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HUANG Bohang, JIANG Tinghao, ZHAO Chunbo, WU Tengfei, HE Guangqiang
2025(6):10-28 ,DOI: 10.11823/j.issn.1674-5795.2025.06.01
Abstract:
The basic principles of precision ranging based on soliton microcombs and their advantages in chip-level integration, high precision, and high speed are introduced. The principles and implementations of single-microcomb frequency-modulated continuous wave, chaotic ranging, dispersive interferometry, synthetic-wavelength metrology, and dual-comb ranging are elaborated. The development paths such as repetition frequency locking, frequency scanning, and parallel imaging are discussed. It is pointed out that the research in this field has progressed from proof-of-concept demonstrations to a new stage focused on performance optimization and practical exploration. It is further proposed that the future development will be characterized by system-level full optoelectronic integration, multifunctional reconfigurability, and deep cross-disciplinary convergence, through which a large-scale deployment of chip-scale precision LiDAR in automotive perception, industrial metrology, space exploration, and related applications is expected to be enabled.
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HAN Yixuan, GAO Doudou, DONG Dengfeng, WANG Bo, QIU Qifan
2025(6):29-40 ,DOI: 10.11823/j.issn.1674-5795.2025.06.02
Abstract:
To address the issues of accuracy degradation and computational delay in extracting small spot centers in the field of industrial high-speed visual measurement, a high-speed real-time spot localization method for small-sized spots is proposed. A Region of Interest (ROI) extraction algorithm based on sliding window brightness consistency is designed and implemented in a Field Programmable Gate Array (FPGA) to improve detection speed. A small spot center extraction algorithm combining distance-weighted least-square fitting and a Signal-to-Noise Ratio (SNR)-based adaptive weight adjustment mechanism is introduced to enhance the localization robustness of small spots under varying lighting and noise conditions. Experimental results show that the proposed method has achieved a spot center localization error of not more than 0.05 pixels, with a frame rate of 160 frames per second, significantly outperforming traditional methods in processing speed. This method to a great extent meets the high-precision real-time localization requirements of small spot centers in industrial high-speed visual measurement.
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CHENG Xin, CONG Shanshan, XUE Zhipeng, LIU Jinquan, MIAO Zijian, WANG Sheng
2025(6):41-49 ,DOI: 10.11823/j.issn.1674-5795.2025.06.03
Abstract:
To address the bottlenecks of high cost and long development cycles in traditional aerospace product manufacturing, and to meet the urgent demand for batch production of space optical payloads in giant satellite constellations, this study adopts an integrated approach combining modular structural design, process optimization, and automated testing technology to develop a Maksutov-Cassegrain optical system with a small F-number and minute pixels. By enab-ling interchangeable assembly of lenses and focal plane components, along with integration into an automated assembly and testing line, the system achieves a ground pixel resolution of 4.5 m and a swath width of 13.5 km × 13.5 km at an orbital altitude of 500 km, with a total weight of only 1.1 kg. This approach has improved the overall development efficiency by 50%. The results provide crucial technical support for the low-cost, rapid, and batch-producible manufacturing of miniaturized space optical payloads.
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DU Qiang, HAO Jianhai, BAI Jinhai, HU Dong, WANG Yu, XU Haotian, ZHANG Yeyuan
2025(6):50-64 ,DOI: 10.11823/j.issn.1674-5795.2025.06.04
Abstract:
This paper introduces the physical principles and typical methods of Rydberg atomic superheterodyne microwave measurement technology, elaborates on its research advancements in sensitivity enhancement, phase measurement, and dynamic range expansion, analyzes its potential value and current limitations in aviation equipment applications, and explores the developmental trajectory and key technical challenges involved in transitioning this technology from laboratory research to practical aviation applications. It points out that the current maturity level of this technology is in the transitional stage from theoretical breakthroughs to equipment integration. Furthermore, it proposes a three-phase roadmap for advancing this technology toward aviation applications: chip-scale integration of core units, enhanced environmental robustness at the system level, and mission-oriented networked collaborative sensing. It provides a prospective technology roadmap for constructing a new generation of highly sensitive, distributed, and intelligent aviation microwave measurement systems.
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PAN Yan, WANG Nuanrang, WANG Yunjia, FENG Shilong, XUE Xiaobo, ZHANG Shengkang
2025(6):65-72 ,DOI: 10.11823/j.issn.1674-5795.2025.06.05
Abstract:
To accurately and efficiently control the probing sequence of the Hg? microwave atomic clock, a highly integrated custom timing control system was developed. This system adopts a layered architecture design, in which the host computer software enables parameter setting and sequence configuration distribution. The embedded software, in real-time, parses the received instructions and generates high-precision operation sequences, ultimately driving peripheral devices to precisely execute the corresponding operations. It achieves flexible configuration and dynamic reconfiguration of the timing logic. Experimental results show that the sequences generated by the system are consistent with the theoretically designed sequences, enabling convenient and efficient timing control for double-resonance probing, Rabi probing, and Ramsey probing. The system provides a reliable timing control solution for the integrated research of Hg? microwave atomic clocks.
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ZHANG Yu, YANG Hongwei, LIU Fang, YANG Wengang, JIANG Hongchuan, DENG Xinwu
2025(6):73-85 ,DOI: 10.11823/j.issn.1674-5795.2025.06.06
Abstract:
O? and H?O significantly affect the hydrogen sensitivity of PdNi thin films. To monitor hydrogen concentration in high-humidity oxygen-containing environments such as electrolytic water hydrogen production, nuclear power plant storage, and deep-sea energy exploration, PdNi thin-film hydrogen sensors were fabricated using methods such as magnetron sputtering, photolithography, and plasma etching. By adjusting the Ni content and thickness of the PdNi thin films, the influence of Ni content and thickness on the stability of the PdNi thin-film hydrogen sensors under O? and H?O interference was systematically studied. Analytical methods such as XRD, SEM, and XPS were employed to characterize the crystallinity, elemental content, and elemental valence states of the PdNi thin films. The experimental results indicate that as the Ni content increases, the hydrogen response of the PdNi thin films becomes more affected by H?O and O?, while increasing the film thickness can reduce interference but weakens the hydrogen response sensitivity. Among them, the PdNi thin-film hydrogen sensor with a Ni content of 8.04% and a thickness of 24 nm, although affected by O? and H?O, can restore its response curve to the initial state after experiencing interference. This research provides important support for the development of the hydrogen sensor for applications under complex environment conditions.
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JIN Ran, HUANG Yuqi, ZHU Liang
2025(6):86-94 ,DOI: 10.11823/j.issn.1674-5795.2025.06.07
Abstract:
To address the calibration demand for the response time constant of fast-response K-type thermocouples under gas medium conditions, a calibration device based on the gas temperature step method was developed. Key para-meters including heater power, orifice area, and nozzle flow rate were determined via theoretical calculations, and Ansys Fluent software was utilized for simulation to optimize the structure of the step temperature generation module. A calibration method based on synchronous dynamic pressure monitoring was proposed, which takes the pressure step moment as the reference to eliminate non-ideal excitation interference and ensure the calculation accuracy of the response time constant. Experimental tests were conducted using the developed device, and the results indicate that the gas temperature step amplitude generated by the device exceeds 200 ℃ with a temperature step excitation time of approximately 2.2 ms. The device can effectively calibrate the response time constant of K-type thermocouples with different wire diameters, demonstrating a significant engineering application value.
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LIAO Yunhong, WANG Chenchen, FU Qiang
2025(6):95-104 ,DOI: 10.11823/j.issn.1674-5795.2025.06.08
Abstract:
Research was conducted for porous parameter inversion based on irregular acoustic incidence model to address the limitation of normal incidence case. A theoretical model was established for relating material porous parame- ters to the irregular incidence absorption coefficient. The acoustic response of porous materials under irregular incidence case was simulated to obtain the reference absorption data. The inversion study was conducted by using the established theoretical model and genetic algorithm, and the accuracy and astringency of inversed parameters was further analyzed. Results show a good agreement between theoretical and simulated outcomes and demonstrate high accuracy and astringency with relative errors of the inversed parameters below 9.0% and relative standard deviations less than 1 × 10?3. This study provides a novel theoretical approach for porous parameter inversion that presents considerable potential for both academic research and engineering applications.
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WANG Siyu, CUI Yuguo, WEI Chunfeng, CHEN Jichi
2025(6):105-115 ,DOI: 10.11823/j.issn.1674-5795.2025.06.09
Abstract:
To improve the quality and efficiency of Digital Elevation Model (DEM) construction in complex terrain, this study proposes a multi-source DEM acquisition and fusion method that integrates high-resolution optical imagery and interferometric Synthetic Aperture Radar (SAR) imagery. Using an unmanned aerial vehicle and satellite remote sensing system as a platform, this method constructs a multi-view data acquisition chain to generate optical imagery DEM and interferometric imagery SAR-DEM, respectively. By introducing a point cloud classification algorithm based on texture and structural features and a regional adaptive weight estimation model, weighted fusion of multi-source elevation data has been achieved. The fusion process employs error constraints and seamline control strategies to address typical challenges such as terrain occlusion, data holes, and elevation jumps. Experiments in representative landforms, including forests, glaciers, deserts, cities, and water bodies, demonstrates that this method has the characteristics of high elevation restoration accuracy and good boundary continuity, and can meet the three dimensions modeling needs of various landform types. Among them, the relative elevation mean error in hilly areas is 0.5 m. The research findings provide stable and reliable technical support for fields such as high-resolution topographic mapping, landform evolution monitoring, and disaster early warning, and are of great significance for promoting the automation and intelligence of remote sensing mapping.
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MENG Wei, SHI Wei, CHEN Shilin
2025(6):116-127 ,DOI: 10.11823/j.issn.1674-5795.2025.06.10
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To systematically solve the application problems of Measurement System Analysis (MSA) in the automatic hardness detection system, the particularity of its MSA is expounded, and points out the limitations of the traditional Gauge Repeatability and Reproducibility (GRR) method in the identification of variation sources and experimental design. On this basis, a "process decoupling hybrid GRR" experimental strategy is proposed, which decouples the hardness testing process into two sub processes: indentation generation (destructive) and indentation measurement (non-destructive). Nested design and cross design are used to separate and quantify the variation sources, respectively. Through the construction of an automation platform with double detection units, the systematic MSA experiment was conducted, and the analysis of variance was used to evaluate the influence of equipment repeatability, reproducibility and interaction. The results show that the proposed method can effectively identify the dominant variation sources, and provide a feasible analysis framework for the performance evaluation and optimization of the automatic hardness testing system, which has strong engineering applicability and popularization value.
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SHI Chunying, ZHANG Yixiang, HU Wanxin, XING Runjia
2025(6):128-140 ,DOI: 10.11823/j.issn.1674-5795.2025.06.11
Abstract:
To accurately evaluate the metrological performance of airborne sensors under the prolonged, gradual, and cumulative influence of the natural environment, this study examines key technical aspects of the testing process — including preliminary preparations, test design, execution, result analysis, and reporting — based on the characteristics of both airborne sensors and natural environments. This exploration has resulted in the development of a relatively universal methodology for conducting natural environmental tests. These tests generate fundamental data on the changes in sensor metrological indicators, providing essential support for subsequent research on the performance degradation and the calibration cycle of airborne sensors.
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ZHENG Jianhua, ZHAO Jian, WANG Xiaolu, HU Lintao, KONG Xiangxue, ZHAO Yijun
2025(6):141-152 ,DOI: 10.11823/j.issn.1674-5795.2025.06.12
Abstract:
Accurate heat flux measurement is essential for developing hypersonic vehicles and their thermal protection systems. The intense aerodynamic heating generated during high-speed flight of aerospace vehicles is primarily dominated by convective heat transfer. However, existing heat flux gauges struggle to accurately measure surface thermal loads under extreme high-temperature and high-speed conditions, resulting in low measurement accuracy and significantly constraining the performance evaluation of thermal protection systems and material development. To address the lack of reliable calibration methods for heat flux sensors under high-temperature and high-speed conditions, this study introduces a dual-plate transient calibration method. This method adopts a highly accurate thin-film platinum resistance sensor as a reference, installs a Gardon gauge to be calibrated with the sensor together on a displacement ejection mechanism, and simulates the high-speed flight scenario of the aircraft in the wind tunnel to achieve the calibration to the Gardon heat flux gauge under airflow conditions. Calibration experiments were conducted at a flight Mach number of 0.3 and temperatures from 100 °C to 300 °C for the developed convective heat flux measurement device. The results demonstrate that the relative expanded uncertainty is 4.2% (k = 2), and this method can effectively obtain the convective heat flux sensitivity coefficient of the Gardon heat flux meter. The dual plate transient calibration method proposed in this paper provides new ideas and approaches for high-temperature and high-speed convective heat flux calibration, significantly improving the reliability of convective heat flux measurement data and providing strong technical support for the development of hypersonic aircraft and accurate measurement of thermal loads in thermal protection systems.
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WANG Yida, TIAN Qingyun, CHEN Yong, KONG Xiangxue, MANG Kexin, WANG Sujie, SHI Jiyuan
2025(6):153-160 ,DOI: 10.11823/j.issn.1674-5795.2025.06.13
Abstract:
Traditional test equipment struggles to meet the high-precision and efficient static temperature testing requirements of thin-film thermocouples in high-temperature environments. To address this issue, a chamber furnace with large-space and precise temperature control functions has been developed. The furnace body adopts a split-type multi-layer structure design. Its side thermal insulation components can be flexibly disassembled to eliminate installation obstructions, satisfying the testing needs of thin-film thermocouples with different shapes. High-efficiency heating is achieved using three-section molybdenum disilicide heating elements, combined with a water-cooling system to realize precise temperature control and generate a stable and reliable temperature field. A three-dimensional thermodynamic model was established and simulated using ANSYS Workbench 2019R3 software. The simulation results show that the temperature field at the measuring end and the temperature at the reference end of the sample meet the design expectations. Practical tests conducted with the developed box-type furnace indicate that the temperature fluctuation in the furnace's test coordinate system is 0.47 ℃ / 6 min, and the temperature field uniformity is better than 3 ℃ / 50 mm, which complies with the testing requirements for thin-film thermocouples. Tests on Au-Pt thin-film thermocouples were conducted using this box-type furnace, further verifying its application effectiveness. It provides important technical support for the static temperature characteristic detection of thin-film thermocouples.
Volume ,2025 Issue 6
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Research Progress and Prospects of Ultrasonic Velocimetry Reconstruction Algorithms for Complex Flow Fields
Abstract:
Ultrasonic velocity measurement technology has become a research focus due to its non-invasive and pressure-loss-free advantages in addressing the measurement challenges of complex distorted flow fields, such as those in aero-engine intakes and industrial pipelines. This review introduces mainstream ultrasonic velocimetry methods, detailing the fundamental principles and calculation formulas of the transit-time method and the Doppler method. It focuses particularly on the ill-posed inverse problem inherent in ultrasonic velocity field reconstruction, providing an in-depth analysis of the mechanisms, strengths, and inherent ill-posedness of classical inversion algorithms including the least squares method, Tikhonov regularization, and truncated singular value decomposition (TSVD). The article summarizes key physical-signal joint processing strategies for mitigating significant ultrasonic beam drift and low signal-to-noise ratio (SNR). Looking ahead, it highlights the integration of physics-informed algorithms, multi-physical field coupling, and system-on-chip implementation as pivotal pathways for advancing the technology toward enhanced precision, adaptability, and miniaturization. This work serves as a reference for future breakthroughs and the engineering application of ultrasonic velocimetry technology.
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Research on Peak Detection and Correction Method for Periodic Fatigue Test Data of Aviation Structural Components
Abstract:
The fatigue test of aviation structural components is one of the key links to verify the fatigue strength and durability of the structure. How to accurately detect and correct the peak value of test data with periodic and large data characteristics is directly related to the effectiveness of aviation structural life prediction and damage assessment. This article uses fiber Bragg grating strain sensors to monitor the health of a certain type of aviation structural component. Based on the data obtained during fatigue testing, the problem of data errors caused by spectral distortion is first solved. Subsequently, a method for detecting and correcting peak values of periodic fatigue test data is proposed, which achieves rapid detection and correction of peak and valley values of test data. This method is superior to traditional methods in terms of efficiency, accuracy, and robustness, and is suitable for key scenarios such as aircraft structural health monitoring and fatigue life assessment.
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FMCW Laser Ranging Method Based on Electro-Optic Double-Sideband Modulation
CUI Hang, ZHANG Hengkang, WANG Shuzhen, SUN Haifeng, MENG Xiawei, ZHANG Shuwei, LI Xiaoping
Abstract:
Traditional frequency modulated continuous wave (FMCW) laser ranging techniques are mostly implemented using tunable lasers or dual-light-source architectures. These systems are complex and difficult to engineer, and they suffer from error amplification in dynamic scenarios. To address these limitations, our research team proposes an FMCW laser ranging method based on electro-optic double-sideband (DSB) modulation. A frequency-stabilized laser and an electro-optic modulator are used to generate two oppositely swept frequency signals, which reduces the system size and mitigates dynamic errors. An all-phase fast Fourier transform (AP-FFT) algorithm is designed to achieve stable and reliable phase retrieval under highly dynamic and high-noise conditions. In addition, Kalman filtering is introduced to optimize dynamic state estimation and improve ranging stability. Experimental results show that, with a 20 m fiber link, the absolute distance measurement error of the proposed method does not exceed ±20 μm. For a sinusoidally vibrating target with amplitude ≤ 500 nm and frequency ≤ 200 Hz, the relative displacement measurement error does not exceed ±25 nm. These results verify the high reliability of the proposed method and provide strong support for promoting the engineering deployment of FMCW laser ranging technology.
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Online Measurement and Compensation of Six-Degree-of-Freedom Errors for Z-Axis of micro-nano CMMs
Abstract:
As a key component in micro/nano machining and measurement equipment, the Z-axis is subject to manufacturing and assembly errors, which introduce six-degree-of-freedom (6-DOF) geometric errors that directly degrade metrology and machining precision. A measurement method is proposed for the Z-axis linear and angular errors based on laser interferometry and autocollimation. An error compensation model is established by analyzing the spatial position errors of functional points on the CMM, founded on Abbe and Bryan principles. The proposed method was implemented on a micro/nano-CMM, where an online 6-DOF error measurement system were developed. Measurements were performed along the Z-axis on a grade 0 gauge block with a thickness of 8 mm using the CMM. The results show that the measurement standard deviation and indication error were reduced by 54.6% and 54.3%, respectively, after compensation. This method and system provide a reliable solution for improving the measurement and machining accuracy of CMMs and other precision equipment.
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Fatigue Testing and Life Prediction Modeling of Silicon-Based Piezoresistive Pressure Sensors
Abstract:
Silicon-based piezoresistive pressure sensors suffer from insufficient reliability and reduced service life due to issues such as output drift and sensitivity degradation in harsh environments. This study aims to systematically elucidate the physical mechanisms behind their stability degradation and to develop a high-precision life prediction model. Utilizing the physics of failure analysis theory, the research employed variable-amplitude cyclic loading and accelerated fatigue testing. Accelerated tests were conducted by applying alternating pressure with different amplitudes. A dataset of sensor failure degradation was established through microscopic examination and performance monitoring. This approach overcame the challenge of analyzing the coupled effects of multiple mechanisms, including diaphragm cracking, piezoresistor creep, and packaging stress failure, ultimately enabling the construction of a life prediction model under uniaxial pressure loading conditions. Accelerated life testing demonstrated that under a pressure load of 140% of the full-scale range, the sensor's linearity increased by over 50% after approximately 2.2 million cycles, which was defined as failure. The developed model achieved an error of less than 15% between the predicted and measured lifespan, enabling effective prediction of the sensor's failure cycle. The fatigue experiments conducted and the life prediction model developed in this study effectively meet the engineering requirements for reliability assessment and life extension of pressure sensors. This work holds significant theoretical and practical application value, providing crucial support for advancing the design optimization and lifetime prediction of highly reliable silicon-based pressure sensors.
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Research Status and Prospects of LiDAR Point Cloud and Visible-Light Image Fusion Technology
Abstract:
Lidar point cloud and visible image fusion technology, by integrating three-dimensional point clouds with two-dimensional texture and color information, can provide a richer and more accurate data foundation for environmental perception. Compared to conventional LiDAR, single-photon LiDAR offers advantages such as photon-level sensitivity and picosecond-level timing precision, enabling high-precision three-dimensional point cloud imaging over long distances and in low-observability scenarios. The fusion technology of single-photon LiDAR with visible images provides a new pathway for addressing target recognition and localization challenges in complex environments. This paper introduces the fundamental principles of conventional/single-photon LiDAR systems and image fusion technology, analyzes the feature differences between conventional/single-photon LiDAR and visible images as well as the issue of image registration, elaborates on the research and application status of fusion technology between conventional/single-photon LiDAR and visible images, and finally summarizes and prospects the current state of conventional/single-photon LiDAR and visible image fusion technology.
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Influence Mechanism of Beam Incident Angle on Angular Measurement Accuracy and Compensation in Rotational Scanning Systems
Abstract:
Rotational laser scanning angular measurement systems have been widely applied in large-scale structural assembly and spatial pose monitoring due to their distributed architecture, high accuracy, and efficiency. However, variations in receiver orientation lead to changes in the beam incidence angle, introducing systematic angular measurement errors that affect the system’s precision and robustness. To address this issue, a local projection model and a Gaussian light-strip distribution model were established based on beam propagation geometry and receiver structural characteristics, and differences in photoelectric response under different incidence conditions were analyzed. Furthermore, by incorporating attitude information provided by an inertial measurement unit (IMU), an effective receiving surface model was constructed in the receiver coordinate system, and an error compensation method considering receiver structural features was proposed. Simulation results show that as the incidence angle increases, the photoelectric response waveform of the receiver becomes significantly asymmetric, with angular measurement errors reaching several tens of arcseconds. The proposed compensation method effectively corrected these errors, reducing the root-mean-square (RMS) error by approximately 90%. In precision turntable experiments, the roundness error of the receiver trajectory decreased from 0.81 mm before compensation to 0.17 mm after compensation, confirming the effectiveness of the compensation model. The study enriches the error modeling framework of rotational laser scanning systems and provides an effective approach to enhance measurement accuracy and robustness under varying receiver attitudes.
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Research on the Localization Accuracy of Spot for Four-Quadrant Superconducting Nanowire Single-Photon Detector
Abstract:
This study addresses photon count distortion in four-quadrant superconducting nanowire single-photon detectors (QD-SNSPD) under high count rates and positioning difficulties under low signal-to-noise ratio (SNR) conditions. The nonlinear correction mechanism for photon counts is studied and an analytical solution for Gaussian spot localization problem is derived. A differential localization method using non-integer power operations is proposed, which increase signal differentiation between positive and negative semi-axes through an exponent n>1 to improve positioning accuracy. Results demonstrate that count correction improves spot localization accuracy under high count rates. Non-integer power operations effectively reduce positioning errors under low SNR conditions. Compared with classical differential localization methods, the 1.4-power operation reduces positioning errors by 27% when SNR < 10. The corrected Gaussian model reduces errors by 70% when SNR > 50. When photon counts exceed 10^4, both the corrected Gaussian model and power operation methods (0.8≤n≤2) achieve a positioning standard deviation below 0.01 times the spot radius. These findings provide substantial support for high-precision spot localization using QD-SNSPDs.
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In-situ calibration method for ultra-micro-spot angle-resolved polarization scatterometer
Wang, Wei, Liu, Jiamin, Cui, Xue, Liu, Shiyuan
Abstract:
Angle-resolved scattering, as a typical optical scattering measurement technique, has been widely employed in integrated circuit (IC) manufacturing for high-precision in-line measurement of nanofilm thickness, nanostructure topography parameters, and overlay errors. Its non-destructive nature, high sensitivity, high efficiency, and compact design make it well-suited for these applications. In this study, we developed an angle-resolved polarization scatterometer that integrates ultra-micro-spot polarized illumination with amplitude-division polarization analysis. This system enables single-shot simultaneous acquisition of both real-space and orthogonally polarized frequency-domain images of complex nanostructures within microscopic regions. Since the polarization properties of optical components such as the polarizer, waveplate, and polarization beam splitter significantly constrain measurement accuracy, this study proposes an in-situ stepwise calibration method for system parameters. Based on the principle of extinction ellipsometry, the polarizer azimuth, waveplate retardation and azimuth, polarization beam splitter reflection and transmission ellipsometric parameters, and objective lens orthogonal polarization transmittance were sequentially calibrated with high precision to ensure instrument accuracy. The effectiveness of the proposed calibration method was verified through measurement experiments on standard SiO? thin films and rectangular grating samples. The results indicate that the in-situ calibrated instrument achieved a film thickness measurement repeatability of 0.1 nm, and the grating morphology parameters were in excellent agreement with standard values. This work provides a reliable and accurate in-line measurement method for nano-thin films and nanostructures, supporting process monitoring in advanced IC manufacturing.
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Research on Calibration Methods for Structured Light 3D Measurement Systems on Multiple Types of Non-Diffuse Reflective Surfaces
ZHAO Huijie, YANG Xu, LI Xiang, JIANG Hongzhi
Abstract:
As a crucial measurement tool for acquiring the 3D topography of measured surfaces in the industrial field, the measurement accuracy of structured light 3D measurement systems is jointly determined by standard standards, calibration principles, and calibration methods. However, for complex optical characteristic surfaces that are increasingly common in the field of high-end industrial manufacturing, such as translucent surfaces, high-reflective surfaces, and high-dynamic range reflectivity surfaces, current domestic and international metrological standards (e.g., VDI/VDE 2634 - Optical 3D Measuring Systems, and JJF 1951-2021 Calibration Specification for Optical 3D Measurement Systems Based on Structured Light Scanning) only specify requirements for diffuse reflection standards and diffuse reflection surfaces, which can no longer meet the actual calibration needs. Therefore, targeting the complex industrial application scenarios of structured light 3D measurement systems, this study defines translucent surfaces, highly reflective surfaces, and surfaces with high dynamic range reflectivity from the perspective of optical properties, designs standard standards suitable for different surfaces, further improves calibration principles according to calibration requirements, and proposes corresponding calibration methods. This enables the calibration of key geometric parameters (e.g., curved surfaces, flat surfaces, and distances) measured by structured light 3D measurement systems for multiple types of measured surfaces. It serves as a supplement and improvement to the existing calibration standards for structured light 3D measurement systems, and plays an important role in promoting the development of the industrial manufacturing field toward precision, automation, and standardization.
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Two-dimensional wind retrieval for wind lidar based on relative total variation model
Abstract:
Wind lidar can only directly measure the radial components of wind vectors. So two-dimensional（2D）wind retrieval is crucial for reconstructing wind structure. To address the issue of wind-speed distortion in the 2D wind retrieval using traditional Velocity Azimuth Processing（VAP）algorithm, the relative total variation（RTV）model is incorporated to improve the algorithm. Based on the correlation between wind-speed distortion and radial wind speed, a threshold is established to identify distorted regions ,enabling subsequent correction. Then the RTV model is employed to eliminate irregular textures generated during the correction process and extract the 2D overall wind structure . And local texture features are reconstructed by the texture information from the actual radial wind speed. Experimental results demonstrate that the improved algorithm effectively mitigates the wind-speed distortion issue in VAP algorithm. Compared to the preliminary results retrieved by VAP algorithm, the improved algorithm reduces root mean square error by 0.42 m/s for wind speed and 4.85 for wind direction, significantly improving the accuracy of wind retrieval.
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Research on Automatic Positioning and Scanning Technology of Laser Tracker for Curved Surface Measurement
LI Yan, 孙安斌, FAN Shuaixin, 孟宇航
Abstract:
In response to the requirements for automatic positioning and scanning of component curved surfaces during aircraft assembly, relevant research was conducted using the Leica ATS600 laser tracker. Based on the SpatialAnalyzer (SA) software, secondary development was carried out using Measure Plan and SA SDK, and a research method for automatic positioning and scanning technology of laser trackers was proposed. The research process is as follows: first, connect the measurement equipment and import the curved surface digital model and theoretical positioning point information; then, measure the positioning features and curved surfaces; subsequently, perform digital model alignment and relationship matching between the actual measured information of the curved surface and the theoretical information, and automatically generate a report based on the matching results. Finally, a set of automatic positioning and scanning system for curved surface measurement was built, and a large-scale curved surface standard device was used as the experimental object for measurement. The results show that the program runs stably, effectively addresses the inherent shortcomings of SA, and significantly improves the efficiency and automation level of curved surface scanning.
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Full-field spectral-domain interferometry and its application based on digital micromirror device
Abstract:
Current full-field spectral-domain interferometry relies on wavelength or galvanometer scanning, which limits their ability to acquire full-field information in a single detection. To address this issue, this paper proposes a full-field spectral-domain interferometry technique based on a digital micromirror device (DMD). By encoding the spatial light field distribution via the DMD, time-varying spectral signals corresponding to sequentially loaded masks are acquired, which are further decoded to obtain the amplitude response at each spatial pixel. Combined with the measurement algorithm, full-field information retrieval is achieved. Experimental results demonstrate that the proposed technique enables high-precision spectral interferometric distance measurement and spectroscopic ellipsometric film thickness measurement, while significantly improving full-field measurement efficiency. The DMD-based full-field spectral interferometry technique is suitable for rapid three-dimensional structure recovery and reconstruction of sparse surfaces, providing strong support for efficient thickness and topography characterization of polished wafers, silicon-on-insulator (SOI) substrates, and bonded interfaces.
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Laser Ranging Based on Optical Frequency Combs: Status and Perspectives (Invited)
Abstract:
Laser ranging systems are advanced ranging systems that integrate laser and optoelectronic detection technologies. With advantages such as high resolution, strong anti-interference capability and compact size, they have attracted extensive attention in recent years. At present, laser ranging has been widely applied in fields including autonomous driving, artificial intelligence and military defense. Driven by complex application demands, high detection resolution, fast update rate and long detection range have become the core goals for the continuous iteration and upgrading of laser ranging technology. Optical frequency comb, whose spectrum consists of a series of evenly spaced discrete frequency components with stable phase relationships and which simultaneously provides time-domain pulses with stable spacing, serves as a natural “time–frequency” reference and “photon–radio-frequency” bridge. It has been widely used in precision metrology, high-speed communications, microwave generation and fiber-optic sensing. In recent years, the rapid development of optical frequency comb technology has significantly improved the performance of laser ranging systems, creating new advantages in terms of measurement accuracy, speed and range, and becoming an important breakthrough for extending the functionality and enhancing the performance of next-generation laser ranging systems. This review focuses on laser ranging technologies based on optical frequency combs, provides an overview of the principles, characteristics and development status of optical frequency combs, summarizes typical methods and recent research progress in comb-based ranging, and finally presents a summary and outlook on the current research status and future development of this field.
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Optimization Algorithm for the Deployment of Heterogeneous Nodes in Energy-Isoform Sensor Networks
Abstract:
The wireless sensor network is a crucial component of the Internet of Things (IoT), and ensuring its efficient operation has become one of the prominent research challenges today. By incorporating energy-replenishable heterogeneous nodes into the network, it is possible to effectively extend the network's lifespan. This paper establishes criteria for selecting the locations of heterogeneous nodes based on characteristics such as network coverage and data transmission distance. We propose an optimization deployment algorithm specifically designed for positioning heterogeneous nodes within heterogeneous wireless sensor networks, and we conduct a simulation analysis comparing our proposed algorithm with existing methods. The results indicate that our proposed algorithm demonstrates superior performance in terms of data transmission volume and energy consumption.
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Research progress on applications of scanning tunneling microscopy in atomic-scale measurement, characterization, and manufacturing
CHAI Yu, CHEN Dezhang, LI Dezhi, LYU Kaihang, LI Haopeng, DANG Chaoqun, JU Bingfeng
Abstract:
The scanning tunneling microscope (STM) is a pivotal instrument that integrates the capabilities of atomic-scale measurement, characterization, and fabrication. It simultaneously fulfills the three core requirements of atomic-scale manufacturing: "visualization," "precision measurement," and "fabrication feasibility." Atomic-scale manufacturing aims for precise manipulation at the spatial scale of meters, with associated electronic dynamics occurring on ultrafast timescales ranging from femtoseconds to attoseconds. With its high spatiotemporal resolution, STM serves as a key experimental technique for revealing physical mechanisms and quantum effects at the atomic scale, significantly advancing the field from fundamental exploration to practical application. Based on the unique quantum tunneling effect, STM performs precise measurements of physical properties (e.g., electronic and magnetic) in fabricated structures. This establishes quantitative structure-property relationships between fabrication parameters and device performance,thereby providing a critical basis for process optimization and quality assessment. Furthermore, STM possesses the inherent ability for precise atomic-scale manipulation. The deep integration of STM with high-throughput and automation technologies is emerging as a core pathway to transition STM-based atomic-scale manufacturing from laboratory proof-of-concept to industrial application. This review summarizes the current research progress in the application of STM for atomic-scale measurement, characterization, and manufacturing, outlines existing challenges, and provides perspectives on future development trends.
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