Journals >Optics and Precision Engineering
Contents
2024
Volume: 32 Issue 8
13 Article(s)
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[in Chinese]
Formation mechanism of Poisson's burr in micro-grooved diamond cutting of nickel-phosphorus alloy
Xiaopeng LI, Liangbao YU, Zhanwen SUN, and Sujuan WANG
In order to explore the formation causes and rules of Poisson's burr in ultra precision cutting of nickel-phosphorus alloy， and to seek a more accurate characterization method of Poisson's burr size， this paper conducted theoretical analysis of the formation mechanism of Poisson's burr in nickel-phosphorus In order to explore the formation causes and rules of Poisson's burr in ultra precision cutting of nickel-phosphorus alloy， and to seek a more accurate characterization method of Poisson's burr size， this paper conducted theoretical analysis of the formation mechanism of Poisson's burr in nickel-phosphorus alloy and established a prediction model for the height and width of Poisson's burr in orthogonal cutting process. Through experimental analysis of the influence of cutting parameters on the height and width of Poisson’s burr， it can be observed that the effect of cutting depth on burr size is significant. When the cutting depth increases from 3 ![]()
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Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1140 (2024)
Adaptive precision image stabilization control closed-loop method for space astronomical telescope
Quan ZHANG, Chuanxin WEI, Yuanpeng GAO, Yuji ZHU... and Dayi YIN|Show fewer author(s)
An adaptive closed-loop control method for precision image stabilization based on active optical technology was proposed to compensate for low-frequency LOS disturbances in space astronomical telescopes. The fine guide sensor （FGS） was used as a high-precision LOS disturbance detector， and the four-point supporting larAn adaptive closed-loop control method for precision image stabilization based on active optical technology was proposed to compensate for low-frequency LOS disturbances in space astronomical telescopes. The fine guide sensor （FGS） was used as a high-precision LOS disturbance detector， and the four-point supporting large-aperture fast steering mirror （FSM） mechanism drove by piezoelectric actuators（PZT） was used as a LOS disturbance compensator in this method. First， a PID controller was connected in series with an integral link for precise image stabilization closed-loop control to obtain the two-dimensional swing angles of the FSM required to compensate for the two-dimensional LOS disturbance detected by FGS. Furthermore， the expansion amount of each PZT was calculated through driving structure. Then， the feedforward compensation method based on generalized Bouc-Wen inverse hysteresis model was used for high-precision positioning control of the piezoelectric ceramic actuator. Finally， according to supervised Hebb learning rules， the single neuron with self-learning and adaptive abilities was used to adjust the PID controller parameters， thereby obtaining the optimal controller parameters. The experimental results show that the proposed control method can effectively compensate the LOS disturbance of the space astronomical telescope， and the integral value of PSD of the position error of the star point centroid in the X direction and Y direction of the FGS can be suppressed by 98.54% and 98.62% respectively in the frequency band of 0~6 Hz..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1153 (2024)
Inertial motion adaptive feedforward based base perturbation suppression for magnetic bearings
Yujie HUANG, Xiangbo XU, Lingbo ZHENG, and Lin LI
The rotor vibrations can be induced by the base motion in the active magnetic bearing systems. To solve this problem， a feedforward control approach based on inertial motion compensation was devised and implemented. First， a comprehensive five degrees of freedom dynamic model was formulated to describe the dynamics of The rotor vibrations can be induced by the base motion in the active magnetic bearing systems. To solve this problem， a feedforward control approach based on inertial motion compensation was devised and implemented. First， a comprehensive five degrees of freedom dynamic model was formulated to describe the dynamics of a magnetically suspended rotor in the active magnetic bearing system with the base movement. Then， the rotor dynamics with various disturbance forces during small-amplitude complex base motions were analyzed. Subsequently， an innovative inertial feedforward method employing an adaptive algorithm was proposed. Finally， to verify the effectiveness of the proposed control method， an experiment platform was built， and then experimental investigations were carried out to compare the rotor's response to various disturbances both before and after activating the feedforward controller. The experimental results show that the implementation of the proposed feedforward control method led to an about 80% reduction of the vibration displacement of the magnetically suspended rotor when it is subjected to base motion perturbations. This marked reduction in displacement significantly enhanced the operational precision of the magnetically suspended rotor. Furthermore， the hardware implementation of the feedforward control method only need the addition of a compact inertial micro-electromechanical measurement unit. This small hardware addition meets some requirements for engineering applications， especially where there is very small space for the mechanical structure. In conclusion， the proposed inertial motion feedforward control method demonstrates promising ability in effectively reducing the vibration displacements of the magnetically suspended rotor disturbed by the base motion， and this can improve the operational stability and precision of active magnetic bearing systems while only a very small inertial measurement unit is added..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1164 (2024)
[in Chinese]
Axis alignment and error analysis of a novel rotating laser-scanning system
Yongjie REN, Wei GUO, Tengfei WU, Mingxin TENG... and Jigui ZHU|Show fewer author(s)
The rotating laser-scanning system is a spatial multi-target parallel angle sensing system， which is based on a precision turntable and combined with multiple lasers. To improve the performance of the system's light source， a new type of axis structure was designed that uses optical fibers to import light sources fThe rotating laser-scanning system is a spatial multi-target parallel angle sensing system， which is based on a precision turntable and combined with multiple lasers. To improve the performance of the system's light source， a new type of axis structure was designed that uses optical fibers to import light sources from the outside. However， when the laser passes through the hollow rotating shaft and enters the reflector group at a certain angle， if the incident cylindrical lens is tilted， the scanning light surface pattern will change.To address this problem， a method for adjusting the attitude of the laser optical axis based on the transmissivity of parallel lines was studied. With the help of a laser tracking measurement platform， individual fittings were performed for the optical axis and the rotational axis system. A calibration method for the tilt error of the optical axis was established.The experimental results demonstrate that the spatial angle between the adjusted optical axis and the rotational axis exceeds 0.15°， fully satisfying the angular requirements for laser incidence on the cylindrical lens in terms of the central linearity of the light cross-section.This adjustment scheme is applicable to the assembly phase of the system， enabling the scanned light to approach an ideal plane more closely. This contributes to the enhancement of the system's measurement accuracy..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1111 (2024)
High-speed rotating-mirror Q-switched Er，Cr：YSGG nanosecond narrow pulse laser at 2.79 μm
Yongbin ZHU, Shengjie MA, Tingqing CHENG, Li WANG... and Haihe JIANG|Show fewer author(s)
Rotating mirror Q-switched technology incurs no intracavity insertion loss， making it a direct method for obtaining narrow pulses and high peak power output lasers. Nanosecond pulses require the use of high-speed rotating mirror Q-switch， along with precise control of motor speed and xenon lamp discharge delay. This enRotating mirror Q-switched technology incurs no intracavity insertion loss， making it a direct method for obtaining narrow pulses and high peak power output lasers. Nanosecond pulses require the use of high-speed rotating mirror Q-switch， along with precise control of motor speed and xenon lamp discharge delay. This ensures maximum population inversion of in the laser medium， leading to the highest laser energy output. This paper presented the design of a high-speed rotating mirror Q-switched control system with the Arduino Mega 2560 microcontroller as its core. The system utilized precise parse of serial screen instructions by the microcontroller to control the charging and discharging of the laser power supply and the start-stop operations of the high-speed motor. Additionally， it integrated and downshifted the pulse signals from the rotating mirror to control the precise delay time for triggering the xenon lamp discharge， thereby achieving precise control over the delay time for the nanosecond narrow pulse Q-switched output of the lamp-pumped Er，Cr：YSGG laser. The highest single-pulse laser energy of 45.7 mJ， pulse width of 86.2 ns， and corresponding peak power of 530.2 kW were obtained at a repetition frequency of 5 Hz with a rotating mirror speed of 650 r/s..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1122 (2024)
Wrapping phase repair method based on Tsallis Relative Entropy evaluation
Leqian KANG, Pengcheng YANG, Qiujuan LÜ, Liping LIAN, and Xindong ZHU
In the laser interferometric measurement of gear tooth flank topography， the collected wrapped phase map can be influenced by various sources of noise. These areas of poor phase quality in the wrapped phase map can lead to unwrapping errors and reduces measurement accuracy. This paper proposed a wrapped-phase repair meIn the laser interferometric measurement of gear tooth flank topography， the collected wrapped phase map can be influenced by various sources of noise. These areas of poor phase quality in the wrapped phase map can lead to unwrapping errors and reduces measurement accuracy. This paper proposed a wrapped-phase repair method to address the problem. It utilized Tsallis relative entropy as an evaluation criterion， based on the probability distribution characteristics of the interference fringe image. The method first fitted the thresholded image using Gaussian distribution， then evaluated the phase quality by Tsallis relative entropy， finally patched the poor quality regions to improve the quality of phase unwrapped. The experimental results show that the method can reduce the phase residue points by 40% and effectively improve the phase quality. The proposed method is user-friendly and highly accurate. It can be applied to other fields related to phase-shifting optics..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1130 (2024)
[in Chinese]
Monocular vision transmission line sag measurement method based on local photography
Guanhua HU, Chenghui SUN, Liqun SHEN, and Tao HU
Regular monitoring of the size of wire sag in transmission lines is of great significance for the stable operation of transmission lines. The traditional sag measurement method is complex and time-consuming， and obtaining a complete wire image using monocular vision is a convenient sag measurement method. However， whenRegular monitoring of the size of wire sag in transmission lines is of great significance for the stable operation of transmission lines. The traditional sag measurement method is complex and time-consuming， and obtaining a complete wire image using monocular vision is a convenient sag measurement method. However， when the span of the transmission line is too large， the camera is limited by the field of view angle and resolution， making it difficult to capture the complete wire and measure the sag. To address the above issues， a convenient and usable local photogrammetry method was designed， which combines the accelerometer sensor in the IMU with a high-resolution industrial monocular camera. With a small amount of transmission line parameters known， only the left part of the tested wire needs to be photographed. After obtaining a single wire image， semantic segmentation technology was introduced to extract the wires in the image. Based on the photogrammetric model， the actual points of the wires were connected to the corresponding imaging points， and a nonlinear equation system was established. After nonlinear solving， the three-dimensional shape of the wires was restored， and then the wire sag was calculated. The relative error of sag measurement can be controlled within 5%， meeting practical application requirements..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1175 (2024)
Gas leakage detection based on spatiotemporal information of low contrast infrared images
Jinhui ZUO, Wenbin XU, Shijie ZHOU, Daobin SHENG... and Lei ZHANG|Show fewer author(s)
The hazards caused by gas leakage accident are multifaceted， such as environmental pollution， personnel and property loss， fire and explosion. Thermal infrared imaging is widely used as a qualitative detection technology that can realize large-scale and fast imaging. However， compared with general infrared image， the cThe hazards caused by gas leakage accident are multifaceted， such as environmental pollution， personnel and property loss， fire and explosion. Thermal infrared imaging is widely used as a qualitative detection technology that can realize large-scale and fast imaging. However， compared with general infrared image， the contrast of gas cloud infrared image is lower， the edge is more blurred， and it’s hard to detection. To solve this problem， this article proposed a leak detection method for low contrast gas infrared images based on mixed Gaussian background modeling. Firstly， in the preprocessing stage， time-domain adaptive interframe filtering algorithm was proposed to realize noise reduction and detail maintenance of infrared images. Then， based on spatial information and gradient information constraints， a spatiotemporal mixed Gaussian background model was proposed to achieve preliminary extraction of the foreground of leaked gas targets. Finally， to better remove interfering moving targets in foreground detection， an improved fast and robust fuzzy C-means clustering method was used to realize adaptive segmentation of gas regions. The experimental results show that at the leakage distance of 5 m， this detection algorithm can effectively improve accuracy， compensate for the problems of gas region voids， and reduce interference from other moving objects. The accuracy of gas leakage detection is between 92.3% and 96.3%， which has significant anti-interference and region segmentation capabilities compared to other algorithms..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1186 (2024)
Sand microscopic image segmentation with enhanced tuna swarm optimization exponential entropy
Mengfei WANG, Weixing WANG, Kun XU, and Limin LI
Microscopic image segmentation of sand grains can assist geological assessment， but it poses challenges to the accuracy of segmentation due to its variety and complex features. For such images， a segmentation method with enhanced tuna swarm optimization exponential entropy （ETSO-EXP） was proposed， which could effectiveMicroscopic image segmentation of sand grains can assist geological assessment， but it poses challenges to the accuracy of segmentation due to its variety and complex features. For such images， a segmentation method with enhanced tuna swarm optimization exponential entropy （ETSO-EXP） was proposed， which could effectively preserve the texture features of various sand grains. First of all， aiming at some deficiencies of the tuna swarm optimization （TSO） algorithm in global search and local development， a chaotic disturbance strategy， a dynamic weight strategy and a cosine disturbance strategy were proposed to enhance it. The benchmark function experiment showed that the ETSO greatly improved the convergence accuracy and slightly increased the convergence speed. Secondly， the ETSO algorithm was used to determine the segmentation threshold of the EXP， and the feasibility of the scheme was verified by taking the information content of the segmented image as the standard. Finally， a segmentation experiment was carried out on the Yarlung Zangbo River sand microscopic image dataset. Compared with the TSO-EXP， the image of the ETSO-EXP segmentation has a better peak signal-to-noise ratio， structural similarity， feature similarity and the optimization speed has been improved by 18.78%， 6.85%， 4.16% and 3.83%， respectively， and the performance is the best among the similar segmentation methods. The results show that the segmentation method with the ETSO-EXP has high segmentation accuracy and calculation speed for images with high contrast， rich texture or large differences in the size of sand debris..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1199 (2024)
Real-time urban street view semantic segmentation based on cross-layer aggregation network
Zhiqiang HOU, Minjie CHENG, Sugang MA, Minjie QU, and Xiaobao YANG
With the rapid development of autonomous driving technology， precise and efficient scene understanding has become increasingly important. Urban street scene semantic segmentation aims to accurately identify and segment elements such as pedestrians， obstacles， roads， and signs， providing necessary road information for aWith the rapid development of autonomous driving technology， precise and efficient scene understanding has become increasingly important. Urban street scene semantic segmentation aims to accurately identify and segment elements such as pedestrians， obstacles， roads， and signs， providing necessary road information for autonomous driving technology. However， current semantic segmentation algorithms still face challenges in urban street scene segmentation， mainly manifested in issues such as insufficient discrimination between different categories of pixels， inaccurate understanding of complex scene structures， and inaccurate segmentation of small-scale objects or large-scale structures. To address these issues， this paper proposed a real-time urban street scene semantic segmentation algorithm based on a cross-layer aggregation network. Firstly， a pyramid pooling module combined with cross-layer aggregation was designed at the end of the encoder to efficiently extract multi-scale context information. Secondly， a cross-layer aggregation module was designed between the encoder and decoder， which enhances the representation ability of information by introducing a channel attention mechanism and gradually aggregates the features of the encoder stage to fully achieve feature reuse. Finally， a multi-scale fusion module was designed in the decoder stage， which aggregates global and local information in the channel dimension to promote the fusion of deep and shallow features. The proposed algorithm was validated on two common urban street scene datasets. On an RTX 3090 graphics card （TensorRT speed measurement environment）， the algorithm achieves 73.0% mIoU accuracy on the Cityscapes test set with real-time performance of 294 FPS， and 75.8% mIoU accuracy on higher resolution images with real-time performance of 164 FPS； on the CamVid dataset， it achieves 74.8% mIoU accuracy with real-time performance of 239 FPS. Experimental results show that the proposed algorithm effectively balances accuracy and real-time performance， significantly improving semantic segmentation performance compared to other algorithms， and bringing new breakthroughs to the field of real-time urban street scene semantic segmentation..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1212 (2024)
Improving the lightweight VTG-YOLOv7-tiny for steel surface defect detection
Liming LIANG, Pengwei LONG, Yao FENG, and Baohe LU
To address the problems of diverse and complex shapes of steel surface defects， detection target missing， and large number of algorithm parameters， a lightweight VTG-YOLOv7-tiny steel defect detection algorithm was proposed. The method first designed VoVGA-FPN network to reduce the loss of information during informatioTo address the problems of diverse and complex shapes of steel surface defects， detection target missing， and large number of algorithm parameters， a lightweight VTG-YOLOv7-tiny steel defect detection algorithm was proposed. The method first designed VoVGA-FPN network to reduce the loss of information during information transmission and enhance the network feature fusion ability； second， it constructed a triple coordinate attention mechanism to improve the model's feature extraction ability of spatial and channel information； third， it introduceed ghost shuffle convolution to reduce the model parameters and computation while improving the accuracy； fourth， it added a large target detection layer to improve the problem that some defects in the feature map occupy a large proportion， resulting in low detection accuracy. The improved algorithm was verified on the NEU-DET and Severstal steel defect datasets. Compared with the original model， the mAP of the improved algorithm is increased by 5.7% and 8.5%， respectively； the parameters and computation are reduced by 0.61 M and 4.2 G， respectively； the accuracy and recall are increased by 7.1%， 1.8% and 8.9%， 7.0%， respectively. The experimental results show that the improved algorithm better balances the detection accuracy and lightweight， and provides a reference for edge terminal devices..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1227 (2024)
Dense control valve parts dataset for industrial object detection
Linyi WANG, Jing BAI, Yanmei LI, and Wenjing LI
Automated intelligence in industrial production is inseparable from automatic object detection， and high-accuracy automatic object detection relies on datasets adapted to the actual scene. This article published a dense control valve parts dataset for industrial practical scenarios， named PD4CV （Part Detection for ContAutomated intelligence in industrial production is inseparable from automatic object detection， and high-accuracy automatic object detection relies on datasets adapted to the actual scene. This article published a dense control valve parts dataset for industrial practical scenarios， named PD4CV （Part Detection for Control Valve） 2023. The image of this dataset came from the control valve production workshop， and after the image collection was completed， it underwent steps such as dataset preprocessing， dataset annotation， and dataset partitioning. The images of this dataset were all from the control valve production workshop. After the image collection was completed， the dataset images were first preprocessed， followed by labeling the part targets in the dataset images. Then， the dataset images were divided into training， validation， and testing sets. The PD4CV2023 dataset covered a total of 9 types of parts， including 510 workstation images and 15 015 part samples， with an average of approximately 29 part samples per image. Compared with the existing object detection datasets， this dataset had the characteristics of dense placement and occlusion of parts， large size differences of parts， similar shapes of some parts， and unbalanced number of parts samples. Finally， pre training comparative experiments on different types of datasets show that general scenario datasets and specific industrial scenario datasets are only suitable for general and specific tasks， while the PD4CV2023 dataset， which represents the actual production conditions of control valves， can be used for target detection of control valve parts， and has its particularity and irreplaceability； a comprehensive comparison of a series of algorithms on this dataset verifies the effectiveness of PD4CV2023 dataset in general object detection， multi-scale object detection， and object detection under small-scale and imbalanced data. The PD4CV2023 dataset can be used for research on industrial oriented object detection algorithms..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1241 (2024)
Adaptive Discontinuity Segmentation in Phase Measurement
Gaoxu DENG, Zihao LIU, Liying KE, Shiyang ZHOU, and Lidong MA
To mitigate the impact of discontinuous positions on the accuracy of three-dimensional reconstruction using phase measurement profilometry， we introduced an adaptive segmentation method. This method was based on phase measurement and employed a phase discontinuity segmentation algorithm utilizing adaptive orientation cTo mitigate the impact of discontinuous positions on the accuracy of three-dimensional reconstruction using phase measurement profilometry， we introduced an adaptive segmentation method. This method was based on phase measurement and employed a phase discontinuity segmentation algorithm utilizing adaptive orientation coherence.Initially， we employed the adaptive orientation coherence map and the smooth phase map to identify discontinuous positions， that was， the grayscale map of the discontinuous area and the continuous area was obtained. Subsequently， the grayscale map was processed into a binary mask， representing discontinuous areas as 0 and continuous areas as 1. Lastly， this mask map served as a weight map in the weighted least squares phase unwrapping method to convert the relative phase into an absolute phase. The resulting weight primarily assessed the phase quality at each pixel position within the wrapped phase map.The simulation results show that the segmentation mean errors of the adaptive orientation coherence method for discontinuities of straight lines and rectangles in the wrapped phase map with noise variance of 0.8 are 1.678 3 and 3.000 2 pixels， respectively.The actual experiment also proves that the proposed method can effectively segment the discontinuities for high-precision 3D reconstruction..
Optics and Precision Engineering
- Publication Date: Apr. 25, 2024
- Vol. 32, Issue 8, 1252 (2024)
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