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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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Displacement equation-free laser triangulation ranging with deep learning

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Optics Express 2025年第12期33卷 26607-26615页

作者： Hao Zhang Jiaxing Zhong Shiji Wang Department of Measurement and Control Technology and Instrumentation Dalian Maritime University Dalian 116026 China

The measurement accuracy of laser triangulation ranging systems is easily affected by errors in system structure parameters, due to the asymmetric structure of the systems. This work proposes an intelligent laser triangulation ranging method that significantly reduces dependence on system parameters to increase measurement accuracy. Firstly, a nonlinear programming genetic algorithm with an elitist strategy is employed to design a laser triangulation ranging system. A deep neural network is then established for distance estimation without using the system structure parameters based displacement equations. Experimental results demonstrate this deep learning based laser triangulation ranging method can reduce the nonlinear error by the order of one magnitude, compared with the conventional method of using displacement equations. Meanwhile, the root mean squared error and the mean absolute error are reduced by factors of 5 and 3 to sub micron, respectively, which is no longer influenced by the design and setting errors of system structure parameters.

关键词： Deep learning Genetic algorithms Laser imaging Neural networks Structured light Systems design

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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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Higher Linearity and Low Noise DC Amplifier With Current Mirror Linear Compensation Structure in Digital Multimeter

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IEEE Transactions on instrumentation and measurement 2025年 74卷

作者： Wang, Shilong Wang, Hengbo Deng, Shoupeng Wei, Jianrong Li, Tuo Gao, Hanlin Zhang, Jialin Liu, Fei Dang, Dianbang Wang, Yanzhang Jilin University State Key Laboratory of Deep Earth Exploration and Imaging College of Instrumentation and Electrical Engineering Department Changchun130061 China Beijing Aerospace Measurement and Control Technology Company Ltd. Beijing100000 China Qinghai Huanghe Mining Company Ltd. Qinghai Xining810016 China

The high-linearity and low noise amplifier has been developed as a core module to improve the testing accuracy and weak signal capture ability of the high-precision digital multimeter. This article focuses on optimizing the linearity and noise of the dc amplifier by using the nonlinearity of the current mirror to compensate for junction field-effect transistor (JFET) mismatch. This effectively suppresses the second-order nonlinearity caused by JFET mismatch and results in a high-linearity parameter model. The device noise of the dc amplifier is carefully selected and optimized under this high-linearity model. The experiment shows that under linear fitting, the nonlinear errors of the dc amplifier are 15, 9, and 4 ppm for input voltages of 0.1, 1, and 10 V, respectively. This is a significant improvement compared to the nonlinear errors before optimizing the current mirror structure, which were reduced by 100 times. The linear fitting error of the dc amplifier is now less than that of the Keysight 37740A. The white noise of the dc amplifier is also improved, with a value of less than 6 nV/Hz1/2 , and the peak-to-peak noise is now 282 nV, which is equivalent to the noise performance of the Keysight 37740A. Under third-order polynomial fitting, the nonlinear errors of the dc amplifier are 5, 4.8, and 0.5 ppm for input voltages of 0.1, 1, and 10 V, respectively. This is comparable to the linearity performance of the Fluke 8508A. The peak-to-peak noise of the amplifier after average processing is also equivalent to the noise performance of the Fluke 8508A. © 1963-2012 IEEE.

关键词： White noise

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