基于CSIFT的彩色图像配准技术研究

图像配准在计算机视觉、遥感、医学诊断与治疗、环境监测等领域有广泛的研究应用.目前,多数算法是将彩色图像转化为灰度图后再配准,色彩信息的丢失可能会引起误配准.为此,提出一种基于CSIFT(Colored scale invariant feature transform)的彩色图像配准方法,求出彩色图像各个位置处的颜色不变最,以颜色不变量作为输入图像,再提取特征点并描述特征点周围的信息,通过最近邻匹配法求出图像问的匹配对,最后利用匹配的特征求取图像间的变换参数及配准后图像.实验结果表明,对彩色图像进行已知参数值变换时,该算法能得到精度高、误差小的计算结果;对变换关系末知的彩色图像,也能准确地求出图像间的映射关系;且多数情况下运行速度较SIFT(Scale invariant feature transform)快.     

‘Operational health’ monitoring for confidence in long term electric field measurements

The paper describes practical aspects of electrostatic fieldmeter instrumentation for long term monitoring of electric fields in adverse environmental conditions. Examples of applications have been in studies of tank washing on large crude oil tankers and measurement of atmospheric electric fields. Particular attention is drawn to the technique developed for continuous monitoring of operational health to justify confidence in observations.     

面向复杂装备的信息融合式健康监测分析研究

为解决当前复杂装备维修维护与状态监测所面临的问题,提出面向复杂装备的信息融合式健康监测;对复杂装备健康监测需求进行研究,明确针对复杂装备开展健康监测研究的意义;完成装备健康监测概念辨析,明确将信息融合技术引入复杂装备健康监测的意义;对信息融合技术国内外研究现状进行分析,针对信息融合技术的数据级、特征级及决策级,对各层级典型信息融合算法进行概要分析;论文研究为后续进一步深入开展复杂装备信息融合式健康监测研究奠定了良好基础。     

基于LED照明的色差评价研究

截止目前,多国相关颜色科学工作者已累计提出了40多个色差公式,但是目前所有的色差公式的相关使用,都只能限定在CIE给定的观测条件。固态照明作为近些年光源研究的重点方向,相关的研究如基于LED照明条件的色差研究仍未展开。该研究遵循CIE的色差研究指导原则,首先选取CIE推荐的17种颜色中心中的五种颜色,制成实验色块样张,分别以U30,TL84和D65光源为参考光源,以LED灯泡为实验光源。选用CIE1976LUV色差公式、CIE1976LAB色差公式、CIEDE2000色差公式分别对打印色块进行理论色差值的计算。然后采用20名观察者,通过心理物理学的视觉评价实验对打印色样进行主观色差评价,最后通过标准化残差平方和(STRESS)将客观计算值与主观评价数据进行对比分析。发现实验中选用的三种色差公式在LED照明条件下的色差预测性能均不是很理想。相比而言,在LED照明条件下,CIE1976LUV公式的预测性能相对要好,CIEDE2000公式次之,CIE1976LAB公式最差。     

基于彩色直方图分析的智能视频监控系统

针对背景为固定场所的数字视频监控系统，提出了一种通过比较图像彩色直方图距离实现视频监视系统自动控制的方法.通过在线动态更换参考图像，消除了时间变化引起的阳光、天气等因素对背景图像的影响.采用均匀压缩的方法，将真彩色颜色空间压缩到16色的索引色空间，降低了计算复杂度，滤掉了背景的微小变化引入的噪声，实现了10 ms内完成对一幅图像的处理.准确的自动控制在保证监视系统正常工作的同时，极大地减小了所需的存储空间. 关键词： 视频监视系统 彩色直方图 直方图距离     

Temperature corrected sensor diagnostics for impedance-based SHM

Previously, a sensor diagnostics method has been developed for the impedance-based structural health monitoring technique. Impedance techniques utilize piezoelectric patches bonded to the structure of interest for inference of damage. Measuring the slope of piezoelectric susceptance allows unhealthy sensor to be identified. While this sensor diagnostics technique is very useful in detecting damaged sensors bonded to a structure, the method is also susceptible to temperature variations. The object of this study is to accurately provide sensor diagnostics at any temperature. The model developed should be accurate and easy to implement on health monitoring hardware. A frame structure is fabricated to simulate a real structure with complex boundary conditions for experimental testing in various thermal environments. A model predicting piezoelectric susceptance slope at any temperature is generated and validated on the frame structure in an extended temperature range.     

基于几何代数的彩色光流场计算

提出了一种新的基于几何代数的彩色光流场计算方法.从新的角度出发讨论了运用几何代数的概念来解决彩色图像序列的可行性和简便性.在几何代数域内对彩色图像序列用多重矢量表示,证明了彩色光流场分析时进行约束条件时的测量问题,通过多重矢量而非多通道的图像处理方法来表示图像连续特性,从而扩大了测量范围;然后依据物体色彩在运动过程中保持不变的原理,在几何代数域内推导了彩色图像序列的光流约束方程及其解法.结果表明,该算法能够显著提高各种情况下的彩色光流场计算能力.     

基于数码相片和颜色空间转换的滨海土壤盐渍化定量估算

土壤盐渍化是土壤退化的重要原因之一,快速精确地监测土壤盐渍化对农业可持续发展和生态环境保护有积极作用。提出一种基于数码相片的滨海地区表层土壤盐分的定量估算方法,旨在复杂天气状况下快捷方便的获取土壤盐分信息。以江苏盐城沿海地区裸露地表土壤作为研究对象,在晴天和多云天气下全天时采样和拍照获取52个土壤样本和相片。土壤样品通过室内测试获取土壤电导率（EC）,pH值和土壤含水量等参数。利用RStudio软件对土壤相片进行处理,首先从相片中提取RGB三种颜色参数,再通过颜色空间转换关系计算另外5种颜色空间（HIS,CIEXYZ,CIELAB,CIELUV和CIELCH）,每个颜色空间有三个颜色参数,加上RGB颜色空间共有18个颜色参数,其中CIELAB,CIELUV和CIELCH中L参量表示的意义和数值相同,因此6个颜色空间共有16个颜色参数。土壤电导率与颜色参数相关分析结果表明,相片颜色的纯度和亮度与土壤电导率之间的相关系数较高,并达到了极显著水平,相片颜色的色相与土壤电导率之间的相关性较低,且未达到显著水平。随机抽取70%的样本数据并用随机森林方法对土壤盐分含量进行建模,采用留一法（LOOCV）进行交叉验证,再用余下30%的样本数据进行精度检验,重复100次以获取精度最高的模型。最终获取估算土壤盐分的随机森林模型,验证集数据的模型精度达到R2_val=0.75,RMSE_val=3.52,RPD_val=2.02。对颜色参数进行重要性分析发现,颜色纯度对模型的重要性最大,其次是颜色亮度,色相的贡献较小。综上,利用数码相机获取表层土壤相片,通过颜色空间转换得到的颜色参数为有效估算滨海土壤盐分含量提供一个新思路。该研究对近地表参数定量估算提供了新视角,将来结合无人机平台能够为精准农业和滨海生态环境的精准管理提供技术支持和有效手段。     

Measurements of atmospheric potential gradient fluctuations caused by corona ions near high voltage power lines

High voltage power lines produce corona ions which can create disturbances in the Earth's vertical potential gradient. It has been hypothesised that these ions mediate adverse health effects such as the observed increase in leukaemia near to power lines. A fixed site monitoring station has been installed near two high voltage power lines which measures the vertical potential gradient throughout the year in all conditions. Ten minute samples of time varying potential gradient are sorted by wind direction to indicate whether the monitoring station is downwind of a power line and assessed for its variability by calculating mean, inter-quartile range and the number of turning points. Mean and inter-quartile range are related to wind direction, showing higher values when the wind is coming from the power lines.     

高重复频率激光脉冲作用下KTP晶体中的灰迹

采用波长为1 064 nm/532 nm、脉宽6 ns(FWHM)的高重复频率调Q激光,研究了磷酸氧钛钾(KTP)晶体中灰迹的产生机理,以及色心密度对灰迹的影响。晶体透过率表征了色心密度,根据透过率与色心密度的关系以及色心密度对灰迹产生的决定作用,定义临界灰迹密度,当晶体透过率高于此值时可安全运行,而低于此值时,为避免晶体发生灾难性损伤应立即停止运行。实验结果表明:灰迹不仅大量吸收紫外及可见光能量,而且大量吸收近红外波段能量,这为灰迹的在线监测提供了一种监测方法。     

Roller bearing acoustic signature extraction by wavelet packet transform,applications in fault detection and size estimation

Continuous online monitoring of rotating machines is necessary to assess real-time health conditions so as to enable early detection of operation problems and thus reduce the possibility of downtime. Rolling element bearings are crucial parts of many machines and there has been an increasing demand to find effective and reliable health monitoring technique and advanced signal processing to detect and diagnose the size and location of incipient defects. Condition monitoring of rolling element bearings, comprises four main stages which are, statistical analysis, fault diagnostics, defect size calculation, and prognostics. In this paper the effect of defect size, operating speed, and loading conditions on statistical parameters of acoustic emission (AE) signals, using design of experiment method (DOE), have been investigated to select the most sensitive parameters for diagnosing incipient faults and defect growth on rolling element bearings. A modified and effective signal processing algorithm is designed to diagnose localized defects on rolling element bearings components under different operating speeds, loadings, and defect sizes. The algorithm is based on optimizing the ratio of Kurtosis and Shannon entropy to obtain the optimal band pass filter utilizing wavelet packet transform (WPT) and envelope detection. Results show the superiority of the developed algorithm and its effectiveness in extracting bearing characteristic frequencies from the raw acoustic emission signals masked by background noise under different operating conditions. To experimentally measure the defect size on rolling element bearings using acoustic emission technique, the proposed method along with spectrum of squared Hilbert transform are performed under different rotating speeds, loading conditions, and defect sizes to measure the time difference between the double AE impulses. Measurement results show the power of the proposed method for experimentally measuring size of different fault shapes using acoustic emission signals.     

Spectral Based Color Correction Technique Compatible with Standard RGB System

A spectral turn method is presented as a spectral based color correction method compatible with the standard RGB system by applying the idea of a multi-spectral method. The multi-spectral based color reproduction technique has been proposed for providing independent color of device and viewing conditions. However, it is difficult to replace the RGB devices with high cost multi-spectral devices since the latter have advanced only to the laboratory level. In the proposed method, the standard RGB values are converted into spectral information, then returned to RGB values for different viewing conditions. This process provides more accurate reproduction than the conventional forward process of the color reproduction. An experiment of psychophysical color matching was performed to evaluate the technique. The mixed chromatic adaptation model was applied to the method in the experiment, and the results showed the effectiveness of the proposed method.     

卡尔曼滤波-分光光度法同时分析长江和嘉陵江地表水中的微量铜、镉和锌

1-(2-吡啶偶氮)-2-萘酚(PAN)是一种用于测定微量金属离子浓度的显色试剂,利用PAN研究了这种显色剂与微量金属离子Cu2 ,Cd2 和Zn2 形成螯合物的分析条件,即与这三种金属离子形成螯合物的最大吸收光谱性质、pH值影响和螯合反应时间等,并结合卡尔曼滤波算法和可见光度计同时联机的定量测定技术,定量分析了实验室水样、长江和嘉陵江地表水样中微量Cu2 ,Cd2 和Zn2 金属离子的浓度。实验室三种金属离子的定量分析回收率在90.2%~106.2%之间,与长江、嘉陵江国控点例行监测数据的比较则表明:该方法的分析结果具有较好的可比性和可靠性。因此,该方法可以方便和直接应用于实际江河流域金属离子污染水样的定量分析。     

Room-Temperature Level Anticrossing and Cross-Relaxation Spectroscopy of Spin Color Centers in SiC Single Crystals and Nanostructures

A sharp variation of the near infrared photoluminescence intensity for spin-3/2 color centers in hexagonal (4H-, 6H-) and rhombic (15R-) SiC polytypes in the vicinity of level anticrossing (LAC) and cross-relaxation in an external magnetic field at room temperature are observed. This effect can be used for a purely all-optical sensing of the magnetic field with nanoscale spatial resolution. A distinctive feature of the LAC signal is a weak dependence on the magnetic field direction that allows monitoring of the LAC signals in the nonoriented systems, such as powder materials, without need to determine the nanocrystal orientation in the sensing measurements. Furthermore, an LAC-like signal is also observed for the spin color centers (NV centers) in diamond in low magnetic fields with only marginal dependence on the magnetic field direction. This effect is enabled to detect weak magnetic fields using nanodiamond samples in the form of disordered mixture. In addition, the optically detected magnetic resonance and LAC techniques are suggested to serve as a simple method to determine the local stress in nanodiamonds under ambient conditions.     

不同环境参数下CIECAM02的跨媒体颜色复现性能

为研究CIECAM02三种环境参数(dark,dim,average)在三种相应照明环境下的跨媒体颜色复现性能,基于记忆匹配和成对比较的心理物理学实验方法,在灯箱照明打印样本与Dark,Dim,Average三种不同环境照明条件下液晶显示器显示色样之间进行了跨媒体颜色复现实验。实验数据分析表明,采用dim环境参数在三种照明条件下都能达到较优的颜色复现性能,而dark和average参数性能与测试颜色的明度和彩度存在一定相关性,较暗色样在Dark条件下采用dark参数设置复现良好,但在Average实验条件下采用average参数设置时性能很差;对于较亮色样的复现,dark与average参数设置在其相应实验条件下的颜色复现性能无显著差异。     

Infrared thermography for condition monitoring – A review

Temperature is one of the most common indicators of the structural health of equipment and components. Faulty machineries, corroded electrical connections, damaged material components, etc., can cause abnormal temperature distribution. By now, infrared thermography (IRT) has become a matured and widely accepted condition monitoring tool where the temperature is measured in real time in a non-contact manner. IRT enables early detection of equipment flaws and faulty industrial processes under operating condition thereby, reducing system down time, catastrophic breakdown and maintenance cost. Last three decades witnessed a steady growth in the use of IRT as a condition monitoring technique in civil structures, electrical installations, machineries and equipment, material deformation under various loading conditions, corrosion damages and welding processes. IRT has also found its application in nuclear, aerospace, food, paper, wood and plastic industries. With the advent of newer generations of infrared camera, IRT is becoming a more accurate, reliable and cost effective technique. This review focuses on the advances of IRT as a non-contact and non-invasive condition monitoring tool for machineries, equipment and processes. Various conditions monitoring applications are discussed in details, along with some basics of IRT, experimental procedures and data analysis techniques. Sufficient background information is also provided for the beginners and non-experts for easy understanding of the subject.     

海洋水色水温扫描仪精确大气漫射透射比计算

海洋水色水温扫描仪(COCTS)是中国海洋水色系列卫星上的主遥感器,主要用于探测我国及全球部分海域的海洋水色和水温环境信息.大气漫射透射比计算是COCTS大气校正的必需过程,直接影响COCTS大气校正和水色信息反演的精度.提出了基于加倍法解大气-海洋耦合矢量辐射传输方程的大气漫射透射比精确计算方法,通过与SeaWiFS精确大气漫射透射比查找表计算结果的比较,结果表明计算相对误差小于1.5%,而当观测天顶角小于60°时,计算相对误差小于0.5%,可以用来生成COCTS的精确大气漫射透射比查找表.在此基础上,生成了专门针对COCTS的精确大气漫射透射比查找表.     

非标准光源在颜色测量中的差异性分析

不同光源因光谱功率分布差异,具有不同色温、显色指数,测色差异很大。D65标准光源最接近日光光色,是国际照明委员会(CIE)推荐测色标准光源。但其价格昂贵、工作条件苛刻且不易得,实际测色中常用非标准光源代替。为了研究非标准光源的测色差异,设计了一套溶液比色系统,分别采用高压脉冲氙灯、LED灯、卤钨灯作为光源,亚硝酸盐显色实验为基础,以色度学原理计算3种光源的测色差异。结果显示,氙灯、LED灯光谱分布较为均匀,色度坐标接近等能白光E(0.33, 0.33), 测色比较接近真实颜色,而卤钨灯测色误差较大。氙灯与LED灯在L*a*b*空间测色平均色差ΔE_ab在10 NBS以内,两者与卤钨灯测色平均色差ΔE_ab在20 NBS以上。     

EXPERIMENTAL VALIDATION OF A STRUCTURAL HEALTH MONITORING METHODOLOGY: PART II. NOVELTY DETECTION ON A GNAT AIRCRAFT

This paper concerns the second phase of an experimental validation programme for a structural health monitoring methodology based on novelty detection. This phase seeks to apply one of the methods considered in the first stage of the work on a more realistic structure, namely the wing of a Gnat aircraft, as opposed to the previously investigated laboratory structure. The novelty detection algorithm used is that of outlier analysis and damage is introduced by making several copies of an inspection panel, each with a different controlled fault. All of these faults were detectable, a single feature was highlighted which proved capable of separating all the fault conditions from the unfaulted.     

有源相控阵雷达状态监测与健康管理技术

状态监测和健康管理技术作为新一代测试与诊断技术,是装备自主式保障的核心系统之一,在保障武器装备战备完好性,提高作战效能,降低全寿命周期费用等方面具有重要作用;从有源相控阵雷达的状态监测与健康管理入手,构建了分层式健康管理系统框架,以作用距离和副瓣电平等指标进行信息融合和健康评估,实现了有源相控阵雷达的状态监测和健康管理。