Journals >Optics and Precision Engineering
Contents
2022
Volume: 30 Issue 12
12 Article(s)
Export citation format
Information Sciences
Vehicle detection based on FVOIRGAN-Detection
Hao ZHANG, Jianhua YANG, and Haiyang HUA
To solve the problem of spatial information loss in point cloud processing， and extract the texture information of visible images to the maximum extent during the fusion， a vehicle detection method based on laser point cloud and visible image fusion is proposed. The point cloud processing idea of front views based on tTo solve the problem of spatial information loss in point cloud processing， and extract the texture information of visible images to the maximum extent during the fusion， a vehicle detection method based on laser point cloud and visible image fusion is proposed. The point cloud processing idea of front views based on the original information is incorporated into the CrossGAN-Detection method. The point cloud is projected to the front view angle， and each dimension of the original point cloud information is sliced into feature channels， significantly improving the utilization efficiency of the point cloud information without reducing network performance. The idea of relative probability is introduced， and the relative real probability， instead of the absolute real probability， of the discriminator is used to identify the image such that the texture information extracted is fused. The experimental results show that the AP indexes of this method in the three categories of easy， medium， and difficult of KITTI dataset are 97.67%， 87.86%， and 79.03% respectively. In a scene with limited light， the AP index reaches 88.49%， which is 2.37% higher than that of the CrossGAN-Detection method. Hence， target detection performance is improved..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1478 (2022)
Lightweight Mars remote sensing image super-resolution reconstruction network
Mingkun GENG, Fanlu WU, and Dong WANG
A lightweight Laplacian pyramid image super-resolution reconstruction convolution neural network based on deep Laplacian pyramid networks （LapSRNs） is proposed to accommodate the numerous parameters used in super-resolution reconstruction methods based on deep learning. First， shallow features are embedded from the inpA lightweight Laplacian pyramid image super-resolution reconstruction convolution neural network based on deep Laplacian pyramid networks （LapSRNs） is proposed to accommodate the numerous parameters used in super-resolution reconstruction methods based on deep learning. First， shallow features are embedded from the input low resolution image （LR） input. Subsequently， using recursive blocks that allow parameter sharing and contain shared-source skip connections， deep features are extracted from the shallow features. Additionally， residual image （RI） containing high-frequency information is inferred. Next， the RI and input LR are upsampled via a transposed convolutional layer and added pixel by pixel to obtain a super-resolution image. The total number of parameters used in this method is only 3.98% of that used in the LapSRN for three scales， and the peak signal to noise ratio index increases by 0.031 3 and 0.116 7 dB under 4 times and 8 times super-resolutions， respectively. The proposed method reduces the number of parameters by 81.6%， 90.8%， and 88.8% under 2 times， 4 times， and 8 times resolutions， while the super-resolution effect is maintained..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1487 (2022)
Improved CycleGAN network for underwater microscopic image color correction
Haotian WANG, Qingsheng LIU, Liang CHEN, Wangquan YE... and Ronger ZHENG|Show fewer author(s)
The absorption and scattering of light by marine water and suspended particles lead to the distortion of color in underwater microscopic images. This paper presents an improved cycle generative adversarial network （CycleGAN） algorithm for effectively correcting the color of microscopic images of underwater targets. TheThe absorption and scattering of light by marine water and suspended particles lead to the distortion of color in underwater microscopic images. This paper presents an improved cycle generative adversarial network （CycleGAN） algorithm for effectively correcting the color of microscopic images of underwater targets. The structural similarity index （SSIM） loss function， which measures the loss of color information among images， of the R， G， and B channels was added between the original underwater images and the reconstructed images. Therefore， the color of the R， G and B channels was accurately regulated. This enhanced not only the overall performance of the CycleGAN， but also the quality of images produced by the generator. Subsequently， the improved network was trained by using a training data set， which consisted of underwater multicolor self-made target images and microscopic images of natural stones. The trained network model was used to correct the color of the microscopic images of underwater stones. The results showed that the improved CycleGAN algorithm had distinct advantages in color correction over other methods. The peak signal-to-noise ratio and SSIM of the images processed by using this algorithm were 41.85% and 35.62% higher than those processed by using the traditional Retinex algorithm， respectively. Moreover， in terms of subjective vision， the corrected underwater microscopic images had the highest color similarity with the images taken in air. In conclusion， this method can effectively correct the color of underwater target images and improve the quality of underwater microscopic images. It can be applied in marine geology and marine biology..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1499 (2022)
Infrared multi-target dual-station positioning based on maximum density estimation in track direction
Juan YUE, Fanming LI, and Sili GAO
This study aims to reduce the influence of measurement errors on the positioning of a multi-target in dual-stations. By using the spatio-temporal distribution characteristics of the motion track points of a target over a short time period， an infrared motion multi-target dual-station positioning method is proposed baseThis study aims to reduce the influence of measurement errors on the positioning of a multi-target in dual-stations. By using the spatio-temporal distribution characteristics of the motion track points of a target over a short time period， an infrared motion multi-target dual-station positioning method is proposed based on the maximum track density estimation. First， single frame multi-target matching is performed based on the elevation difference along direction-finding rays of dual-stations. Then， based on the two-dimensional direction histogram， the target track direction is preliminarily estimated， following which the maximum density of the target track direction is determined based on the mean shift. Finally， the authenticity of the track point is validated based on the target track direction to reduce the influence of measurement errors on the target positioning result. The experimental results reveal that the proposed method effectively eliminates the mismatch point and reduces the error deviation point. The maximum fit error of the track is less than 0.5 m， and the average fit error is less than 0.3 m， which represent improvements on existing algorithms. For targets that exhibit both mismatched points and larger error deviations compared with those of the histogram method， the maximum fitting error of the proposed method is reduced by more than 50%， and the average fitting error is reduced by 27%. Thus， the proposed method can effectively reduce the positioning error， which has important applications in military and civilian fields， such as three-dimensional positioning， target prediction， and hooting training evaluation..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1509 (2022)
Micro/Nano Technology and Fine Mechanics
Carbon fiber thin-walled cylindrical support structure between primary and secondary mirror in space camera
Xunpeng SONG, Xiaoxue GONG, Lei ZHANG, Jian YUAN, and Yunfei YANG
In large-aperture and long-focus space remote sensing cameras， the relative position changes between the primary and secondary mirrors affect the imaging quality and stability of the camera. The support structure between the primary and secondary mirrors， that is the bearing structure between them， is integral for the In large-aperture and long-focus space remote sensing cameras， the relative position changes between the primary and secondary mirrors affect the imaging quality and stability of the camera. The support structure between the primary and secondary mirrors， that is the bearing structure between them， is integral for the camera design process. In this study， a carbon fiber thin-walled cylindrical support structure between the primary and secondary mirrors was designed， based on the characteristics of large-aperture and long-focus cameras. First， the cylindrical base structure was selected depending on the optical system considered. Then， based on the characteristics of the cylindrical base structure， the geometric structure of the secondary mirror support beam and the longitudinal reinforcement ribs of the cylindrical structure were analyzed and selected in sequence. Subsequently， to fully utilize the design characteristics of the carbon fiber material layup， the iterative design optimization of the key size of the support structure， thickness of the layup， and angle of the layup was performed， and the design results were analyzed by conducting finite element simulations. Finally， the stability and structural rigidity of the support structure were verified by measuring the change in the angle of the secondary mirror and conducting the characteristic-level sweep frequency vibration test. The results indicated that the differences in long-term monitoring under the same conditions for the secondary mirror was less than 1.5"， change before and after gravity flipping was less than 1.08"， first-order natural frequency of the supporting structure was greater than 115 Hz， and axial frequency was greater than 180 Hz. Thus， the support structure between the primary and secondary mirrors exhibited excellent rigidity and structural stability， satisfying the requirements of the design index..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1429 (2022)
Multi-source heterogeneous information acquiring test experiment and platform construction for CNC machine tool
Xiaolei DENG, Yushen CHEN, Shupeng GUO, Jiacong ZHENG, and Xiaobo SHENG
Considering the actual demand for multi-information and multi-signal acquisition for CNC machine tool working process spindle systems， a multi-source heterogeneous information acquisition test platform comprising multi-type sensors was designed and developed. The platform consists of a hot state characteristic informatConsidering the actual demand for multi-information and multi-signal acquisition for CNC machine tool working process spindle systems， a multi-source heterogeneous information acquisition test platform comprising multi-type sensors was designed and developed. The platform consists of a hot state characteristic information acquisition system and dynamic information acquisition system for machine tools. The hot state characteristic information acquisition system monitors the displacement and temperature data of each point of the CNC machine tool while the dynamic information acquisition system monitors the vibration， stress， and strain at each point of the machine tool. Based on the simulation analysis of the spindle system， the test platform was first constructed in this study， and subsequently， multi-source heterogeneous information acquisition tests at speeds of 2000， 3000， and 4000 r/min were conducted. The relative error between the test and simulation results was within 10%. Simultaneously， the collected data were preprocessed and fused to model the thermal error of the multi-source information. The root mean square error of the thermal deformation after thermal equilibrium was less than 0.9 μm at the corresponding rotational speed and the determination coefficient was above 0.9. This indicated that the multi-source heterogeneous information acquisition test platform built possessed better accuracy at multi-rotational speeds. The experimental platform and data acquisition fusion method described in this study provide an important technical means and theoretical basis for the thermal error compensation and thermal design of machine tools..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1440 (2022)
Design and process test of h-shaped magnetic composite fluid polishing tool
Chen JIANG, Jian LIU, Jiuxiang WEI, and Jianfei LAN
To overcome the technical problems of low finishing efficiency and quality of the inner wall of deep holes， an auxiliary magnetic field block was added to the traditional needle-type magnetic compound fluid （MCF） polishing tool head. In addition， an MCF deep hole polishing tool and processing method based on the h-shapTo overcome the technical problems of low finishing efficiency and quality of the inner wall of deep holes， an auxiliary magnetic field block was added to the traditional needle-type magnetic compound fluid （MCF） polishing tool head. In addition， an MCF deep hole polishing tool and processing method based on the h-shaped polishing tool head are proposed. COMSOL Multiphysics was used to establish a combined model of permanent magnet magnetic field， and the head structure of the h-shaped polishing tool was designed with a uniform magnetic field. MCF deep hole polishing magnetic field model and flow field model were established， and magnetic-fluid coupling simulation was conducted to analyze the MCF fluid flow characteristics. Considering brass H62 as the sample material， experiments with different polishing process parameters were carried out. Further， the surface morphology， roughness， and material removal rate of the sample before and after polishing were compared， and the simulation model was verified. The experimental results suggest that the best polishing effect is obtained when the horizontal distance between the two magnets of the h-shaped polishing tool head is 8 mm， polishing speed is 1400 r/min， polishing gap is 1 mm， particle size of the alumina abrasive grain is 0.5 µm， surface roughness is 173 nm， and material removal rate is 0.84 mg/min； in addition， under these conditions， the polishing effect produced by the h-shaped polishing tool head is better than that produced by the needle polishing tool head. The MCF deep hole polishing method proposed herein can effectively improve the surface quality of the inner wall of the hole. In addition， the proposed method is effective and can lay the foundation for subsequent applications..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1452 (2022)
General-purpose temperature sensitive point combination selection for thermal error of machine tool spindle
Linfeng ZHOU, Guoqiang FU, Zhengtang LI, Guoqiang LEI, and Xiaolei DENG
A general temperature-sensitive point combination selection method based on the automatic determination of the points is proposed in this paper to solve the problem of selecting sensitive points depending on manual experience. First， the absolute mean correlation coefficients between temperature variables and thermal eA general temperature-sensitive point combination selection method based on the automatic determination of the points is proposed in this paper to solve the problem of selecting sensitive points depending on manual experience. First， the absolute mean correlation coefficients between temperature variables and thermal errors are calculated for selecting the temperature points most related to the thermal errors as sensitive points. Second， the temperature point with the largest absolute mean correlation coefficient is considered as the initial clustering center of the K-Means++ clustering algorithm， and a series of temperature-sensitive points with different numbers is selected. Subsequently， a backpropagation neural network thermal error model is established by using a series of sensitive point combinations and thermal errors as input， and the temperature-sensitive point combinations with the best prediction performance are selected based on evaluation indexes. Finally， the validity of the optimal temperature-sensitive point combination for the same error terms under different working conditions and different error terms under the same working conditions and the universality of different thermal error models are verified by employing the VMC850 CNC machine tool. The results show that the combined selection method of temperature-sensitive points proposed in this paper is suitable for experimental data under different working conditions and exhibits good versatility in different thermal error models..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1462 (2022)
Modern Applied Optics
Adaptive stochastic resonance detection of weak light signal in underwater laser communication
Jianlei ZHANG, Xiang LAN, Yi YANG, Fengtao HE, and Yunzhou ZHU
In underwater optical wireless communication （UOWC） systems， the low signal-to-noise ratio causes received optical signals to be submerged in strong noise. To solve this problem， a detection method for underwater weak optical signals based on adaptive stochastic resonance （ASR） is proposed. In this study， the characterIn underwater optical wireless communication （UOWC） systems， the low signal-to-noise ratio causes received optical signals to be submerged in strong noise. To solve this problem， a detection method for underwater weak optical signals based on adaptive stochastic resonance （ASR） is proposed. In this study， the characteristics of underwater weak light signals and the detection mechanism of stochastic resonance are analyzed. The concept of twice sampling is introduced to enable the application of stochastic resonance to optical signal detection at any frequency. Additionally， the parameters that affected the stochastic resonance system are evaluated， and a detection method combining the improved ant colony algorithm and stochastic resonance is proposed. The system dynamically adjusts the system parameters based on the detection performance， such that the entire system achieves the optimal matching state to realize ASR. To verify the effectiveness of the method， a UOWC experimental system based on an avalanche photodiode is built. The experimental results show that the bit error rate is 5×10-4 when SNR=-4.559 5 dB. Thus， underwater weak light signal detection based on ASR is proved to significantly improve the bit error rate performance of UOWC receivers..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1383 (2022)
Orbital angular momentum detection of vortex beam based on soft-edge aperture
Jingqiu ZHUANG, Han XIONG, Tiancheng YU, Jing CHEN, and Jinhu ZHENG
The orbital angular momentum propagated by a vortex beam is very important in free-space optical communication. In this study， a soft-edged aperture was used to improve the orbital angular momentum detection technology of a vortex beam based on aperture diffraction. The Fresnel diffraction of soft-edged apertures has aThe orbital angular momentum propagated by a vortex beam is very important in free-space optical communication. In this study， a soft-edged aperture was used to improve the orbital angular momentum detection technology of a vortex beam based on aperture diffraction. The Fresnel diffraction of soft-edged apertures has a certain degree of convergence compared with hard-edged apertures. This can increase the relative intensity of the primary bright spots to the secondary bright spots in far-field diffraction distribution， thereby improving the recognizability of the primary bright spots and expanding the range of orbital angular momentum based on aperture diffraction. The best detection effect was achieved using the primary and secondary bright spots intensity contrast values in far-field diffraction and the peak and trough intensities average contrast values in the primary bright spot area under the appropriate super-gaussian orders. By combining theoretical simulations and experiments， it can be seen that the use of rectangular soft-edged apertures can further increase the detection range of vortex optical topological charges from the 20th order to the 30th order， and the use of triangular soft-edged apertures can increase the detection range from the ±10th order to ±20th order..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1394 (2022)
MEMS fiber optic acoustic sensor and performance testing method based on ultra-small GRIN fiber lens
Chi WANG, Wei CHEN, Jianmei SUN, Yuancheng ZHENG, and Feilu CHEN
Research is conducted on a micro-electromechanical system （MEMS） fiber optic acoustic sensor by combining an MEMS diaphragm and ultra-small graded-index （GRIN） fiber optic lens， and a performance test method of the MEMS fiber optic acoustic sensor based on the swept-source optical coherence tomography （SS-OCT） demodulaResearch is conducted on a micro-electromechanical system （MEMS） fiber optic acoustic sensor by combining an MEMS diaphragm and ultra-small graded-index （GRIN） fiber optic lens， and a performance test method of the MEMS fiber optic acoustic sensor based on the swept-source optical coherence tomography （SS-OCT） demodulation system is investigated. The fabrication process of the MEMS optical fiber acoustic sensor combining the MEMS diaphragm and ultra-small GRIN optical fiber lens is designed and studied on the basis of modeling and analysis， and an acoustic and vibration measurement system based on SS-OCT is constructed. The performance test and calibration of the sensor are performed by conducting measurement experiments of a single-frequency acoustic signal， a mixed-frequency acoustic signal， frequency response， sound pressure sensitivity， and system stability. The results show that the frequency response range of the studied MEMS fiber optic acoustic sensor sample is 50 Hz-4.5 kHz. At a frequency of 300 Hz， the sound pressure sensitivity of the sensor is 21.63 nm/Pa， signal-to-noise ratio is 44.1 dB， linearity is 98.97%， and repeatability standard deviation is 0.003. The studied MEMS optical fiber acoustic sensor is shown to be feasible， and its sensing performance can be effectively measured by using the SS-OCT demodulation system..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1406 (2022)
Crosstalk correction of array fibers applied to beam quality measurement
Jie LUO, Laian QIN, Zaihong HOU, Wenyue ZHU, and Silong ZHANG
To reduce the error in a beam quality measurement system， which is caused by the output crosstalk of array fibers， a correction method combining hardware design and algorithm construction is proposed， and related principal research and method verification are conducted. First， the crosstalk effect of the array fibers iTo reduce the error in a beam quality measurement system， which is caused by the output crosstalk of array fibers， a correction method combining hardware design and algorithm construction is proposed， and related principal research and method verification are conducted. First， the crosstalk effect of the array fibers is analyzed based on beam quality measurement requirements and the fiber transmission principle. Second， the principle of crosstalk correction is verified by combining the Lambertian scattering principle and experimental results： the Lambertian scattering principle is used to reduce the divergence angle difference of the output light of fibers， establishing a unified diffuse model to correct spot crosstalk， and the deconvolution algorithm is then used to restore the target spot. Third， the principle of a targeted deconvolution algorithm is introduced， and the design of the relevant algorithm parameters is discussed. Finally， a comparison and analysis of the real spot， the uncorrected spot， and the corrected spot output produced by the fiber are conducted， and the experiment is found to verify the feasibility and effectiveness of the correction method. The experimental results reveal that compared to the uncorrected spot， the relative root mean square error of the intensity distribution of the corrected spot is reduced from 36.06% to 4.67%， and the relative root mean square error of the power in the bucket is reduced from 7.79% to 0.73%. The relative error of the beam width where the power in the bucket is 86.5% is reduced from 10.83% to 3.46%. The total time of image processing and parameter calculation using correction algorithm is about 8 s..
Optics and Precision Engineering
- Publication Date: Jun. 25, 2022
- Vol. 30, Issue 12, 1418 (2022)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20