国际上第三代网络计量设备,被人们誉为"科学珍品"和"单人计量实验室".第一代网络计量设备是开槽测量线等.60年代早期和中期发展了矢量网络分析仪技术,接着推出了计算机控制,在一系列步进频率点上测量网络参数,并自动修正误差和处理数据的自动网络分析仪,这就是第二代网络测量设备.其优点是测量精度高,测量过程     

用视频显微镜实现显微干涉计量的实验研究

采用视频显微镜作为显微成像和电子记录的工具进行显微干涉计量,光路简洁,调整方便.用显微云纹干涉系统和显微散斑干涉系统分别测量了物体的面内变形、离面位移和物体的形状.实验结果表明视频显微镜可应用于各种显微干涉计量场合.     

用微机控制的视频 音频信号切换器

电视台控制中心应用微机可以实现程序自动操作、信号自动切换、故障自动查询、显示、告警等一系列功能。本文介绍了采用微机控制的6×6视频/音频切换矩阵的实现方案及主要电路的设计原理,并对其软件的设计作了说明。一、系统的组成及工作原理 6×6视频/音频切换矩阵要实现的是将6路输入信号(视频、音频)送到6个输出通道(每个输出通道包括视频、音频),而任意一个输出通道可选择任意一路输入信号输出。鉴于切换矩阵的工作要求,我们用图1所示的框图来实现微机控制的信号切换矩阵。 6路视频和六路音频信号,经各自的输入分配电路进行阻抗匹配射随后,分别送到6个     

热成像系统NETD自动测量方法研究

论述了红外热成像系统NETD测量的理论基础,设计了一种该参数的自动测量方法,并搭建了试验平台.该平台先设置不同温差的靶标,再通过采集卡将热像仪的模拟视频采集到计算机,然后通过WINDOWS程序对数据进行处理,最后计算出热像仪的NETD.试验结果表明,该参数的自动测量可以工程化实现.     

Measurement of video initial buffer size for mobile network

To resolve the difficulty in accurately measure the length of video initial buffering queue,two video platforms,non-encrypted Youku and encrypted YouTube,were selected to research,and the video initial buffer queue length measurement method was proposed.By identifying and analyzing the characteristics of video traffic,correlating the traffic behavior with the playing state,constructing video fingerprint database,accurate measurement of queue length was realized.The experimental results show that the measurement results of the two types could be accurate to the frame,fully meeting the need to accurately evaluate the quality of the video experience.     

A locally adaptive algorithm for measuring blocking artifacts in images and videos

Block transform coding is the most popular approach for image and video compression. The objective measurement of blocking artifacts plays an important role in the design, optimization, and assessment of image and video coding systems. This paper presents a new algorithm for measuring image quality of a BDCT coded images or videos. It exhibits unique and useful features: (1) it examines the blocks individually so that it can measure the severity of blocking artifacts locally; (2) it is a one-pass algorithm in the sense that the image needs to be accessed only once; (3) it takes into account the blocking artifacts for high bit rate images and the flatness for the very low bit rate images; (4) the quality measure is well defined in the range of 0–10. Experiments on various still images and videos show that the new quality measure is very efficient in terms of computational complexity and memory usage, and can produce consistent blocking artifacts measurement.     

Video QoS enhancement using perceptual quality metrics

As the market for broadband video services matures, the ability to deliver high-value video content will become increasingly important. For the telecommunications industry to compete effectively with other video providers, it is vital that the quality of video services matches the expectations of customers. A major challenge lies in ensuring that the trade-off between price and quality is acceptable to consumers of broadband video. This paper introduces a new method for measuring in real-time the perceptual quality of video. The potential operational benefits of this method are discussed. The paper describes how a no reference video quality measurement method may be deployed as a mechanism for quality control at the point of video encoding and transmission. Further, it is proposed that a real-time video quality metric can be used to measure the quality received on end users’ devices. By applying perceptual quality measurements for quality control and feedback, this mechanism can be used to ensure adequate quality is delivered to customers, make more efficient use of bandwidth and thereby reduce backhaul costs, and act as a quality assurance check on the customer’s end device.     

Using edge direction information for measuring blocking artifacts of images

Block-based transform coding is the most popular approach for image and video compression. The objective measurement of blocking artifacts plays an important role in the design, optimization, and assessment of image and video coding systems. This paper presents a new algorithm for measuring blocking artifacts in images and videos. Instead of using the traditional pixel discontinuity along the block boundary, we use the edge directional information of the images. The new algorithm does not need the exact location of the block boundary thus is invariant to the displacement, rotation and scaling of the images. Experiments on various still images and videos show that the new blockiness measure is very efficient in terms of computational complexity and memory usage, and can produce blocking artifacts measurement consistent with subjective rating.     

A system for real-time measurement of the brachial artery diameter in B-mode ultrasound images.

The measurement of the brachial artery diameter is frequently used in clinical studies for evaluating the flow-mediated dilation and, in conjunction with the blood pressure value, for assessing arterial stiffness. This paper presents a system for computing the brachial artery diameter in real-time by analyzing B-mode ultrasound images. The method is based on a robust edge detection algorithm which is used to automatically locate the two walls of the vessel. The measure of the diameter is obtained with subpixel precision and with a temporal resolution of 25 samples/s, so that the small dilations induced by the cardiac cycle can also be retrieved. The algorithm is implemented on a standalone video processing board which acquires the analog video signal from the ultrasound equipment. Results are shown in real-time on a graphical user interface. The system was tested both on synthetic ultrasound images and in clinical studies of flow-mediated dilation. Accuracy, robustness, and intra/inter observer variability of the method were evaluated.     

A System for Real-Time Measurement of the Brachial Artery Diameter in B-Mode Ultrasound Images

The measurement of the brachial artery diameter is frequently used in clinical studies for evaluating the flow-mediated dilation and, in conjunction with the blood pressure value, for assessing arterial stiffness. This paper presents a system for computing the brachial artery diameter in real-time by analyzing B-mode ultrasound images. The method is based on a robust edge detection algorithm which is used to automatically locate the two walls of the vessel. The measure of the diameter is obtained with subpixel precision and with a temporal resolution of 25 samples/s, so that the small dilations induced by the cardiac cycle can also be retrieved. The algorithm is implemented on a standalone video processing board which acquires the analog video signal from the ultrasound equipment. Results are shown in real-time on a graphical user interface. The system was tested both on synthetic ultrasound images and in clinical studies of flow-mediated dilation. Accuracy, robustness, and intra/inter observer variability of the method were evaluated     

雷达低空目标俯仰角事后提取的动态偏差补偿技术

由于多径回波信号的干扰，雷达对低空目标俯仰角的实时测量很难达到靶场外弹道测量的精度要求。结合目前靶场在装雷达系统，研究了掠海巡航飞行低空目标的俯仰角事后提取问题，为了提高低空目标俯仰角的测量精度，应用动态偏差补偿技术从雷达系统实时存储下来的视频信号中提取低空目标俯仰角参数。结果显示，动态偏差补偿技术可以显著改善俯仰角测量精度，为靶场试验决策提供依据。     

基于千兆网的高帧频视频采集系统

高帧频视频图像采集是测试技术领域的重要组成部分,系统根据B码时统的高精度信号,由控制计算机通过软件修正摄像机曝光信号时间,实现了高帧频视频图像和测控数据的同步采集,设计了一种无信息损失的高帧频(1 000 F/s)、高分辨率视频图像和测控数据同步采集系统。利用千兆以太网把图像数据从相机的FLASH内无失真转储到计算机硬盘内,并在转储过程中把同步测量数据合成到对应的图像帧频上。     

Detection of colour biases in video images

Due to improper use of television broadcast equipment and/or reference whites in colour video cameras, a colour bias is often introduced into a video image. In excessive amounts, this bias is noticeable and can be annoying to the viewer. An attempt to objectively measure the degree and nature of the colour bias is described. By artificially introducing a colour bias into an existing colour image and constructing a third-order histogram where the histogram is a function of the levels (gray levels) in the red, green, and blue components, certain useful features of the degraded image are obtained. An estimate of the histogram rotation in the three-dimensional colour space is made. This estimate of the rotation, expressed as a real-valued number, is a measurement of the colour bias in the image     

基于嵌入式操作系统的码流检测仪的设计

主要介绍了嵌入式实时操作系统及在数字电视广播码流监测方面的开发应用。以研究开发用于监控数字电视网络信号的码流监测仪为例，阐述了怎样开发具有网络功能的嵌入式设备。