Multi-Mode Subsurface Sensing and Imaging for Land Mine Detection

The problem of detecting the many types of non-metallic land mines in the presence of widely varying soil background and irrelevant underground clutter is an example of one of the most difficult subsurface sensing problems. The application of a variety of different sensing techniques and modalities, and particularly the processing and fusing of the information from these sensors with signal-processing techniques that take account of the physical operating characteristics of each sensor, appears to be the way to make progress in such challenging applications. The progress of the Northeastern University multi-sensor demining effort funded through the Army Research Office's Multidisciplinary University Research Initiative is surveyed as an example of how this strategy can work.     

Virtual characterization of the time-of-flight neutron reflectometer of the China Spallation Neutron Source

A general virtual experiment for the time-of-flight neutron reflectometer is introduced to simulate the experimental data collection and processing, including instrument simulation, sample modeling, detector simulation, and data reduction. The process mimics the experimental data processing and reduction routines. The reduced data agree well with the theoretical calculation, confirming the reliability of the data reduction algorithms. The methodology and algorithms developed in this study pave the way for the future development of data processing and data reduction software for the time-of-flight neutron reflectometer of China Spallation Neutron Source.     

中子活化技术在矿浆成份分析上的应用

本文阐述了中子活化分析的原理和方法,讨论了瞬发γ射线中子技术在线分析生料浆成份的现场试验和应用情况,结果表明本技术可以满足生产配料的需要。     

Neutron scattering studies of BiFeO3 multiferroics: a review for microscopists

Application of the neutron scattering technique in the study of crystal and magnetic properties of multiferroic BiFeO₃ is presented. The crucial role of the neutron scattering technique, complementary to X-ray diffraction method and transmission electron microscopy, is shown. Especially the ultra high-resolution time-of-flight (TOF) neutron diffraction technique used by Sosnowska et al. to detect the magnetic cycloid ordering and its role in studies of physical properties of BiFeO₃ and its alloys are reviewed. The first inelastic neutron scattering patterns of magnetic excitations in BiFeO₃ are also presented. Applications of different microscopy techniques such as transmission electron microscopy (TEM), scanning electron microscopy ( SEM), field emission TEM and SEM (FESEM and FETEM), magnetic force microscope (MFM) and polarization force microscopy (PFM) bring insight on the fundamental problem of ferroelectricity and confirm the potential of BiFeO₃ multiferroic material for nanoscale devices.     

Anti-Personnel Land Mine Detection and Discrimination Using Acoustic Data

An acoustic-based land mine detection system was field-tested by the University of Mississippi with promising results. This system uses a Laser Doppler Vibrometer (LDV) to measure the velocity of the vibration at the surface of the soil induced by acoustic energy in various frequency bands. In this paper, automated methods for detecting and discriminating Anti-Personnel (AP) mines from clutter objects are presented. Pre-processing methods rely on nonlinear filters realized as Choquet integrals. These filters are robust to the non-Gaussian, impulse type noise in this type of data. Detection follows pre-processing and relies on adaptive thresholding over each frequency band and three-dimensional (3D) connected component analysis. Features are extracted from the 2D frequency slices of the 3D connected components. The features are adaptively aggregated over frequency and used for discriminant analysis. Experiments are performed using anti-personnel mines, clutter objects, and blank areas (background samples with no mines or clutter objects). The algorithm detects 92% of the mines for a wide range of parameters. For some threshold values, 100% of the mines are detected and 92% of the mines are classified as mines with no false alarms.     

Data Processing and Imaging in GPR System Dedicated for Landmine Detection

Improvements of GPR technology can be attained by making adjustments specific for the application of landmine detection on three levels: system design, data acquisition and data processing. In this paper we describe data processing algorithms specially developed for a novel video impulse ultra-wide band front end. With this front end, three-dimensional measurements (C-scans) have been carried out over a controlled test site, using a non-metallic scanner. The test site contained surface-laid and shallow buried landmines, both antitank and antipersonnel, made of plastic, wood, and metal. Because of practical limitations, the data have been acquired on an irregular grid. We have designed data preprocessing and imaging algorithms such that they take into account the specific antenna geometry and its elevation above the ground as well as the irregularity of the data acquisition grid. We show that by tuning the data pre-processing and imaging to the newly designed radar front end and to the particular data acquisition strategy, we obtain clear subsurface images. The resulting images show the ability of the GPR system to detect and visualize small surface laid and shallow buried targets.     

Suppressing GPR Clutter from Randomly Rough Ground Surfaces to Enhance Nonmetallic Mine Detection

This study attempts to quantify the ground penetrating radar rough ground surface clutter by numerical modeling of wave scattering, and establish a strategy to suppress the clutter for given test signals. The goal is to improve the GPR detection statistics for small, buried, low-contrast nonmetallic antipersonnel mines. Using a model of an experimentally measured impulse GPR signal, we simulate the ground surface and buried low-contrast mine target scattered responses. We employ a 2D finite difference time domain (FDTD) method to analyze the pulse shape, delay, and amplitude characteristics of the scattered waves—with and without buried nonmetallic mine targets—as a function of roughness parameters. Five hundred Monte Carlo simulations of various test cases of specified ground root mean square height and correlation length were run to generate statistics for the clutter and target signal variations. In addition, the effectiveness of identifying and removing the ground surface clutter signal for detecting subsurface targets is presented. Results indicate that even with moderate roughness, statistics can be generated to enhance the detection of small, shallow, low-contrast targets.     

红外成像法在GIS设备SF6气体检漏的应用

GIS设备发生SF6气体泄漏会导致其绝缘性能下降,并污染大气环境.红外成像法利用SF6气体特定的红外吸收光谱,能使泄漏气体清晰可见,可在设备运行状况下对泄漏部位进行快速、准确定位.通过对一起220 kV GIS设备SF6气体泄漏的疑难案例的多种检测方法对比,表明红外成像技术对高压电器设备的SF6气体泄漏点的查找,具有安全、高效和全面性特点,为漏气设备检修策略的制定提供可靠的信息.     

Image Processing-Based Mine Detection Techniques: A Review

Various mine detection techniques are reviewed with particular emphasis on signal and image processing methods. Based on the target, mines are classified into two types; anti-tank mine (ATM) and anti-personnel mine (APM). Because of the variety of mine types, current mine detection techniques are diversified. The assumption is made that most mine detection techniques consist of sensor, signal processing, and decision processes. For the sensor part, ground penetration radar (GPR), infrared (IR), and ultrasound (US) sensors are reviewed and their characteristics are summarized for the corresponding output signals. For the signal processing and decision parts, a set of image processing techniques including filtering, enhancement, feature extraction, and segmentation are surveyed. Segmentation is used to extract mine signal from various competing signals. For most image processing techniques covered by this paper, mine detection related experimental results are included or reproduced from existing works.     

中子衍射应力谱仪的垂直聚焦单色器的优化设计

本文应用蒙特卡罗模拟程序MCSTAS对中子衍射应力谱仪的垂直聚焦单色器利用单晶Ge（511）进行聚焦的情况进行了优化计算,得到垂直聚焦单色器的高度和单晶片间的倾角等参数的最佳值;同时对比分析了垂直聚焦单色器与平板单色器两种情况下样品处的中子注量率。最后讨论了单色器起飞角对谱仪分辨率产生的影响。     

矿山测量在煤矿安全生产中的作用

矿山测量主要是为矿山勘探、采矿设计、现场生产指导等提供依据的测绘工作,对整个煤矿的安全生产起到非常重要的作用。通过对矿山测量工作的深入探讨,发现测量在煤矿安全生产中的必要性和作用,为相关领域研究提供参考和依据。     

分布式光纤传感在井下瓦斯检测中的应用

本文从理论上系统分析了分布式光纤传感的原理，并基于载体催化元件的工作特性提出了分布式光纤瓦斯传感的概念。利用瓦斯浓度与元件工作温度的对应关系，可以把瓦斯浓度分布的检测转化为温度分布的检测，初步实验证明该方案是可行的。     

堆用中子探测器校验装置设计

本文采用MCNP4c程序,对影响堆用中子探测器校验装置的各项参数进行计算,确定了装置慢化体厚度、引出孔径等一系列参数.对装置的屏蔽性能进行了计算,结果表明装置屏蔽性能满足标准要求.     

岚县矿区某煤矿井田开拓方式选择

针对矿井工业场地位置选择方案,结合确定的立井开拓方式、矿井井型、煤层赋存条件、开采技术条件、井筒提升设备、井下开拓布置、回采面装备水平和井筒检查孔资料等因素,设计考虑了立井走向长臂开拓方式、斜立井综合开拓方式等三个方案,并进行技术经济比较,最终选用立井开拓、工作面走向布置开拓方案。     

多通道SPR影像传感器及其对生物分子的检测

采用多通道SPR影像传感系统结构,通过不同通道之间的比较,提取待测分子与探针分子之间相互作用所引起的特异性响应,实现了对生物分子相互作用的实时、高精度、动态检测。该传感系统的光路设计使得入射光可以在可能发生共振的角度范围内以不同角度同时照射各个通道,通过SPR影像可以同时检测不同角度入射光线的反射光强。这样,各通道共振角的分布可以方便地实时监测,同时避免了非特异性响应和机械调节带来的误差和不便。     

混凝土结构复杂缺陷的SWRI诊断技术

提出了混凝土结构中任意缺陷的应力波反射成像测试与诊断方法.利用特定的数据采集方法和应力波叠前偏移成像算法,测试预埋复杂形状缺陷的混凝土试件,分别采用不同数量的应力波信号获得了多张叠前偏移剖面图像.试验结果表明,随着应力波数量的增加,叠前偏移剖面能够反映的缺陷区域更广,成像更加清晰.当利用足量应力波信号进行叠前偏移成像处理时,试验结果诊断误差很小,能满足工程的精度要求.     

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。     

基于数字成像技术的自动压接设备故障可视化在线检测方法

为提高自动压接设备故障检测的准确性,提出基于数字成像技术的自动压接设备故障可视化在线检测方法.根据导线压接质量关键工艺参数分析,结合图像处理技术进行自动压接设备的自动标定尺寸分析,采用 X 射线数字成像技术,构建自动压接设备故障可视化在线检测的视觉特征分析模型.通过接续管压接后的无损特征监测,制定耐张线夹及接续管压接后无损检测的判别依据,通过图像视觉特征点标定技术,进行耐张线夹及接续管压接失效点定位.根据脉冲 X 射线数字成像的特征检测,实现对架空导线及自动压接设备的可视化检测和定位.测试结果表明,采用该方法进行自动压接设备定位的准确性较高,平均为 ９６．７％ .     

板中超声导波弧形合成孔径阵列多帧满秩成像检测

超声导波合成孔径阵列作为一种基本的成像方式,其"一发多收"阵列多帧满秩成像具有重要意义。针对板中超声导波弧形合成孔径阵列,运用波幅矩阵和渡时矩阵对弧形阵列接收孔径进行分析讨论,在依次变换发射阵元情况下,研究弧形合成孔径阵列多帧满秩成像和全帧满秩成像。研究结果显示,弧形合成孔径阵列多帧满秩成像可用以表征成像检测区域内散射体信息,弧形阵列自然焦点处多帧满秩图像灰度值基本一致,全帧满秩图像信噪比得到了不同程度增大。由于阵列阵元"边缘效应",阵列边缘阵元所对应的满秩图像背景灰度值增大约50%,全帧满秩图像对比度增大约200%。成像检测试验验证了成像原理的可行性,表明板中超声导波弧形合成孔径阵列多帧满秩成像可有效表征待检区域声场散射信息,研究工作可为深入开展超声导波非规则阵列成像检测研究与应用提供重要基础。     

基于LabVIEW的海底管道内检测轨迹三维可视化成像研究

海底管道内检测技术用于检测管道内部缺损情况和综合评估管道的使用情况,检测人员希望得到尽可能详细的管道检测信息。通过对管道爬行器内置的双轴倾角传感器测得的爬行器不同位置的方位角和顶角,以及里程轮测得的进尺数据,应用上位机和Lab VIEW开发平台,按均角全距法的计算模型,实现管道爬行器检测过程轨迹的三维可视化成像。通过实验验证,具有理论可行性。