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Research on the cascade modulation method for star position simulation in a weak starlight simulator

Optics Express 2025年第3期33卷 5627-5639页

作者： Wu, Linghao Zhang, Yu Li, Yihuan Sheng, Lan Xia, Yuxin Zhang, Siqi Gu, Siwen Department of Measurement and Control Technology and Instrumentation Changzhou Institute of Technology Changzhou213032 China Changchun University of Science and Technology Changchun130022 China

In order to surmount the challenge wherein the gray-scale resolution of liquid crystal on silicon (LCOS) imaging within a faint starlight simulator acts as a limiting factor for the precision of stellar position correction, this paper introduces a design approach for a cascaded architecture tailored to faint starlight simulators. Through the implementation of an isometric mapping technique that maps the dimming LCOS onto the surface of the imaging LCOS, the dimensionality of gray-scale adjustment for the imaging LCOS is augmented, thereby enhancing the accuracy of simulated stellar position correction. Initially, a stellar position cascaded modulation architecture is meticulously constructed to investigate the pivotal factors that impact the gray-scale resolution of the imaging LCOS within the framework of the cascaded modulation architecture. Subsequently, the optimization protocol for the concentrator system embedded within the cascaded modulation architecture is formulated. Leveraging the simulated annealing algorithm, the multi-parameter freeform surface of the concentrator system undergoes synchronous optimization. Finally, the simulation outcomes derived from the cascaded modulation architecture both prior to and subsequent to optimization clearly demonstrate that upon the implementation of the novel architecture, the accuracy of simulated stellar position correction experiences a notable enhancement of 62%. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Liquid crystals

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Laser triangulation-based distance measurement using deep neural networks 11

Laser triangulation-based distance measurement using deep ne...

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Optical Metrology and Inspection for Industrial Applications XI 2024

作者： Zhang, Hao Zhong, Jiaxing Wang, Shiji Department of Measurement and Control Technology and Instrumentation Dalian Maritime University Dalian116026 China

ISBN: (纸本)9781510682108

This work aims to simplify and optimize the data processing of laser triangulation ranging method by utilizing deep learning for intelligent measurements, leading to enhanced measurement accuracy. Firstly, a nonlinear programming genetic algorithm with elitist strategy (E-NPGA) is employed to determine the optimal optical system parameters, resulting in the development of a laser triangulation ranging system. A deep neural network is then established for distance evaluation. Experimental results demonstrate that the deep learning based method proposed in this work enables a distance measurement with a root mean squared error within the range of 0.8 to 1 µm and a mean absolute error of below 0.7 µm, which offers a f easible i ntelligent m easurement approach. © 2024 SPIE.

关键词： Mean square error

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System parameter optimization with improved genetic algorithm for laser triangulation sensors 14

System parameter optimization with improved genetic algorith...

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14th International Conference on Information Optics and Photonics, CIOP 2023

作者： Zhang, Hao Wang, Shiji Wang, Jieping Department of Measurement and Control Technology and Instrumentation Dalian Maritime University Dalian116026 China

ISBN: (纸本)9781510671744

Laser triangulation ranging sensors, with their micron precision, simple principles and compact structures, are widely applied in the industry for instance for workpiece shape and defect measurements. However, the determination of system parameters for laser triangulation sensors currently depends on the experience and manual attempts of designers, which is not only time-consuming but also enables additional measurement errors. In this work, we present a genetic algorithm based method to accurately, fast, and adaptively determine the optimal system parameters for various measurement requirements. Based on the Scheimpflug principle, measurement range and resolution expressions are first derived for laser triangulation systems. The formulas of laser spot size in the x- and y-directions of image detectors are presented and the system geometric dimension is constrained when setting the measured surface on the calibration reference plane. Furthermore, a nonlinear programming genetic algorithm (NP-GA) is proposed to evaluate system parameters for certain measurement conditions, in which the local search capability is significantly improved with rapid convergence to the optimal solution. The algorithm allows determining the parameters by setting diverse measurement resolutions with a relative uncertainty below 3.7% in 3 s. ZEMAX simulations of the sensor systems are performed with non-sequential mode to validate NP-GA determined system parameters. Simulation and computed results show the relative differences of the parameters dependent RMS radius of the laser spot on the image detector are below 0.35% and 8.72% in the x- and y-directions, respectively. © 2023 SPIE.

关键词： Genetic algorithms

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Design of Double-Loop Current Transformer Based on Magnetic Field Incomplete Cancellation

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CSEE Journal of Power and Energy Systems 2025年第2期11卷 772-782页

作者： Wenbo Li Xiaojun Tang Youshui Lu Ling Yan Yi Wu Mingzhe Rong Department of Measurement and Control Technology&Instrumentation School of Electrical EngineeringXi'an Jiaotong UniversityXi'an 710000China State Key Laboratory of Electrical Insulation&Power Equipment School of Electrical EngineeringXi'an Jiaotong UniversityXi'an 710000China

Electromagnetic current transformer is one of the important pieces of equipment used in AC power system measurement. Due to continuous improvement of current level to be measured in the power system, ordinary single-loop magnetic core structure cannot meet industrial needs of wide measuring range with high accuracy, while it even has a magnetic saturation problem when measured current is reaching the limit. Most existing methods expand measuring range and increase antisaturation ability of the magnetic core by either opening an air gap in the magnetic core or increasing number of turns of primary and secondary windings, but it will bring additional problems such as volume and heat dissipation of the transformer. To solve such issues, in this paper, we proposed a magnetic core structure of double-loop current transformer based on incomplete magnetic field cancellation principle. Calculation formula of air gap size and theoretical error are analyzed. We provide a theo-retical analysis of working characteristics, amplitude error and phase error throughout a three-dimensional simulation model of transformer. In addition, we evaluate performance through a series of comparison experiments. Results demonstrate our double-loop current transformer can maintain good linear relationship between primary and secondary current while ensuring measurement accuracy at 0.2 level. With the same volume, it has a wider range of rated current measurements and a certain anti-saturation ability.

关键词： Current difference coefficient double-loop core incomplete magneticfield cancellation

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Laser interference sensor for absolute shape and orthogonal vibration measurements in CNC machines

Laser interference sensor for absolute shape and orthogonal ...

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2021 International Conference on Optical Instruments and technology: Optoelectronic measurement technology and Systems

作者： Zhang, Hao Department of Measurement and Control Technology and Instrumentation Dalian Maritime University Dalian116026 China

ISBN: (纸本)9781510655690

An in-situ coordinate measurement sensor based on a Mach-Zehnder interferometer is presented in this work. The sensor system allows to simultaneously measure distance and velocity at fast rotating objects for inspecting vibrations, surface profile and absolute diameter of rotors in CNC machines. With a novel signal processing technique, in-situ, synchronized bi-directional vibration measurements are achieved directly at tool tip by using a single sensor with a measurement rate of 50 kHz at rotational speeds up to 300 Hz. Moreover, a novel line camera based sensor system is proposed with an extended measurement volume for submicron non-scan 3D shape measurements. © 2022 SPIE.

关键词： Vibration measurement

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Simultaneous two-dimensional velocity and distance measurements based on laser triangulation

arXiv

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arXiv 2024年

作者： Zhang, Hao Wang, Shiji Department of Measurement and Control Technology and Instrumentation Dalian Maritime University 1 Linghai Road Dalian116026 China

Laser triangulation sensors are widely used in industry for surface inspection due to simple setup, micron precision and low cost. Conventional laser triangulation methods only enable axial distance measurement limiting further applications, and their lateral resolution is limited by surface microstructure. For overcoming these issues, based on the geometric optics we propose novel theoretical models and methods to achieve lateral velocity measurement. Moreover, a novel axial distance measurement method using edge detection is presented, which can increase the lateral resolution by the order of one magnitude. The performance of the proposed methods are validated through simultaneous orthogonal velocity and distance measurements on a moving established metal specimen, showing the relative error and relative uncertainty can reach 10−4. The versatility of this multi degree of freedom measurement method paves the way for its broad application across all laser triangulation systems. Therefore, this simultaneous two-dimensional velocity and distance sensing approach can propel advancements in dynamic behavior discipline, including but not limited to motion mechanology and fluid mechanics. Copyright © 2024, The Authors. All rights reserved.

关键词： Degrees of freedom (mechanics)

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Study of Sub-Pixel Gray Degree Reconstruction Method for Simulation of Faint Star Element Target Position

SSRN

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SSRN 2023年

作者： Wu, Linghao Wang, Jiaan Jia, Wentao Zhang, Jian Sun, Jingrui Department of Measurement and Control Technology and Instrumentation Changzhou Institute of Technology Changzhou213032 China Key Laboratory of Space Precision Measurement Technology Chinese Academy of Sciences Xian710119 China State Key Laboratory of Optoelectronic Measurement Control and Optical Information Transmission Changchun University of Science and Technology Changchun130022 China

The simulation accuracy of the faint star element target (FSET) position is a key factor that affects the accuracy of the precision test of the star sensor. In order to solve the problem that the position accuracy of FSET is restricted by the size of its component elements, the mathematical representation of FSET position correction and the grayscale distribution of the component elements is derived, and the Gaussian radius and grayscale energy coefficient model of FSET is established. According to the measured distribution results of the position error of the full-field FSET, the gray distribution of the basic element is reconstructed by reconstructing each correction set to simulate FSET, and the correction accuracy of the sub-pixel level FSET position is realized. The experimental results show that, compared with the existing correction methods, the position accuracy of FSET is improved by 1.64 times after subpixel gray reconstruction. © 2023, The Authors. All rights reserved.

关键词： Pixels

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Design Method of Variable-Aperture Off-Axis Optical Integrator for Improving Irradiation Uniformity of Solar Simulator

SSRN

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SSRN 2023年

作者： Chen, Siwen Sun, Gaofei Liu, Shi Zhang, Guoyu Zhang, Jierui Chen, Jiali Key Laboratory of Opto-electronic Measurement and Optical Information Transmission Technology Ministry of Education Department of Instrumentation Science and Technology Changchun University of Science and Technology Changchun130022 China Institute of Aerospace Ground Simulation Test and Testing Technology Changchun University of Science and Technology Changchun130022 China Optical Measurement and Control Instrumentation Jilin Province Engineering Research Center Changchun130022 China

In order to improve the uniform light ability of optical integrator, a design method of variable diameter and off-axis optical integrator was proposed. Firstly, based on the theory of scalar diffraction, the factors affecting the ability of optical integrator to homogenize light were analyzed, and the structure of variable diameter and off-axis optical integrator was designed;Then, the relationship between the aperture and the arrangement of sub-eye lenses is explored by combining semi-definite programming theory and Lagrange-Helmholtz invariant. Finally, the optimal off-axis quantity of different ring strap eye lenses is determined from the perspective of geometric optics by using the aberration theory and following the principle of edge light, so as to achieve the improvement of the optical integrator's uniform light ability. The simulation results show that: On the effective irradiation surface ф26mm of the variable diameter off-axial integrator the irradiation non-uniformity is 2.0%, which decreases by 60% compared with the traditional integrator and reduces the system energy by 45%, which meets the energy utilization requirement of the optical integrator in the solar simulator. The homogenizing ability of optical integrator of solar simulator is improved on the premise that irradiation is not greatly affected and aspheric surface is not introduced. © 2023, The Authors. All rights reserved.

关键词： Irradiation

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Research on properties of alkali activated lead-zinc mineral powder cementitious materials 7

Research on properties of alkali activated lead-zinc mineral...

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2021 7th International Conference on Manufacturing technology and Applied Materials, ICAMMT 2021

作者： Yuan, Bicheng Gong, Weiting Chen, Sicheng Li, Peng Department of Composite Materials and Engineering Wuhan University of Technology Wuhan430070 China Department of Business Administration Wuhan University of Technology Wuhan430070 China Department of Measurement and Control Technology and Instrumentation Wuhan University of Technology Wuhan430070 China School of Entrepreneurship Wuhan University of Technology Wuhan430070 China

Cement has long been used as the main cementing material of the artesian paste filling material in the goaf of a mine, giving a generally high strength. However, the cement 'two grinding and one burning' process consumes a lot of energy, which aggravates the greenhouse effect. Therefore, a new type of cementitious material with lower energy consumption and lower emissions is needed. Solid wastes are useless by-products after mining and beneficiation, which are often dry piled in the open air, wasting land resources and polluting the environment. This project studied an alkali-activated mineral powder cementitious material, delineated its internal structure and morphology, and tested its mechanical properties. In a gelling system with 70% mineral powder, 30% Portland cement, 1% sodium silicate and a water-cement ratio of 0.4, the hydration reaction commenced the earliest and the early strength of the test block was the highest. In addition, further increasement in proportion of mineral powder or sodium silicate could not have a positive effect on the early strength of the system. © Published under licence by IOP Publishing Ltd.

关键词： Energy utilization

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Playback Method for Dynamic Star Map Simulation by Fusing Cosmic Background Radiation Information

SSRN

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SSRN 2024年

作者： Zhao, Bin Zhang, Yu Yang, Dongpeng Yang, Songzhou Zhang, Jian Sun, Gaofei Yao, Meng Ren, Taiyang Junjie, Yang Meng, XiangKai Zhang, Guoyu School of Optoelectronic Engineering Changchun University of Science and Technology Changchun130022 China State Key Laboratory of High Power Semiconductor Laser of Changchun University of Science and Technology Jilin Changchun130022 China Institute of Aerospace Ground Simulation Test and Testing Technology Changchun University of Science and Technology Changchun130022 China Optical Measurement and Control Instrumentation Jilin Province Engineering Research Center Changchun130022 China Key Laboratory of Opto-electronic Measurement and Optical Information Transmission Technology Ministry of Education Department of Instrumentation Science and Technology Changchun University of Science and Technology Changchun130022 China School of Life Science and Technology Changchun University of Science and Technology Changchun130022 China

In this study, a playback method for dynamic star map simulation fusing cosmic background radiation information was proposed to improve the playback speed of star maps. The image distortion effect before and after the fusion of star maps and cosmic background radiation was evaluated using peak signal-to-noise ratios. The performance of the proposed and the global catalog traversal generation algorithms without cosmic background radiation simulation capability, as well as the indicators, were experimentally compared. The results showed that the average refresh rates of the view cone filtering star map fast-generation algorithm and the fusion playback algorithm of the star map and cosmic background radiation were 74.2 and 73.7 Hz, respectively. Compared with the entire catalog traversal generation algorithm, the instantaneous stability of the single-frame star map was improved by 3.045 and 3.305 times, respectively, and the consumed time consistency was improved by 4.646 and 5.068 times, respectively. © 2024, The Authors. All rights reserved.

关键词： Image fusion

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