Wavelet-based acoustic detection of moving vehicles

We propose a robust algorithm to detect the arrival of a vehicle of arbitrary type when other noises are present. It is done via analysis of its acoustic signature against an existing database of recorded and processed acoustic signals to detect the arrival of a vehicle of arbitrary type when other noises are present. To achieve it with minimum number of false alarms, we combine a construction of a training database of acoustic signatures signals emitted by vehicles using the distribution of the energies among blocks of wavelet packet coefficients with a procedure of random search for a near-optimal footprint. The number of false alarms in the detection is minimized even under severe conditions such as: the signals emitted by vehicles of different types differ from each other, whereas the set of non-vehicle recordings (the training database) contains signals emitted by planes, helicopters, wind, speech, steps, etc. The proposed algorithm is robust even when the tested conditions are completely different from the conditions where the training signals were recorded. The proposed technique has many algorithmic variations. For example, it can be used to distinguish among different types of vehicles. The proposed algorithm is a generic solution for process control that is based on a learning phase (training) followed by an automatic real-time detection.

基于RFID的轨道车辆实时定位系统设计

为了使目前轨道车辆运行效率提高,采用射频识别RFID技术对轨道车辆的物理位置进行实时监测的方法,提出一种利用RFID技术对轨道车辆进行实时定位的系统,并介绍该实时定位系统的设计方案、组成及工作原理,主要包括RFID标签安置、RFID读写及与后台服务器通信等技术。系统运行性能结果表明利用RFID技术对轨道车辆进行实时定位具有精度高、环境适用性强等优点,在地铁和企业厂段的轨道车辆实时定位中具有良好的应用前景。     

一种新型实时快速滚转角测量系统

针对滚转角测量系统中的实时快速图像处理需求,提出一种基于泰伯-莫尔效应的计算量小、快速高效并且精度高的图像处理算法。首先,对干涉图像进行频域滤波和空域中值滤波,去除噪声并平滑保留图像边缘;然后采用自适应二值化进行阈值分割,再进行细化并去除毛刺,剪切图像去除效果差的边缘数据;最后采用一种霍夫变换和最小二乘法求解条纹间隔进而求得滚转角。实验结果表明,测量误差小于2.5 arcsec,在PC机上完成一次运算时间约为400 ms。所采用的算法提高了图像处理速度。全部算法采用ANSI C编程实现,可移植到不同的嵌入式图像处理系统中,提高了算法的通用性和实用性。     

Seismic source model for moving vehicles

We develop a method for the loading of ground by moving vehicles in large finite-difference time-domain simulations of seismic wave propagation. The objective is to realistically produce two distinct types of ground loading for either wheeled or tracked vehicles in our propagation models: lower frequency loading associated with suspension dynamics and higher frequency impulsive loading associated with tire treads or wheels rolling over individual track blocks. These loading characteristics are important because field measurements show that vehicle ground forcing in both frequency bands produces seismic surface waves that networked sensors can remotely process for security applications. The method utilizes a vehicle-dynamics model to calculate a response to vehicle acceleration and ground features such as bumps; calculates forces transmitted to the ground; distributes these forces to staggered points of a finite-difference model; and simulates seismic wave propagation away from the vehicle. We demonstrate the method using bounce-and-pitch models of wheeled and tracked vehicles. We show that by carefully preprocessing force inputs, we can accurately simulate wave propagation and seismic signatures in finite-difference analyses of vehicles moving continuously over terrain.     

网络漏洞实时入侵检测系统

在分析国内外入侵检测系统的现状、构件方法、运行特点等基础上，结合实际需要提出开发一个基于公共漏洞列表（CVE）的实时入侵检测专家系统。以国际公开的CVE列表所列漏洞为主要研究对象，实现了实时入侵检测。     

一种实用化实时测温系统的测温灵敏度

基于基尔霍夫定律,利用半导体激光器InGaAs/I及钽酸锂热释电探测器设计了一种实用化的实时测温系统。基于该系统A/D转换器件的分辨率、V(T)-T曲线的温度灵敏度及其与测温范围间的制约关系,确定了系统应选用16位的芯片为其A/D转换器件;基于该系统的测温精度、V(T)-T曲线的相对温度灵敏度及其与波长间的关系,对其工作波长的优化选择进行了进一步的讨论;基于探头的温度分辨力、A/D转换器件的分辨率以及与V(T)-T曲线的温度灵敏度间的制约关系,对其波长带宽的优化设计进行了进一步的分析,并给出了系统在673K～1473K内的测温灵敏度。对系统进行优化设计后,在测温范围的低温段,其灵敏度不低于0.5K;在测温范围的高温段,则不低于0.1K。在673K～1473K内,其测温不确定度不低于0.3%。     

A real-time detector for parked vehicles based on hybrid background modeling

In this paper, a real-time detection system based on hybrid background modeling is proposed for detecting parked vehicles along the side of a road. The hybrid background model consists of three components: (1) a scene background model, (2) a computed restricted area map, and (3) a dynamic threshold curve for vehicles. By exploiting the motion information of normal activity in the scene, we propose a hybrid background model that determines the location of the road, estimates the roadside and generates the adaptive threshold of the vehicle size. The system triggers a notification when a large vehicle-like foreground object has been stationary for more than a pre-set number of video frames (or time). The proposed method is tested on the AVSS 2007 PV dataset. The results are satisfactory compared to other state-of-the-art methods.     

基于FPGA的视频实时边缘检测系统

于对视频图像检测与识别的需要,提出了一种基于FPGA的视频边缘检测系统设计方案,并完成系统的硬件设计.通过FPGA控制摄像头进行视频采集,双端口SDRAM对图像数据进行缓存,FPGA再对数据进行实时处理.实际采用DE2-115开发板和CMOS摄像头OV7670为硬件平台进行验证.结果表明,该系统具有实时性高,检测准确的特点,达到了设计要求.     

A scheme for high performance real-time BER measurement

A statistically based method of bit error rate (BER) which does not necessitate the transmission of test patterns or the interruption of data for measurement purposes is presented. It is demonstrated that the method allows accurate estimation of BER several orders of magnitude faster than the Monte Carlo method. Design of an optimal BER estimator based on the maximum-likelihood principle is proposed. The performance of the technique is demonstrated by simulations for the case of QPSK modulation in AWGN and for a live Rayleigh-fading HF link. The ability of the method to accurately predict BER using relatively few samples means that it is particularly suitable for high-speed BER estimation     

随车压实度实时检测系统研究

在借鉴传统检测方法的基础上,根据压路机振动信号与压实程度的相关关系,提出了一种随车压实度实时检测系统。该系统利用振动传感器采集压路机振动信号,并将该信号进行A/D转换,放大、滤波,在时域和频域进行数字信号处理,进而提取出压实度实时数值。通过大量现场试验验证,本系统计算出的压实度值与传统压实度检测结果,具有高度的一致性和准确性。     

冷库温度实时巡回检测系统设计

针对冷库温度实时检测的需要,设计了一个冷库温度实时巡回检测系统。系统由硬件和软件两部分组成,硬件部分主要包括DS18B20检测电路、显示电路、报警电路、晶振电路、复位电路等,软件部分主要包括串口温度采集与显示、超限报警、用户信息管理等。实验表明,系统工作稳定,达到预期的目的。     

A scalable VideoGIS system for GPS-guided vehicles

A VideoGIS system aims at combining geo-referenced video information with traditional geographic information in order to provide a more comprehensive understanding over a spatial location. Video data have been used with geographic information in some projects to facilitate a better understanding of the spatial objects of interest. This paper presents an on-going VideoGIS project, in which scalable geo-referenced video and geographic information (GI) are transmitted to GPS-guided vehicles. The hypermedia, which contains cross-referenced video and GI, are organized in a scalable (layered) fashion. The remote users can request, through 3G mobile devices, the abundant information related to the objects of interest, while adapting to heterogeneous network condition and local CPU usage. Available bandwidth estimation technique is used in the adaptive video transmission.     

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.     

基于晶体管测量的中子注量在线实时测量系统

利用晶体管直流放大倍数的倒数与中子注量呈线性关系这一特点,使用晶体管作为在线中子注量测量的探测器,建立了以计算机、GPIB总线、矩阵开关、任意波形发生器、数字示波器等硬件为基础,基于LabVIEW软件平台的中子注量在线实时监测系统。在西安脉冲反应堆中子辐射场中,开展了标定实验研究,建立的中子注量在线实时监测系统实现了空间分布的中子注量实时测量,利用该套系统得到了XAPR和CFBR-Ⅱ的等效损伤系数。     

运动热钢坯外形尺寸在线测量系统的设计

阐述了应用面阵电荷耦合器件测量运动热钢坯外形尺寸的测量系统。该系统采用面阵ＣＣＤ摄像，经Ｂｔ８１２数字化器进行视频信号采集，运用ＡＤＳ完成图像处理与识别，最后由工业控制４８６微机输出测量结果。     

A real-time optical sensor for simultaneous measurement of three-DOF motions

The need for simultaneous measurement of multiple degree-of-freedom (DOF) motions can be found in numerous applications such as robotic assembly, precision machining, optical tracking, wrist actuators, and active joysticks. Conventional single-axis encoders, though capable of providing high-resolution (linear or angular) measurements, rely on mechanical linkages (that often introduce frictions, backlashes, and singularities) to constrain the device so that the three-DOF (3-DOF) motion can be deduced from the individual orthogonal measurements. We present here a noncontact optical sensor for 3-DOF planar and spherical orientation measurements. We begin with the operational principle of a microscopic-surface-based optical sensor. The design concept and theory of a dual-sensor system capable of measuring 3-DOF planar and spherical motions in real time are then presented. Along with a detailed analysis, the concept feasibility of two prototype 3-DOF dual-sensor systems for measuring the instantaneous center of rotation and the angular displacement of a moving surface is demonstrated experimentally. It is expected that the analysis will serve as a basis for optimizing key design parameters that could significantly influence the sensor performance.     

A linear-induction-motor propulsion system for high-speed ground vehicles

The design and development status of a linear-induction-motor propulsion system intended for use on high-speed ground vehicles is described. In this system, 3-phase, 60-Hz, 8250-V wayside power is converted by a solid-state power conditioning unit to a variable-voltage variable-frequency output suitable for use by linear-induction motors that provide up to 66 600-N (15 000-lb) propulsive thrust to the vehicle at 480 km/h (300 mi/h). The system provides continuously variable thrust during forward- and reverse-thrust modes, and such special features as automatic start-up, regenerative braking, and automatic failure/malfunction detection and shutdown. The system incorporates high-voltage water-cooled components for high specific thrust (more than 5 N/kgf, or 0.5 lbf thrust/lbf weight).     

运动目标视觉跟踪测量系统与场地坐标系的快速统一方法

车载移动式视觉跟踪与测量系统在实际应用中, 快速便捷地进行视觉系统与场地坐标系的全局统一是关键技术。结合视觉系统与现场特点, 阐述了系统标定原理, 给出了视觉跟踪与测量系统相对于场地坐标系转换数学模型。该方法的基本思路是转台视轴分别指向场地坐标系内的两个控制点, 根据两点对应的俯仰角、方位角及距离确定两坐标系的转换关系。仿真分析和实验结果表明: 角度和距离精度分别达到0.03和0.52%。该方法便捷、高效, 对移动式视觉测量系统坐标系快速统一有实用价值。     

深海垂直剖面实时监测系统的设计与实现

为了对深海动力环境进行监测,设计了一种深海垂直剖面实时监测系统。系统利用浮力调节的方法实现测量平台沿系留索升降,在升降的过程中进行海洋剖面参数的测量,同时将测量数据通过感应耦合传输和卫星通信的方式传送给岸站。突破了水下大背压条件下浮力调节技术和海上数据实时通信传输技术,实现了深海动力环境的实时测量。     

An electronical system for real-time measurement of the logarithmic magnitude of scattering parameters

An electronical system for real-time measurement of scattering parameters of millimeterwave two-ports is described. In order to achieve a suitable measurement accuracy, the output signals of the millimeterwave detectors and the characteristic of the measurement amplifier should be matched. For this reason the detector power-characteristic is approximated by help of a polygon and it is realized with a few nonlinear amplifiers. The theoretical background and experimental results show the applicability of the measurement system presented here.