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2nd International Conference on Multimedia and Signal Processing (CMSP 2012)

作者： Chen, Min Wang, Hongrong Fujian Univ Technol Dept Comp & Informat Sci Fuzhou Peoples R China

ISBN: (纸本)9783642352850

The application of cross-correlation algorithm should be preceded by the calibration system validating the precision and accuracy of the algorithm. Selected adjacent two images from the video stream of the moving target, and calculate the displacement of the moving target, and then the vector information can be obtained according to the time interval set in the video capture rate. cross-correlation algorithm in order to reduce computation, the image on the equivalent land is divided into several regions, the sub-regions of the same location is calculated. The selection of the size of the sub-regions will affect the accuracy of measurement results, so the image calibration system using a variety of images to find the association between the size of the sub-regions and the intensity of the images. This will reduce the generation of error, and founded a basement for the subsequent processing. Because the selection of the sub-regions size will affect the accuracy of measurement results, the image calibration system testing images with variety intensities to find the association between the size of the sub-regions and the image intensities. This will reduce the generation of error, and lay a good foundation for the subsequent processing. The development of the image calibration system is developed under Windows, using C/C++ programming languages, and the openCV open source image library.

关键词： calibration system cross-correlation algorithm sub-region openCV

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Non destructive testing thickness measurement by laser ultrasound under high temperature

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OPTIK 2018年 172卷 1140-1154页

作者： Li, Suyuan Wang, Haitao Guo, Ruipeng Zhao, Jiyuan Zheng, Kai Xu, Jun Chen, Shuai Jiang, Yi Nanjing Univ Aeronaut & Astronaut Coll Automat Engn Nanjing 211106 Jiangsu Peoples R China Xi An Jiao Tong Univ Collaborat Innovat Ctr High End Mfg Equipment Xian 710049 Shaanxi Peoples R China Special Equipment Safety Supervis Inspect Inst Ji Nanjing 210036 Jiangsu Peoples R China

Corrosion is one of the main failure modes of pressure vessel, of which the inspection is mainly conducted through the thickness measurement. Due to the limitation of current testing methods, most of the equipment needs to be shut down and maintained. In this paper, a non-contact thickness measurement based on laser ultrasound is introduced, which can realize the on-line thickness detection under high temperature. Based on the theory of laser ultrasound, effects of high temperature on the longitudinal wave are discussed. The simulation signals of models with different thickness at different temperatures are obtained, and the results show that the velocity of longitudinal wave will decrease with the increase of temperature. Ultrasonic wave is excited on one side of material and the interferometer is used to collect ultrasonic wave on the same side in the experiment. Since the noise-signal ratio of the original signal is low, the collected raw signal is processed by wavelet denoising. In order to obtain the temporal information of longitudinal wave, three spline interpolation and cross-correlation algorithm are used to process the de-noised signal. The temporal information of longitudinal wave can be obtained from the processed signal, and the thickness of the material can be calculated by using the time interval between different longitudinal waves. The results of this study provide a good theoretical and experimental basis for the industrial application of petrochemical industry.

关键词： Corrosion Laser ultrasound Wavelet denoising Three spline interpolation cross-correlation algorithm Thickness

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A Fiber-Optic Displacement Sensor Based on High-Precision Differential Phase Measurement

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2018年第18期36卷 4046-4050页

作者： Chen, Ke Guo, Min Yang, Yang Liu, Kang Cai, Wanjin Yu, Qingxu Dalian Univ Technol Sch Optoelect Engn & Instrumentat Sci Dalian 116023 Peoples R China

A fiber-optic displacement sensing scheme based on high-precision detection of differential phase is proposed, with advantages of simple structure, low cost, high precision, large dynamic range, polarization independent, and remote sensing ability. The designed displacement sensor is composed of a sensing fiber, a reference fiber, a Fabry-Perot laser diode, five couplers, two photodiodes and a signal processing circuit. The reference fiber is used for temperature compensation. The optical path difference (OPD) between the two fibers varies with the stretch of the sensing fiber. By high-frequency sinusoidal modulation of the laser source, the OPD can be converted to the differential phase between the reflected lights from the endfaces of the two fibers. The differential phase is detected by cross-correlation method. Experimental results show that, the resolution of the static displacement measurement has been achieved to be 1.4 mu m. In addition, the dynamic range is estimated to be 2.66 m. Furthermore, the designed sensor shows the capability of dynamic displacement measurement.

关键词： cross-correlation algorithm differential phase displacement sensor fiber-optic sensing

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Method of detecting pipeline leakage location based on multiresolution analysis

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JOURNAL OF ENGINEERING-JOE 2019年第15期2019卷 552-554页

作者： Zhang, QingChun Liu, Bei Qiu, Yu Zhang, Xi Huaiyin Inst Technol Huaian Jiangsu Peoples R China

Aiming at the problem of low precision of traditional pipeline leakage detection method, a high-precision pipeline leakage detection method based on acoustic signal is proposed, which combines multiresolution analysis of wavelet transform and cross-correlation algorithm of signal processing. As of the large amount of background noise in the pipeline, it is necessary to filter the high-frequency noise by wavelet transform. In order to improve the accuracy of localisation, the noise is checked at different scales and the noise is filtered at lower scales to retain more details of the acoustic signal leakage. Combined with cross-correlation function, the location of pipeline leakage location is repeatedly positioned to improve the accuracy of positioning.

关键词： wavelet transforms correlation methods leak detection pipelines acoustic signal processing condition monitoring mechanical engineering computing high-precision pipeline leakage detection method cross-correlation algorithm acoustic signal processing wavelet transform noise filter

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Investigation of Micro-volume Viscosity with Janus Microbeads Based on Rotational Brownian Motion

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SENSORS 2019年第5期19卷 1217-1217页

作者： Chen, Chun-Jui Chen, Wei-Long Pham Hong Phong Chuang, Han-Sheng Natl Cheng Kung Univ Dept Biomed Engn Tainan 701 Taiwan Vietnam Acad Sci & Technol Inst Chem Hanoi 1000 Vietnam Grad Univ Sci & Technol Vietnam Acad Sci & Technol Hanoi 1000 Vietnam Natl Cheng Kung Univ Med Device Innovat Ctr Tainan 701 Taiwan

Viscosity is an important property of liquids. A viscosity change of aqueous substances that deviates from their normal levels usually implies a compromise in quality due to degradation or microorganism proliferation. Monitoring of macro-scale viscosity can be simply realized by various conventional tools, such as rotational viscometers, capillary tubes, falling bodies, and so forth. Nevertheless, today, micro-volume viscosity measurement remains a challenging endeavor, resulting in rare, expensive, or difficult-to-obtain samples not very well studied. For this reason, a novel technique for micro-viscosity based on rotational Brownian motion is presented in this paper. Janus microbeads were made by coating fluorescent polystyrene beads with gold film. Taking advantage of the bead configuration of half gold/half fluorescence, the rotational Brownian signal was expressed in terms of blinking fluorescent intensity. The characteristic correlation time was derived from the blinking intensity of trace amounts of a selected medium over a certain time period, and results were correlated with viscosity. Given a volume of only 2 L for each measurement, calibration of a series of glycerol-water mixtures (100%-1% (v/v) water content) yielded good agreement with the expected viscosity predictions over the range of 0.8-574.8 cP. Five common oil products, including lubricant oil, baby oil, food oil, olive oil, and motor oil, were further investigated to demonstrate the feasibility and practicability of the proposed technique. Data measured by the rotational Brownian motion-based diffusometer were comparable with those measured by a commercial rotational viscometer. The method also explicitly showed viscosity degradation after the oils were heated at a high temperature of over 100 degrees C for 10 min. Evaluation proved the proposed Janus microbead-enabled rotational diffusometric technique to be a promising approach for rapid and micro-scale viscosity measurement.

关键词： rotational Brownian motion Janus microbead micro-volume viscosity cross-correlation algorithm

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A cross correlation method for chemical profiles in minerals, with an application to zircons of the Kilgore Tuff (USA)

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CONTRIBUTIONS TO MINERALOGY AND PETROLOGY 2018年第3期173卷 23-23页

作者： Probst, L. C. Sheldrake, T. E. Gander, M. J. Wallace, G. Simpson, G. Caricchi, L. Univ Geneva Dept Earth Sci 13 Rue Maraichers CH-1205 Geneva Switzerland Univ Geneva Sect Math 4 Rue Lievre CH-1205 Geneva Switzerland Pacific Groundwater Grp Eastlake Ave E 2377 Seattle WA USA

Magmatic crystals are characterised by chemical zonation patterns that reflect the thermal and chemical conditions within magma reservoirs in which they grew. Crystals that exhibit similar patterns of zonation are often interpreted to have experienced similar conditions of growth. These patterns of zonation may represent continuous processes such as cooling, or more instantaneous events such as magma injection, and provide an insight into the structure and evolution of a magmatic system, both temporally and spatially. We have developed an algorithm that is objectively able to quantify the similarity within and between suites of magmatic crystals from different samples. Significantly, the algorithm is able to identify correlation that occurs between the interiors of two crystals, but does not extend to the rim, which provides an opportunity to understand the long-term evolution of magmatic systems. We develop and explain the mathematical basis for our algorithm and introduce its application using cathodoluminescence images of zircons from the Kilgore Tuff (USA). The results allow us to correlate samples from two different outcrops that are found over 80 km apart.

关键词： cross-correlation algorithm Chemical zonation Crystal Magma reservoirs Volcano Caldera eruption

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Distributed feedback fiber laser for sub-nanostrain-resolution static strain measurement by use of swept beat-frequency demodulation 5

Distributed feedback fiber laser for sub-nanostrain-resoluti...

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5th Asia-Pacific Optical Sensors Conference (APOS)

作者： Huang, Wenzhu Zhang, Wentao Li, Fang Chinese Acad Sci Inst Semicond Optoelect Syst Lab Beijing 100083 Peoples R China

ISBN: (纸本)9781628418651

Fiber laser has the advantages of ultra-narrow linewidth, low phase and intensity noise, which is beneficial for ultra-high-resolution strain sensing. This paper presents a novel demodulation technique for sub-nanostrain-resolution static strain measurement based on two distributed feedback fiber lasers (DFB FLs). A commercial PZT-tunable laser is used to interrogate the DFB FLs and get the periodic frequency-difference characteristics (two linear chrip signals) by swept beat-frequency principle. Two polarization controllers are used for adjusting the polarization direction of DFB FLs. And one of the two DFB FLs is used for temperature compensation and eliminating the frequency shift influence of the commercial laser. Static strain is demodulated by calculating the difference of the direct current (DC) components of the two swept beat-frequency signals. A static-strain resolution of 0.88 n epsilon is obtained in the laboratory test.

关键词： fiber laser static strain beat frequency cross-correlation algorithm

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Remove the time base drift of sampling oscilloscope 12

Remove the time base drift of sampling oscilloscope

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12th IEEE International Conference on Electronic Measurement and Instruments (ICEMI)

作者： Zhu Jiangmiao Yang Jie Miao Jingyuan Beijing Univ Technol Coll Elect Informat & Control Engn Beijing 100124 Peoples R China Natl Inst Metrol Beijing 100013 Peoples R China

ISBN: (纸本)9781479970711

The time base drill is a key factor that influences the sampling oscilloscope to measure the high speed pulse signal precisely, so time base drift must he removed as far as possible. cross-correlation algorithm is an alternative method to remove time base drift effectively. First, this paper does computer simulation, then use the algorithm to do research on the original data that is collected when establishing national pulse parameters primary standard. Both the results of simulation and the research show that the cross-correlation algorithm can remove the time drift effectively

关键词： time base drift sampling oscilloscope pulse signal cross-correlation algorithm

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Remove the time base drift of sampling oscilloscope

Remove the time base drift of sampling oscilloscope

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2015 IEEE 12th International Conference on Electronic Measurement & Instruments

作者： Zhu Jiangmiao Yang Jie Miao Jingyuan College of Electronic Information & Control Engineering of Beijing University of Technology National Institute of Metrology

The time base drift is a key factor that influences the sampling oscilloscope to measure the high speed pulse signal precisely, so time base drift must be removed as far as possible. cross-correlation algorithm is an alternative method to remove time base drift effectively. First, this paper does computer simulation, then use the algorithm to do research on the original data that is collected when establishing national pulse parameters primary standard. Both the results of simulation and the research show that the cross-correlation algorithm can remove the time drift effectively.

关键词： time base drift sampling oscilloscope pulse signal cross-correlation algorithm

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A high resolution laser ranging system based on time-correlated single-photon counting technology

A high resolution laser ranging system based on time-correla...

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International Symposium on Optoelectronic Technology and Application (IPTA) - Laser and Optical Measurement Technology and Fiber Optic Sensors

作者： Yang, Yixin Wang, Huanqin Huang, Zhe Cao, Yangyang Gui, Huaqiao Univ Sci & Technol China Dept Automat 96 Jin Zhai Rd Hefei 230026 Anhui Peoples R China

ISBN: (纸本)9781628413830

Laser ranging has become an important method for both distance measurements and acquisition of three-dimensional (3D) images. In this paper, a laser ranging system based on Time-Correlated Single-Photon Counting technology (TCSPC) is developed. A Geiger-mode avalanche photodiode (G-APD), which has the ability of detecting single-photon events, is used to capture the weak light scattered from the long-range target. In order to improve the ranging resolution of TCSPC based measurement system, a high repetition frequency of sub-nanosecond narrow pulse generator circuit based on the avalanche effect of RF-BJT is designed and applied as the light source. Moreover, some optimized optical light designs have been done to improve the system signal to noise rate (SNR), including using a special aspherical lens as projecting lens, adopting a telephoto camera lens with small view angle and short depth of field before detector. Experimental tests for evaluation of the laser raging system performance are described. As a means of echo signal analysis, three different algorithms have been introduced, in which the cross-correlation algorithm was demonstrated to be the most effective algorithm to determining the round trip time to a target, even based on histograms with a significant amount of background noise photons. It was found that centimeter ranging resolution can be achieved thanks to the use of Time-to-Digital Converter (TDC) with picosecond resolution and the cross-correlation algorithm. The proposed laser ranging system has advantages of high range resolution, short response time and simple structure, which was potential applications for 3D object recognition, computer vision, reverse engineering and virtual reality.

关键词： Laser ranging time-of-flight TCSPC cross-correlation algorithm

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