Phase locked loop profilometry

An innovative technique for obtaining automatic three-dimensional shape information of a diffuse surface is presented. The technique is based on a new approach of phase measuring from a fringe pattern. The target to be studied is first modulated by projecting a linear grating onto its surface. The linear fringes are deformed according to the surface shape. Demodulation is carried out by determining the phase of these deformed fringes using a novel digital phase locked loop demodulation algorithm. The technique has the main advantage that the traditional phase unwrapping process is not required. The phase is determined continuously as the algorithm scans the two-dimensional fringe pattern. Owing to its sequential nature, this phase detection technique can be implemented using a special purpose video processor for phase determination at video rates, making it a very fast algorithm. The algorithm along with experimental results of real surface profiles are presented.     

Haar-Gaussian小波变换在边缘测量中的应用

应用Harr-Gaussian小波变换对图形图像的边缘进行频域分析，建立边缘测量的物理模型， 并用带宽匹配方法和远心测量光学系统，在大景深物体测量中获得准确的结果. 关键词： 小波变换 边缘测量 测不准原理 远心系统 图像识别 自动检测     

Quantifying larval infestation with an acoustical sensor array and cluster analysis of cross-correlation outputs

An automated, computer-based system was designed to quantify infestation of internally feeding larvae in a grain sample by obtaining data correlated with the location of sound sources. Information related to the relative arrival times of insect feeding sounds to an array of acoustic sensors is obtained despite the low signal to noise ratios and the differential distortion induced by sound propagation through the non-uniform grain medium to the different sensors. This is achieved by employing parallel acquisition of all sensor outputs and cross-correlation analyses of all adjacent sensor pairs in the vicinity of the sensor with the largest signal. The peak location times of the resulting cross-correlograms cluster together for multiple sounds produced by the same insect but otherwise are more broadly distributed. A cluster analysis algorithm was developed to group sounds with similar ‘fingerprints’ (i.e. patterns of peak locations across several cross-correlograms). Each sufficiently large group of matching sounds indicates the presence of an insect.     

Geometrical measurements of fibre-optic starter tubes using a novel optical technique

A novel optical technique is described for making geometrical measurements on silica starter tubes. The measurement takes place in an air medium and uses a collimated source and spatial filtering to image the set of transmitted rays onto a CCTV system. An analysis relates this line structure observed to the geometry of the starter tube.     

Decision theoretic analysis of pollutant emission monitoring procedures

A decision theoretic problem is considered which arises in the context of monitoring point sources of pollution: The management of an industrial plant may be authorized to release per unit time some amount of pollutants into the environment, for example air or water. An environmental agency may control, i.e. decide with the help of randomly sampled measurements, whether or not the real releases are larger than the permitted ones. The analysis of the problem of determining the best inspection procedure is performed with the help of a non-cooperative two-person game and can be constructed as follows: For a given value of the false alarm probability, only a zero-sum game has to be considered, where the probability of detecting illegal behavior is the payoff to the inspector. The solution of this game, i.e. the best inspection procedure, is then determined by use of the Neyman-Pearson Lemma.     

NIRS分析技术在饲料品质检测中的应用

简介近红外光谱（Near Infrared Spectroscopy,NIRS)分析技术的优点，原理和应用，并重点对其在饲料品质检测中的应用进行综述（引用文献共51篇）。     

抗疲劳类保健品中非法添加药物的拉曼检测法

本文采用拉曼光谱方法研究抗疲劳类保健品中非法添加化学药物的快速筛查方法。该方法结合拉曼光谱初筛、光谱叠加分析和增强拉曼光谱以获取样品的特征拉曼信息,通过分析样品和化学药物的拉曼信息的匹配程度,判断抗疲劳类保健品中是否非法添加了化学药物。采用这种方法对北京公安在市场上抽样送检的上百种保健品进行了测试,检测的准确性大于95%,这表明拉曼光谱方法可用于快速筛查抗疲劳类保健品中是否非法添加药物。     

Thermographic inspection of wind turbine rotor blade segment utilizing natural conditions as excitation source,Part II: The effect of climatic conditions on thermographic inspections – A long term outdoor experiment

The present study continues the work described in part I of this paper in evaluating a long-term-experiment, where a rotor blade segment of a wind turbine is exposed to the elements and thereby monitored with passive thermography. First, it is investigated whether subsurface features in rotor blades – mainly made of GFRP – can generally be detected with thermography from greater distances under favorable conditions. The suitability of the sun for acting as a heat source in applying active thermography has been tested in the previous study. In this study, the climatic influence on thermographic measurement is evaluated. It is demonstrated that there are favorable and unfavorable circumstances for imaging thermal contrasts which reflect inner structures and other subsurface features like potential defects. It turns out that solar radiation serves as a very effective heat source, but not at all times of day. Other environmental influences such as diurnal temperature variations also create temperature contrasts that permit conclusions on subsurface features. Particular scenarios are reconstructed with FEM-simulations in order to gain deeper insight into the driving mechanisms that produce the observed thermal contrasts. These investigations may help planning useful outdoor operations for inspecting rotor blades with thermography.     

Multispectral laser imaging for advanced food analysis

A hardware–software apparatus for food inspection capable of realizing multispectral NIR laser imaging at four different wavelengths is herein discussed. The system was designed to operate in a through-transmission configuration to detect the presence of unwanted foreign bodies inside samples, whether packed or unpacked. A modified Lock-In technique was employed to counterbalance the significant signal intensity attenuation due to transmission across the sample and to extract the multispectral information more efficiently. The NIR laser wavelengths used to acquire the multispectral images can be varied to deal with different materials and to focus on specific aspects. In the present work the wavelengths were selected after a preliminary analysis to enhance the image contrast between foreign bodies and food in the sample, thus identifying the location and nature of the defects. Experimental results obtained from several specimens, with and without packaging, are presented and the multispectral image processing as well as the achievable spatial resolution of the system are discussed.     

具有质量安全惩罚主导权零售商与供应商的食品安全检测决策

针对食品质量安全检测问题,建立了一个供应商与一个具有质量安全惩罚主导权零售商关于质量安全检测水平的优化模型,分析了他们各自独立与合作一体化模式下的质量安全检测水平决策,重点探讨了零售商对供应商的质量安全惩罚额对双方检测水平决策的影响.结果表明:当零售商对供应商的惩罚额较高时,供应商与零售商的质量安全检测水平都会随着惩罚额的增加而提高等主要结论.最后,为加强我国食品质量安全检测提供了对策.