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cross-correlation algorithm-Based Optimization of Aliasing Signals for Inductive Debris Sensors

SENSORS 2020年第20期20卷 5949.-5949.页

作者： Wang, Xingjian Sun, Hanyu Wang, Shaoping Huang, Wenhao Beihang Univ Sch Automat Sci & Elect Engn Beijing 100191 Peoples R China Beihang Univ Beijing Adv Innovat Ctr Big Data Based Precis Med Beijing 100191 Peoples R China Beihang Univ Ningbo Inst Technol Ningbo 315800 Peoples R China Beihang Univ Sci & Technol Aircraft Control Lab Beijing 100191 Peoples R China Chinese Acad Sci Shenzhen Inst Adv Technol Shenzhen 518055 Peoples R China

An inductive debris sensor can monitor a mechanical system's debris in real time. The measuring accuracy is significantly affected by the signal aliasing issue happening in the monitoring process. In this study, a mathematical model was built to explain two debris particles' aliasing behavior. Then, a cross-correlation-based method was proposed to deal with this aliasing. Afterwards, taking advantage of the processed signal along with the original signal, an optimization strategy was proposed to make the evaluation of the aliasing debris more accurate than that merely using initial signals. Compared to other methods, the proposed method has fewer limitations in practical applications. The simulation and experimental results also verified the advantage of the proposed method.

关键词： inductive debris sensor signal aliasing cross-correlation algorithm optimization strategy

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Modulated optical signal detection based on cross-correlation algorithm

Modulated optical signal detection based on cross-correlatio...

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Conference on AOPC - Advanced Laser Technology and Applications

作者： Zeng, Ke Han, Junfeng Wang, Haitao Wang, Chen Xie, Xiaoping Univ Chinese Acad Sci Beijing 100049 Peoples R China Chinese Acad Sci Xian Inst Opt & Precis Mech Xian 710119 Peoples R China

ISBN: (数字)9781510649965

ISBN: (纸本)9781510649965;9781510649958

With the development of the information age, the transmission rate and transmission capacity of information continue to increase. As a wireless communication method to achieve high bit rate communication, space laser communication plays an increasingly obvious role in global communications. In the current space laser communication system, the optical communication terminal uses a detector to detect the position of the received optical signal, and then the servo mechanism on it performs facula tracking. However, when a four-quadrant detector (4QD) is used to detect optical signal, the received optical signal generally contains three main types of noise, which are background radiation noise, shot noise and thermal noise. These three kinds of noise can be equivalent to Gaussian white noise. In this paper, a single-frequency cosine signal is used to modulate the intensity of the optical signal received by the 4QD, and then the modulated optical signal is detected by a spectrum analysis method based on the cross-correlation algorithm. This method reduces the relative error of the spectral line amplitude when the SNR is -5dB from 2.23% to 0.88%, and reduces the relative error of the spectral line amplitude when the SNR is -20dB from 17.6% to 5.49%. Therefore, this method can well suppress Gaussian white noise and improve the detection accuracy of modulated optical signal under extremely low SNR conditions.

关键词： Space laser communication Modulated optical signal cross-correlation algorithm Extremely low SNR

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Valley-positioning-assisted discrete cross-correlation algorithm for fast cavity length interrogation of fiber-optic Fabry-Perot sensors

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MEASUREMENT 2022年 198卷

作者： Kang, Jiawen Chen, Haibin Zhang, Xiongxing Zhang, Junying Guo, Zilong Wang, Wei Xian Technol Univ Sch Optoelect Engn Xian 710021 Peoples R China Xian Technol Univ Shaanxi Prov Key Lab Photoelect Measurement & Ins Xian 710021 Peoples R China

This study proposes a valley-positioning-assisted discrete cross-correlation algorithm for the fast cavity length interrogation of fiber-optic Fabry-Perot (FP) sensors. Because the number of template cavity lengths that require to be cross-correlated with the spectral function of the FP sensor is dramatically decreased by considering the interference order and discretization of the template function, the computation amount can be effectively reduced without sacrificing the interrogating resolution. The feasibility and performance of the proposed algorithm were successfully verified through simulations and experiments. In the cavity length range of 20-130 mu m, fiber-optic FP sensors were successfully interrogated with high performance. The maximum error is 3.97 nm, and the resolution reaches a value of 2.62 nm.

关键词： Fiber-optic sensor Fabry-Perot cavity Valley-positioning method cross-correlation algorithm

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Measurement of transverse wind speed in atmospheric turbulence by cross-correlation algorithm

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OPTICAL ENGINEERING 2022年第6期61卷 066110-066110页

作者： Wu, Jiali Ke, Xizheng Feng, Xiaorong Xian Univ Technol Fac Automat & Informat Engn Xian Peoples R China Shaanxi Univ Technol Fac Phys & Telecommun Engn Hanzhong Peoples R China Shaanxi Civil Mil Integrat Key Lab Intelligence C Xian Peoples R China

Owing to the transverse wind, a laser beam drifts when transmitting in an atmospheric channel. The moving speed of the light spot image at the receiving end was deduced using cross-correlation algorithm. By establishing experiments with communication distances of 1.3 km and 100 km, the relationship between the transverse wind and the moving speed of the spot particle image on the optical transmission path was obtained. The results show that the correlation coefficients between the transverse wind and spot particle image moving speed are 0.92 and 0.83, respectively, which proves the feasibility of using the cross-correlation algorithm to obtain the transverse wind speed in atmospheric turbulence. And from this approach, the transverse wind speed and the wind vector moving image on the transmission path can be analyzed easily. (C) 2022 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： atmospheric turbulence transverse wind cross-correlation algorithm

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Self-Identification and Balancing for AMB-Rotor System of Turbomolecular Pumps

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IEEE-ASME TRANSACTIONS ON MECHATRONICS 2024年 1-10页

作者： Yin, Yifan Liu, Ximing Wang, Kun Zheng, Shiqiang Beihang Univ Sch Instrumentat & Optoelect Engn Beijing 100191 Peoples R China Beihang Univ Sch Automat Sci & Elect Engn Beijing 100191 Peoples R China

The rotor unbalance of the magnetic levitated turbomolecular pump (MLTMP) can lead to undesirable rotor synchronous vibration, and thus seriously affect the instrumentation precision in the ultra-high vacuum condition. The accurate identification and elimination of rotor unbalance is the primary issue for system stable operation at high speeds. This article proposes a method for rotor unbalance self-identification without using external information, and designs a model parameter correction procedure to improve the rotor balancing precision. First, the complex coefficient method is utilized to establish the rotor dynamic model under the regular controller, and the numerical equivalence between the correction mass centrifugal force and magnetic bearings force is used to obtain the rotor unbalance. Then, the rotor synchronous responses based on rotor radial displacement and bearing control currents are extracted through the cross-correlation algorithm. To further improve the rotor unbalance measurement accuracy, the stiffness coefficient values are also corrected by introducing virtual trial weights. Finally, the experimental results conducted on a MLTMP prototype verify the effectiveness of the proposed method in the self-identification of rotor unbalance.

关键词： Rotors Magnetic levitation Force Accuracy Vibrations Coils Mechatronics Active magnetic bearing (AMB) cross-correlation algorithm field dynamic balancing stiffness coefficients correction turbomolecular pumps

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cross-correlation algorithm optimization of ultrasonic level meter

Cross-correlation algorithm optimization of ultrasonic level...

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2014 International Conference on Industrial Electronics and Engineering (ICIEE 2014)

作者： Hui Xu Lin Li Xinsheng Che School of Information Science & Engineering Shenyang University of Technology

The threshold value comparative method is generally used in the measurement of delay time in the ultrasonic pulse echo method. The measurement error is large since the threshold method is easy to turn error with the interference. So in this paper, cross-correlation algorithm is used to calculate the delay time. The overlap retaining method and improved real sequence fast Fourier transform algorithm are used to calculate the cross-correlation of the transmitted sequence and received sequence, so the calculated amount and measurement error are reduced, and the accuracy of the ultrasonic level meter is improved.

关键词： cross-correlation algorithm overlap retaining method fast Fourier transform ultrasonic level meter

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Study on the co-phasing simulation and experimental of segmented mirror based on broadband light

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JOURNAL OF MODERN OPTICS 2024年第1-3期71卷 42-51页

作者： Li, Bin Liu, Yinling Yang, Akun Chen, Nan Wu, Jian Chen, Mo East China Jiao Tong Univ Intelligent Electromech Equipment Innovat Res Inst Nanchang Peoples R China Chinese Acad Sci Inst Opt & Elect Chengdu 610209 Peoples R China

At present, the co-phasing detection algorithms for segmented mirrors struggle to balance the measurement range and accuracy. This paper proposes a coarse co-phasing measurement method using the incoherent properties of a broadband (400-800 nm) light source combined with the incoherence of two semicircular diffraction patterns of visible light as a template to detect the piston error, and a narrowband algorithm for fine co-phasing measurement. The diversity factors between template patterns and actual diffraction patterns can be calculated by the cross-correlation algorithm. This proposed method addresses long measurement time caused by low target flow rate and is characterized by wide measurement range, high precision and high energy utilization. The method is theoretically researched and simulated and an experimental system which was constructed to verify the effectiveness of this method achieves 15 nm detection accuracy, and the measurement range using the proposed method can match the measurement range of the actuator.

关键词： Segmented mirrors cross-correlation algorithm phase detection broadband light

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Seismic Facies-Guided High-Precision Geological Anomaly Identification Method and Application

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2024年 62卷 1页

作者： Duan, Jing Zhang, Gulan You, Jiachun Hu, Guanghui Luo, Yiliang Ran, Shiyun Zhong, Qihong Cao, Caijun Tang, Wenjie Liang, Chenxi Southwest Petr Univ Sch Geosci & Technol Chengdu 610500 Peoples R China Southwest Petr Univ State Key Lab Oil & Gas Reservoir Geol & Exploitat Chengdu 610500 Peoples R China Chengdu Univ Technol Coll Geophys Chengdu 610059 Peoples R China Sinopec Inst Geophys Technol Nanjing 211103 Peoples R China

The popular geological anomaly (such as fault, river course, cave, and crack) identification methods, such as coherence cube, semblance, likelihood, and others, usually can achieve higher precision geological anomaly identification results when applied to the target horizon flattened seismic data, comparing to their counterparts using the target horizon-unflattened seismic data. However, these methods still face great challenges in achieving high-precision geological anomaly identification results, due to the complexity of the geological structure (or the seismic data) and the horizon tracking accuracy of the target horizon. To minimize the impact of the complexity of geological structure and the horizon tracking accuracy of the target horizon in geological anomaly identification, thereby obtaining high-precision geological anomaly identification results and providing precise labels for deep-learning-based geological anomaly identification methods, we propose a seismic facies-guided high-precision geological anomaly identification method (FHGI), basing on the concept of seismic facies and the cross-correlation algorithm. FHGI contains the flowchart of FHGI, and the seismic facies-guided trace-by-trace high-precision geological anomaly identification factor calculation (FTGC);in which FTGC consists of the target horizon-based seismic data flattening (THF), the seismic facies-guided target trace 2-D subseismic dataset generation (FTG), the cross-correlation algorithm-based target horizon further flattening (CFA), and the cross-correlation coefficient-based high-precision geological anomaly identification factor calculation (CGC). The THF aims to reduce the impact of the complexity of the geological structure and provide the input 3-D seismic data for the FTG. FTG aims to automatically generate the 2-D subseismic dataset corresponding to the target trace, thereby further reducing the impact of the complexity of the geological structure and providing the input 2-D subse

关键词： Geology Three-dimensional displays Coherence Complexity theory Fault diagnosis Accuracy Target tracking cross-correlation algorithm geological anomaly identification seismic facies-guided

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DSM-Based Precise Pointing Angle Deviation Measurement Method for Beaconless Free Space Optical Communication

IEEE PHOTONICS JOURNAL

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IEEE PHOTONICS JOURNAL 2023年第6期15卷 1页

作者： Ao, Xueyuan Zou, Yansheng Zou, Yang Fan, Qirun Dai, Xiaoxiao Liu, Chen Yang, Qi Liu, Deming Huazhong Univ Sci & Technol Sch Opt & Elect Informat Wuhan 430074 Peoples R China Univ Sci & Technol Shenzhen Res Inst Huazhong Shenzhen 518000 Peoples R China

In free space optical (FSO) communication, acquisition, tracking and pointing (ATP) is the key technology to maintain a high-quality FSOlink. Specifically, the detection of pointing angle deviation greatly affects the performance of ATP, especially under weak receiving power. However, the separated beacon laser beam commonly used in ATP will increase the structural complexity of the terminal such as the size, weight, and power. It is unwanted in some limited applications such as satellite. To improve the pointing accuracy with weak signal in beaconless FSO communication, we propose a delta-sigma enabled beaconless cross-correlation (CCR) method with four-quadrant detectors. In the proposed method, a low-frequency sine analog signal for CCR calculation is modulated into a 1-bit digital signal by delta-sigma modulation and then inserted into the communication data as a training sequence. The root means square error (RMSE) of the pointing angle deviation measurement is 14.17 mu rad with the incident optical power of-40 dBm. Compared with the direct intensity method, of which RMSE is 67.61 mu rad, the proposed method can effectively improve the pointing accuracy with weak power without a beacon laser in FSO communication.

关键词： Four-quadrant detector pointing angle deviation measurement beaconless free space optical communication cross-correlation algorithm delta-sigma modulation

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An Experimental Study on Velocity Characteristics of the Slug Flow in Gas-Liquid Pipe Flows

An Experimental Study on Velocity Characteristics of the Slu...

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International Conference on Energy Engineering, ICEE 2023

作者： Xu, Siyuan Li, Hua Lin, Jingde Liu, Yinhua Zhao, Peihua Zhong, Xingfu Zhang, Jun Engineering Technology Research Institute PetroChina Coalbed Methane Company Limited Xi’an 710003 China Institute of Mechanics Chinese Academy of Sciences Beijing100190 China China United Coalbed Methane National Engineering Research Center Co. Ltd. Beijing100095 China PetroChina Coalbed Methane Company Limited Beijing100028 China

ISBN: (纸本)9789819771455

Slug flow is commonly encountered in industrial flows, its characteristics like strong intermittence and high pressure drop are usually harmful to the industrial process and facilities. Slug flow has more characteristic parameters than other flow regimes, and the fluctuation of these parameters makes it more difficult for their study. This paper investigates the velocity characteristics of slug flow via the fast electrical impedance tomography technique. First, the images of a series of gas-liquid slug flows in the vertical upward pipe are collected and reconstructed, then the velocity distributions of different regions are calculated by the cross-correlation algorithm. After that, the different regions in slug flow are distinguished based on image analysis, and the leading-edge velocity of Taylor bubbles is acquired. Finally, the velocity characteristics are analyzed and compared with the calculated result of the theoretical model and empirical formula. This study indicates that the fast electrical impedance tomography technique is capable of reconstructing the flow structure images, and acquiring the key velocity parameters in slug flow, which can be used to verify and improve the relative theoretical models and empirical formulas, thus is beneficial for improving the precision of the slug flow model. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： cross-correlation algorithm Electrical impedance tomography Gas-liquid two-phase pipe flow Slug flow Velocity distribution

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