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Calibration of Coherent optical Fiber Bundle with Lcd Screen for Deformation measurements

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SSRN 2022年

作者： Tu, Han Zhu, Canyu Gao, Zeren Bai, Chuanbiao Lan, Shihai Zhang, Qingchuan CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics University of Science and Technology of China Hefei230027 China Shenzhen Key Laboratory of Intelligent Optical Measurement and Detection College of Physics and Optoelectronic Engineering Shenzhen University 3688 Nanhai Avenue Shenzhen518060 China

Owning to its flexibility, high temperature resistance, and freedom from electromagnetic interference, coherent optical fiber bundle (COFB) is widely used in special imaging applications. However, limited by the manufacturing process, the fiber arrangement of COFB is prone to misalignment, resulting in imaging distortions that are not easily corrected. This limits the application of COFB in the field of optical measurement, making it difficult to meet the requirements of high-precision deformation measurement. To effectively calibrate the misalignment distortion and recover the original image information, this study proposes an easy-to-implement and highly accurate misalignment distortion calibration method. The LCD screen was used as the calibration reference to display a pre-designed regular arrangement pattern. The mapping relationship between the fiber output and the screen display information was confirmed using a correlation algorithm. The proposed method requires only 36 images to achieve misalignment calibration for 450×450 fibers. The image reconstruction results show that the proposed method can not only achieve global misalignment calibration, but also successfully eliminate honeycomb artifacts, thus enhancing the accuracy and practicality of COFB for deformation measurement. In addition, a COFB-based digital image correlation (DIC) system was established and a set of typical DIC experiments were implemented. The experimental results show that the proposed calibration method can significantly improve the deformation measurement accuracy of the COFB-based DIC system, and the accuracy of the two-dimensional (2D) displacement field measurement result is improved from 0.50 pixels to 0.03 pixels. © 2022, The Authors. All rights reserved.

关键词： Calibration

On-Site Dynamic Deformation measurements Based on Enhanced Temporal Speckle Pattern Interferometry

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SSRN 2024年

作者： Zhang, Ruyue Miao, Hong Xu, Jingchao Lai, Lizhao Hu, Jicen Fu, Yu CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics University of Science and Technology of China Anhui Hefei230027 China Shenzhen Key Laboratory of Intelligent Optical Measurement and Detection College of Physics and Optoelectronic Engineering Shenzhen University 3688 Nanhai Avenue Shenzhen518060 China

In this paper, a dynamic deformation measurement method based on enhanced temporal speckle pattern interferometry suitable for on-site measurements is proposed. An improved dynamic phase extraction algorithm is used to obtain phases that account for both ground vibrations and object deformations. In this algorithm, the impact of noise and speckle decorrelation is reduced through data preprocessing, and the phase extraction is achieved through a Hilbert transform and a two-stage, least-squares method. The deformations are obtained by separating the vibrations and deformations through a synchronous measurement system that combines laser Doppler vibrometers with a high-speed camera. The effectiveness of the method for dynamic deformation measurements under micron-level vibrations is verified by experiments. © 2024, The Authors. All rights reserved.

关键词： Speckle

A Simple Method for Laser Welding Depth Determination Using optical Coherence Tomography

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SSRN 2023年

作者： Xie, Guanming Wang, Sanhong Zhang, Yueqiang Hu, Biao Fu, Yu Yu, Qifeng Li, You Institute of Intelligent Optical Measurement and Detection Shenzhen University Shenzhen518060 China College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen518060 China Shenzhen University China National Key Laboratory of Human Factors Engineering China Astronaut Research and Training Center Beijing100094 China

optical coherence tomography (OCT) provides a direct measurement of welding depth during laser deep-penetration welding and shows high achievable accuracy in continuous monitoring. Statistical evaluation approach accurately extracts the welding depth from raw OCT-data but suffers from complexity in noise removal. In this work, a laser welding depth measuring system based on spectral-domain OCT (SD-OCT) is built and a simple method coupled DBSCAN and percentile filter is proposed. The noise of the raw OCT-data are effectively detected by DBSCAN and percentile filter is then applied to the cleaned OCT-data to extract the welding depth. By comparing the welding depth determined by the proposed method and the actual weld depth of the longitudinal cross section, an average error of less than 5% is obtained. The laser welding depth can be simply achieved by OCT with high-precision. © 2023, The Authors. All rights reserved.

关键词： optical tomography

An Efficient Method Coupled Dbscan and Percentile Filter for Laser Welding Depth Determination Using optical Coherence Tomography

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SSRN 2023年

作者： Xie, Guanming Wang, Sanhong Zhang, Yueqiang Hu, Biao Fu, Yu Yu, Qifeng Li, You Institute of Intelligent Optical Measurement and Detection Shenzhen University Shenzhen518060 China College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen518060 China Shenzhen Sincevision Technology Co. Ltd. Shenzhen518055 China National Key Laboratory of Human Factors Engineering China Astronaut Research and Training Center Beijing100094 China

optical coherence tomography (OCT) provides a direct welding depth measurement during laser welding and shows high achievable accuracy in continuous monitoring. Statistical evaluation approach accurately extracts the welding depth from OCT-data but suffers from complexity in noise removal. In this paper, an efficient method coupled DBSCAN (Density-Based Spatial Clustering of Application with noise) and percentile filter for laser welding depth determination is proposed. The noise of the OCT-data are viewed as outliers and detected by DBSCAN. After eliminating the noise, the percentile filter is used to extract the welding depth. By comparing the welding depth determined by this approach and the actual weld depth of longitudinal cross section, an average error of less than 5% is obtained. The precise laser welding depth can be efficiently achieved by the method. © 2023, The Authors. All rights reserved.

关键词： Laser beam welding

High-precision whispering gallery microsensors with ergodic spectra empowered by machine learning

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Photonics Research 2022年第10期10卷 2343-2348页

作者： BING DUAN HANYING ZOU JIN-HUI CHEN CHUN HUI MA XINGYUN ZHAO XIAOLONG ZHENG CHUAN WANG LIANG LIU DAQUAN YANG State Key Laboratory of Information Photonics and Optical Communications School of Information and Communication EngineeringBeijing University of Posts and TelecommunicationsBeijing 100876China Beijing Key Laboratory of Intelligent Telecommunication Software and Multimedia Beijing University of Posts and TelecommunicationsBeijing 100876China Institute of Electromagnetics and Acoustics and Fujian Provincial Key Laboratory of Electromagnetic Wave Science and Detection Technology Xiamen UniversityXiamen 361005China Shenzhen Research Institute of Xiamen University Shenzhen 518000China School of Artificial Intelligence Beijing Normal UniversityBeijing 100875China

Whispering gallery mode(WGM)microcavities provide increasing opportunities for precision measurement due to their ultrahigh sensitivity,compact size,and fast ***,the conventional WGM sensors rely on monitoring the changes of a single mode,and the abundant sensing information in WGM transmission spectra has not been fully ***,empowered by machine learning(ML),we propose and demonstrate an ergodic spectra sensing method in an optofluidic microcavity for high-precision pressure *** developed ML method realizes the analysis of the full features of optical *** prediction accuracy of 99.97%is obtained with the average error as low as 0.32 kPa in the pressure range of 100 kPa via the training and testing *** further achieve the real-time readout of arbitrary unknown pressure within the range of measurement,and a prediction accuracy of 99.51%is ***,we demonstrate that the ergodic spectra sensing accuracy is∼11.5%higher than that of simply extracting resonating modes’*** the high sensitivity and prediction accuracy,this work opens up a new avenue for integrated intelligent optical sensing.

关键词： measurement spectra prediction

Defects Localization Using the Data Fusion of Laser Doppler and Image Correlation Vibration measurements

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SSRN 2022年

作者： Sheng, Zhipeng Zhang, Kun Ge, Zhendong Yuan, Yingtao Chen, Bing Yan, keyu Fu, Yu Yu, Qifeng Shenzhen Key Laboratory of Intelligent Optical Measurement and Detection College of Physics and Optoelectronic Engineering Shenzhen University 3688 Nanhai Avenue Shenzhen518060 China Graduate School of Environmental Science and Technology Mie University Tsu514-0001 Japan School of Aeronautics Northwestern Polytechnical University Xi'An710072 China

This work proposes a defects localization method based on the combination of laser Doppler vibrometry (LDV) and Digital image correlation (DIC). DIC and LDV are the dominant non-contact vibration measurement methods with a matured theory and high stability. DIC gives a high spatial resolution with a measurement accuracy of several microns, whereas the Multipoint LDV has a limited spatial resolution with high-precision results for the sparse points up to nanometer level. However, the vibration-based defects localization necessitates certain measurement methods with both the high spatial resolution and measurement accuracy. Unfortunately, the resolution of DIC is not sufficient to detect the data anomalies caused by the structural defects. Nevertheless, LDV cannot achieve a high-precision defect localization owing to the limited spatial resolution. In this study, a nonlinear weighted least-squares fitting has been proposed to improve the measurement accuracy and reliability. A Chebyshev polynomial has been employed as the basis function in the fitting process. The effective signal-to-noise ratio (SNR) and the correlation coefficient are employed as the weight basis of the LDV points and the DIC subsets, respectively. Based on the simulation analysis, the determination of the optimal polynomial order at multiple noise levels and the influence of the LDV points distribution are discussed. The experiment proves that the data fusion method can significantly improve the spatial resolution and measurement accuracy. From the data fusion results, the reference-free defects localization in a cantilever beam and rectangular plate based on residuals have been presented. © 2022, The Authors. All rights reserved.

关键词： Vibration measurement

Efficient and Scalable Solar Energy Harvesting for Thermoelectric Generation: A 3-D Construction of Robust and Anti-Fouling Graphene

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SSRN 2024年

作者： Zhong, Hong Zhao, Qinghua Wu, Jiahao Ji, Yaxiong Lai, Zhongyu Yu, Qifeng Wang, Shifeng Qin, Qi Shenzhen Key Laboratory of Intelligent Optical Measurement and Detection College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen518000 China Innovation Laboratory of Materials for Energy and Environment Technologies College of Science Tibet University Lhasa850000 China Shenzhen International Graduate School Tsinghua University Shenzhen518000 China Department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic University 999077 Hong Kong

As a sustainable manner of energy exploitation, direct solar harvesting for thermal-electric generation based on photothermal conversion is promising but still challenging with the development of highly efficient, scalable, and structure durable photothermal materials. Firstly, we introduce a soft and facile technology for porous graphene fabrication via laser induced forward transfer (LIFT) process. This photothermal material with unique structure has large surface areas for solar absorption. Furtherly, the resultant photothermal graphene promoted thermoelectric generator has been obtained and shows an outstanding combination of strong solar irradiation absorption (more than 97%), excellent photothermal conversion ability, and extraordinary anti-fouling performance (a large water contact angle of more than 150 ° and small water sliding angle of lower than 5 °). A high output voltage of 144 mV could also be obtained under one sun illumination (Model number of thermoelectric generators is TEC1-12710). And the highest output power of 222.1 μW cm-2 could also be calculated under one sun illumination. A robust and durable photothermal-electric generator in real-environmental is demonstrated, which shows a great potential of the photothermal materials applied in highly solar energy harvesting. © 2024, The Authors. All rights reserved.

关键词： Graphene

On-chip Reconfigurable optical Neural Networks

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Research Square

Research Square 2021年

作者： Zhao, Xianmeng Lv, Haibin Chen, Cheng Tang, Shenjie Liu, Xiaoping Qi, Qin School of Physical Science and Technology ShanghaiTech University Shanghai201210 China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai201800 China University of Chinese Academy of Sciences Beijing100049 China College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen100049 China Shenzhen Key Laboratory of Intelligent Optical Measurement and Detection Shenzhen100049 China

Implementing artificial neural networks on integrated platforms has generated significant interest in recent years. Several architectures for on-chip optical networks with basic functionalities have been successfully demonstrated, for example, optical spiking neurosynaptic, photonic convolution accelerator, and nanophotonic/electronic hybrid deep neuron networks. In this work, we propose a layered coherent silicon-on-insulator diffractive optical neural network, of which the inter-layer phase delay can be actively tuned. By forming a close-loop with control electronics, we further demonstrate that our fabricated on-chip neural network can be trained in-situ and consequently reconfigured to perform various tasks, including full adder operation and vowel recognition, while achieving almost the same accuracy as networks trained on conventional computers. Our results show that the proposed optical neural network could potentially pave the way for future optical artificial intelligence hardware. © 2021, CC BY.

关键词： Silicon on insulator technology

Mapping optical Lateral Forces on the Poincaré Sphere

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ACS Photonics 2024年第8期11卷 3267-3275页

作者： Zhu, Yuchen Xiong, Sha Lai, Chengxing Wei, Zeyong Lu, Chengfeng He, Yujiang Song, Qinghua Wu, Pin Chieh Luo, Hong Wang, Zhanshan Xie, Lingyun Shi, Yuzhi Cheng, Xinbin Institute of Precision Optical Engineering School of Physics Science and Engineering Tongji University Shanghai200092 China MOE Key Laboratory of Advanced Micro-Structured Materials Shanghai200092 China Shanghai Institute of Intelligent Science and Technology Tongji University Shanghai200092 China Shanghai Frontiers Science Center of Digital Optics Shanghai200092 China School of Automation Central South University Changsha410083 China Technology Innovation Center of Mass Spectrometry for State Market Regulation Center for Advanced Measurement Science National Institute of Metrology Beijing100029 China Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen518055 China Department of Photonics National Cheng Kung University Tainan70101 Taiwan

optical lateral forces (OLFs) play progressively important roles in optical manipulation, finding numerous applications in enantioselective sorting and sensing. Probing OLFs on achiral particles is also essential in interpreting extraordinary light-matter interactions. Recent advances have shown that the OLF can emerge from the transverse Belinfante spin momentum (BSM) and get maximum values when the light is circularly polarized. Here, by searching the Poincaré sphere, we find that the optical gradient force and radiation pressure correlate strongly with the ellipticity and azimuthal angles on the Poincaré sphere, which may exceed the OLF in a focused line-shaped beam. Consequently, the total lateral force may reach its maximum under the elliptical polarization rather than the circular polarization. Meanwhile, the ellipticity angle corresponding to the maximum force varies significantly with the particle size and its refractive index. Our work unravels a novel and efficient way to harness optical forces in a full-polarization manner and provides a new playground for various biophysical applications. © 2024 American Chemical Society.

关键词： Refractive index