基于路面标记的车辆检测和计数

交通监视系统通过采集实时交通流量数据，为智能化交通运输服务和控制管理提供依据，在智能交通系统中有着极其重要的作用。在基于视频图像的交通监视系统中，由路边建筑、树木等物体引起的静态阴影和由运动物体如车辆引起的运动阴影，是导致车辆检测错误的一大主要因素。提出了一种基于路面标记的自动车辆检测算法，用于检测车辆并排除阴影干扰，进而实现对过往车辆进行正确计数，能更可靠地收集各车道的实时车流信息。     

基于单地磁的车辆速度检测方法研究

近年来利用地磁技术进行交通信息检测已发展得较为成熟,但主要应用于停车场车位状态检测,交叉口交通流量和交叉口排队长度数据检测。本文研究提出了一种基于单地磁技术的车辆速度检测方法,利用车辆经过单个地磁检测器引起的不同地磁扰动波形对车型进行分类并建立波形库,通过波形匹配识别经过车辆的车型,由车型确定车辆尺寸长度,结合车辆通过检测器所用时间计算车速。本文对单地磁车辆速度检测也进行了测试,通过与雷达测速仪检测结果对比分析,表明单地磁技术对车辆速度的检测较为稳定,进一步优化后值得推广。     

环形线圈车辆检测器的改进设计

车辆检测器担负着为智能交通系统(ITS)采集数据的任务,具有重要的研究意义.环形线圈车辆检测器具有性能稳定,性价比高,适应性强等优点,市场应用最为广泛.但目前的环形线圈车辆检测器存在误检率较高,且不能对检测数据进行存储.针对上述问题,设计了基于DSP的环形线圈车辆检测器,实验结果证明设计不仅稳定有效,而且降低了误检率.     

一种改进的车辆检测日夜区分方法

在基于视频的智能交通系统中,由于日夜间车辆的检测方法不同,需要在日夜交替时进行相应算法的选择.在分析了现有日夜区分技术不足的基础上,根据日夜间户外视频图像的变化特点,提出了将时间判据和局部图像平均灰度标准差判据相结合的日夜区分方法,并设计了相应的车辆检测算法.实验表明,该方法运用在视频测速系统中,判断时间短、区分准确率高.     

实时车辆流量检测系统的研究

介绍了在智能交通系统中的实时图像处理技术,论述了视频车辆流检测的设计思想,重点介绍了智能交通的核心--车辆检测.根据环境的不同提出不同的检测办法,即白天利用图像序列进行差分运算和夜间利用数学形态学方法.实验数据表明,白天车辆正确识别率在92%以上,而夜间正确率在80%左右.     

基于视频图像的车辆流量实时检测系统

基于运动车辆在视频图像序列中存在颜色变化,提出了基于颜色变化的城市道路车辆流量实时统计检测方法对检测带上的区域进行差分运算,从而快速地检测出运动的车辆;在识别中采用水平投影技术和双差分技术,能够方便、准确地确定车辆阈值并识别出车辆.路面实际检测结果表明该系统的正确识别率可达92%以上,实现了在交通中,对车辆进行智能指挥控制,引导各种车辆行驶,满足了实际应用要求.     

ARM与Linux在交通流量检测中的应用

针对交通流量检测系统的现状,提出了当前系统存在的问题以及可行的改善方法,进而以毫米波雷达作为交通流量信息的传感器设计了基于ARM的交通流量检测器。通过对交通雷达的工作原理和信号处理流程的分析,给出了交通流量检测系统的结构,对ARM控制单元各个模块的硬件电路进行了分析与设计,并移植了Linux操作系统。该设备可以实时的检测交通流量信息,易于扩展,安装维护方便,能够有效地改善现有系统。     

基于车辆侧向特征的视频监控车型分类的研究

智能交通系统(ITS)利用现有的交通资源设施,运用各种先进科学技术解决交通问题得到了充分的发展。ITS的主要任务和关键技术就是车型识别与分类。实验研究了利用基于背景差法的目标提取技术,结合图像处理技术来完成基于车辆侧向特征的视频监控的车型分类,完成了基于图片的目标车辆轮廓提取工作、视频分帧工作、背景差分法提取目标车辆的工作,并且成功的通过测量车长、车高及长高比例这三个参数将车型分类成大车、中型车、小型车三个种类。     

一种基于车辆遮挡模型的车流量统计算法

传统视频检测车流量统计利用车辆跟踪解决遮挡问题,算法复杂且容易受到外界干扰影响,为此建立了若干车辆遮挡模型,利用分层轮廓匹配法将运动目标与车辆遮挡模型进行轮廓匹配识别出遮挡车辆。为了提取运动目标完整外部轮廓,提出一种基于连通域的两轮扫描法来标记各个运动车辆,并利用YUV彩色空间对阴影进行检测和抑制,提高车流量统计精度。实验结果表明,该方法能有效识别遮挡车辆,具有较高的车流量统计精度。     

基于3G网络的车载视频终端系统

介绍一种基于3G网络的车载视频终端系统的设计方案。系统结合了车载视频监控及行车记录仪两大功能,并通过3G网络与监控中心实现音视频数据及行车记录数据等数据的通信传输,以满足在交通系统中的对车辆行驶及车乘人员能提供到更安全有效的保障。     

多工位数控插齿机传送链工况检测与工位控制

介绍一种工件传送链工况非接触检测的反射型红外光电检测装置,并在多工位数控插齿机上实现了在线实时工况检测与工位控制。对检测电路原理,探测器布置原则以及与ＣＮＣ数控系统的互联方式进行了分析。实践表明,该检测装置不仅检测速度快,而且准确性高。     

完善机车运用指标统计的探讨

通过对机车运用工作量指标和运用效率指标的分析，结合铁运处在机车运用统计中存在的问题．提出完善统计指标的方法。     

Quantitative extraction of spectral line intensities and widths from x-ray spectra recorded with gated microchannel plate detectors

Plasma spectroscopy requires determination of spectral line intensities and widths. At Sandia National Laboratories Z facility we use elliptical crystal spectrometers equipped with gated microchannel plate detectors to record time and space resolved spectra. We collect a large volume of data typically consisting of five to six snapshots in time and five to ten spectral lines with 30 spatial elements per frame, totaling to more than 900 measurements per experiment. This large volume of data requires efficiency in processing. We have addressed this challenge by using a line fitting routine to automatically fit each spectrum using assumed line profiles and taking into account photoelectron statistics to efficiently extract line intensities and widths with uncertainties. We verified that the random data noise obeys Poisson statistics. Rescale factors for converting film exposure to effective counts required for understanding the photoelectron statistics are presented. An example of the application of these results to the analysis of spectra recorded in Z experiments is presented.     

Automated control of the velocity of in-tube diagnostic tools for main gas pipelines: I. Development,design, and operating principle of a bypass device

The study considers the development, design, and operating principle of a bypass device integrated into existing in-tube diagnostic tools. The bypass device is designed for automated control of the velocity of in-tube pig flaw detectors in main gas pipelines. Equipment of in-tube diagnostic tools with an automated-control system for the velocity provides performance of in-tube inspection without decreasing gas transportation. This facilitates the flaw detection of main pipelines substantially and makes a dispatcher of a gas-compressor station free of controlling the velocity of passage of in-tube diagnostic tools. The results of assembling a bypass device used for automated control of the velocity of in-tube diagnostic tools for main gas pipelines are considered. Arrangement of the bypass device in existing diagnostic tools for nondestructive testing is based on the experience of development, design, and exploitation of pig flaw detectors, which make it possible to locate the elements of the bypass device without any substantial restructuring of the pig flaw detectors.     

基于PLC的大范围运动与高精度对准控制

针对掩模版传输过程中的大范围运动与高精度对准这两个关键问题，本文采用基于PLC的全闭环位置控制方法，设计了用于掩模版传输和对准的机械手控制系统。对于大范围运动，利用旋转编码器和光栅尺检测机械手的速度和位移，构成三闭环控制系统。对于高精度对准，利用四象限探测器检测掩模版位置与姿态偏差，构成四闭环控制系统。实验结果表明，利用本文控制系统，机械手在大范围传输和高精度对准时的速度和精度都可以满足生产要求。     

Energy-sensitive cryogenic detectors for high-mass biomolecule mass spectrometry

Energy-sensitive calorimetric detectors that operate at low temperatures ("cryogenic detectors") have recently been applied for the first time as ion detectors in time-of-flight mass spectrometry. Compared to conventional, ionization-based detectors, which rely on secondary electron formation or the charge created in a semiconductor, cryogenic detectors measure low-energy solid state excitations created by a particle impact. This energy sensitivity of cryogenic detectors results in several potential advantages for TOF-MS. Cryogenic detectors are expected to have near 100% efficiency even for very large, slow-moving molecules, in contrast to microchannel plates whose efficiency drops considerably at large mass. Thus, cryogenic detectors could contribute to extending the mass range accessible by TOF-MS and help improving detection limits. In addition, the energy resolution provided by cryogenic detectors can be used for charge discrimination and studies of ion fragmentation, ion-detector interaction, and internal energies of large molecular ions. Cryogenic detectors could therefore prove to be a valuable diagnostic tool in TOF-MS. Here, we give a general introduction to the cryogenic detector types most applicable to TOF-MS including those types already used in several TOF-MS experiments. We review and compare the results of these experiments, discuss practical aspects of operating cryogenic detectors in TOF-MS systems, and describe potential near future improvements of cryogenic detectors for applications in mass spectrometry.     

高效液相色谱紫外检测器性能差异的评价

紫外检测器是高效液相色谱最常用的检测器,其噪声、基线漂移等技术参数是仪器的重要性能指标。但仪器在实际使用中常因响应值的标示和单位换算发生变化而产生误差,影响到指标的可比性。本实验在尽可能保证试验条件一致的情况下,对8个不同厂家及型号的紫外检测器的噪声、响应值、不同进样浓度下的信噪比及峰形等参数进行了比较研究,提出了根据特定浓度样品溶液响应的信噪比来评价检测器灵敏度的方法。该方法具有较好的可比性和实用性。实验还表明,不同的检测器对峰形也有影响,并初步探讨了部分差异产生的原因。     

Fast X-ray and Neutron Detectors Based on Natural Diamond

Fast-response detectors based on natural diamond, which has a long charge-carrier lifetime, have been developed and manufactured for performing time-of-flight measurements of the parameters of plasma and other pulsed sources of ultrasoft X-ray and neutron radiations. Detectors of two types—volumetric detectors for detecting neutrons and X rays with quantum energies of >1 keV and surface detectors for detecting ultrasoft X rays with quantum energies of 200–1000 eV—have been manufactured. Their response time is 1–2 ns (the FWHM duration of a current response). The sensitivity of the volumetric detectors to neutrons with an energy of 14 MeV is at a level of 10^–18 C cm²/neutron. The sensitivity of the surface detectors to X rays with an energy of 580 eV is above 5 mA/W.     

Planar Si(Li) detectors with a large active volume

Results of development and investigations of lithium-drifted silicon detectors with a large active volume and an active depth of 4–8 mm for use in multilayer spectrometers are presented. The main performance characteristics of the detectors are described. The detectors have been used to good effect in nuclear radiation spectroscopy, particularly in experimental studies of exotic nuclei at accelerators.     

基于太阳自动跟踪系统的光电探测器设计

在阐述太阳自动跟踪系统的工作原理与国内应用现状的基础上,设计了一种新的用于太阳自动跟踪装置的光电探测器。该探测器具有结构简单、工作精度高等优点,通过理论论证和实验分析证明了其可行性与实用性。