Journals >Opto-Electronic Engineering
Contents
2023
Volume: 50 Issue 7
9 Article(s)
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Research Articles
Study of off-axis telescope misalignment correction method using out-of-focus spot
Siheng Tian, Yongmei Huang, Yangjie Xu, Xinyuan Nan, Qiongyan Wu, Chunsheng Xiang, and Wei Tang
Off-axis reflector telescopes are mainly used in space astronomy observation and other related fields. The image quality of off-axis two-inversion telescopes is sensitive to lens misalignment and is more difficult to calibrate using a laser interferometer after misalignment in an operating environment. To address this Off-axis reflector telescopes are mainly used in space astronomy observation and other related fields. The image quality of off-axis two-inversion telescopes is sensitive to lens misalignment and is more difficult to calibrate using a laser interferometer after misalignment in an operating environment. To address this challenge, this paper proposes a method that uses the out-of-focus spot map of the system for infinity point targets and uses the Swin-Transformer network to calculate the amount of lateral misalignment of the secondary mirror. Theoretical calculations were used to determine the camera defocus positions that could avoid the multi-solution problem, and simulations were used to investigate the effect of different defocus amounts on calibration accuracy. The trained network uses a frame of out-of-focus spot map of the out-of-tune system to perform the estimation of the amount of out-of-tune. Both simulation analysis and experimental results verify the effectiveness of the method, which can achieve high accuracy and fast correction of out-of-tune telescope systems in the working environment..
Opto-Electronic Engineering
- Publication Date: Aug. 20, 2023
- Vol. 50, Issue 7, 230040 (2023)
Progressive multi-granularity ResNet vehicle recognition network
Shengjun Xu, Yang Jing, Haitao Li, Zhongxing Duan, Fuyou Liu, and Minghai Li
Aiming at the problem that vehicle models are difficult to recognize due to differences in vehicle posture and viewing angles, a vehicle model recognition network based on progressive multi-granularity ResNet is proposed. Firstly, a progressive multi-granularity local convolution module is proposed by using the ResNet Aiming at the problem that vehicle models are difficult to recognize due to differences in vehicle posture and viewing angles, a vehicle model recognition network based on progressive multi-granularity ResNet is proposed. Firstly, a progressive multi-granularity local convolution module is proposed by using the ResNet network as the backbone network to perform local convolution operations on vehicle images of different granularity levels, so that local features of vehicles at different granularity levels can be paid attention to when the network is reconstructed. Secondly, for the multi-granularity local feature map, the random channel discarding module is adopted to perform random channel discarding, which suppresses the network's attention to the vehicle's salient regional features and improves the attention of non-salient features. Finally, a progressive multi-granularity training module is proposed. A classification loss is added in each training step to guide the network to extract more discriminative and diverse vehicle multi-scale features. Experimental results show that the recognition accuracy of the proposed network reaches 95.7%, 98.8%, and 97.4% respectively on the Stanford-cars dataset, the Compcars network dataset, and the vehicle model dataset VMRURS in real scenes. In comparison with the comparative network, the proposed network not only has higher recognition accuracy but also has better robustness..
Opto-Electronic Engineering
- Publication Date: Aug. 20, 2023
- Vol. 50, Issue 7, 230052 (2023)
Axial attention-guided anchor classification lane detection
Xin Luo, Yingping Huang, and Zhenming Liang
Lane detection is a challenging task due to the diversity of lane lines and the complexity of traffic scenes. The detection results of the existing detection methods are not ideal when the vehicle is driving in congestion, at night, and the lane lines are not clear or blocked on the road such as curves. Based on the frLane detection is a challenging task due to the diversity of lane lines and the complexity of traffic scenes. The detection results of the existing detection methods are not ideal when the vehicle is driving in congestion, at night, and the lane lines are not clear or blocked on the road such as curves. Based on the framework of detection methods, a method that axial attention-guided anchor classification lane detection is proposed to solve two problems. The first is the problem of missing visual cues when lane lines are unclear or missing. The second problem is the lack of feature information caused by using sparse coordinates on mixed anchors, which leads to a decline of detection accuracy. Therefore, an axial attention layer is added to the backbone network to focus on prominent features of the row and column directions to improve the accuracy. Extensive experiments are conducted on the TuSimple and CULane datasets. Experimental results show that the proposed method is robust under various conditions while showing comprehensive advantages in terms of detection accuracy and speed compared with existing advanced methods..
Opto-Electronic Engineering
- Publication Date: Aug. 20, 2023
- Vol. 50, Issue 7, 230079 (2023)
Inverse-designed silicon-based on-chip power splitters
Hansi Ma, Te Du, Xinpeng Jiang, and Junbo Yang
The silicon-based on-chip power splitter, an important component of the photonic integrated circuits, has much wider scope of applications such as feedback circuits, tap-port power monitoring, and optical quantization. The design methods of the nanophotonic devices can be roughly divided into the forward design and invThe silicon-based on-chip power splitter, an important component of the photonic integrated circuits, has much wider scope of applications such as feedback circuits, tap-port power monitoring, and optical quantization. The design methods of the nanophotonic devices can be roughly divided into the forward design and inverse design methods. This review article outlines the differences and connections between the forward design and inverse design methods, and classifies the inverse design algorithms. In addition, the review article summarizes the representative inverse-designed silicon-based on-chip power splitters in recent years, including multichannel power splitters, arbitrary-split-ratio power splitters, multimode power splitters, broadband power splitters, and multifunction power splitters. Finally, the summary and outlook are made on the development trend of the inverse design algorithms and the inverse-designed power splitters..
Opto-Electronic Engineering
- Publication Date: Aug. 20, 2023
- Vol. 50, Issue 7, 230086 (2023)
Effect of polarized laser illumination on imaging contrast of multilayer thin film structure
Zijian Zhang, Tianyi Wang, Xin Xu, Jixiang Wang, Xin Zhang, Ruobing Zhang, Guohua Shi, and Hong Ye
Optical multilayer interference tomography (OMLIT) is used in correlated light and electron microscopy to image a large field through an optical microscope, providing the navigation of the region of interest for later nanometer-resolution electron microscope imaging. In order to further improve the imaging contrast andOptical multilayer interference tomography (OMLIT) is used in correlated light and electron microscopy to image a large field through an optical microscope, providing the navigation of the region of interest for later nanometer-resolution electron microscope imaging. In order to further improve the imaging contrast and positioning accuracy of thin film samples, a theoretical model combining polarization illumination and OMLIT is proposed. This model is written in the matrix formalism and the propagation of polarized light through different layers with various incident angles is simulated. The simulation results show that using the polarized light with an electric field oscillating parallel to the incidence plane (p-polarization) exhibits a much higher imaging contrast than the unpolarized light. Especially when the p-polarized light illuminates on an OMLIT sample, of which the first coating layer is Ag, with an incidence angle of 62°, the imaging contrast can be vastly enhanced by 138 times. The presented model provides a theoretical basis for polarization illumination OMLIT, pathing a new technical way for the development of the correlated light and electron microscopy technique..
Opto-Electronic Engineering
- Publication Date: Aug. 20, 2023
- Vol. 50, Issue 7, 230089 (2023)
Femtosecond laser printing of vanadium dioxide based optical meta-structures with tunable spectra engineering
Jiaqi Zhu, Shiyu Wu, Shichao Song, and Yaoyu Cao
Over the past few years, the field of micro-/nano- photonics has witnessed a surge in research focused on developing innovative optical devices that offer dynamic spectra engineering. Among the materials showing promise in this area, vanadium dioxide (VO2) can actively manipulate its refractive index via a phase transiOver the past few years, the field of micro-/nano- photonics has witnessed a surge in research focused on developing innovative optical devices that offer dynamic spectra engineering. Among the materials showing promise in this area, vanadium dioxide (VO2) can actively manipulate its refractive index via a phase transition process, enabling the dynamic manipulation of spectra. In this work, a photosensitive polymer nanocomposite with tunable effective refractive index is prepared by incorporating VO2 nanocrystals into methacrylate monomers, which takes advantages of the phase change characteristics of VO2 and the photopolymerization properties of the monomer. In addition, with the aid of the state-of-the-art femtosecond laser processing technology, highly precise two-dimensional and three-dimensional micro-/nano- optical structures embedded with the phase change capabilities outlined by VO2 are achieved. Fascinatingly, the spectra measurements via Fourier transform infrared spectrometer reveal that when subjected to the critical phase transition temperatures, the printed micro-/nano- structures will undergo a thermally induced phase transition of the VO2 nanocrystals embedded within them. Consequently, there is a discernible alteration in the effective refractive index of the optically functionalized structure, inspiring the dynamic manipulation of the short-band spectra..
Opto-Electronic Engineering
- Publication Date: Aug. 20, 2023
- Vol. 50, Issue 7, 230095 (2023)
2.8 μm passively Q-switched mode-locked fiber laser using TiCN as saturable absorber
Shanshan Ye, Haibo Huang, Songyuan Chen, Junzhe Tao, Yuxuan Wen, and Weiqing Gao
A 2.8 μm passively Q-switched mode-locked erbium-doped fluoride fiber laser based on material saturable absorption is reported in this paper. By depositing TiCN particles directly onto the cavity mirror as the saturable absorber and using the vertical cleaved end of the fluoride fiber as an output coupler, the 2.8 μm pA 2.8 μm passively Q-switched mode-locked erbium-doped fluoride fiber laser based on material saturable absorption is reported in this paper. By depositing TiCN particles directly onto the cavity mirror as the saturable absorber and using the vertical cleaved end of the fluoride fiber as an output coupler, the 2.8 μm pulsed fiber lasing with a low laser threshold and a compact cavity structure is realized. When the pump power reaches 330 mW, the Q-switched mode-locked pulses begin to appear. With the increase of pump power, the repetition frequency of Q-switched pulse envelope increases from 14.34 to 32.57 kHz, and the pulse width decreases from 10.51 to 5.40 μs. Under the pump power of 650 mW, the maximum average output power of 25.83 mW is obtained, and the slope efficiency is about 7.2%..
Opto-Electronic Engineering
- Publication Date: Aug. 20, 2023
- Vol. 50, Issue 7, 230107 (2023)
Design of alignment subsystem for laser wireless power transmission system
Jinsong Kang, Yanping Zhou, Liangrong Sun, Fanwei Kong, and Yanting Lv
Laser alignment is a prerequisite for stable energy acquisition at the receiver end in laser wireless power transmission systems. Laser power transfer imposes high requirements on alignment accuracy, stability, and real-time performance. Therefore, a laser alignment system design method is proposed, and optimizations aLaser alignment is a prerequisite for stable energy acquisition at the receiver end in laser wireless power transmission systems. Laser power transfer imposes high requirements on alignment accuracy, stability, and real-time performance. Therefore, a laser alignment system design method is proposed, and optimizations are made to the region of interest extraction and image preprocessing methods. On one hand, the SSD (single shot multi-Box detector) model is improved by introducing MobileNet, incorporating spatial attention mechanism, and fusing semantics. The improved model is used for training and predicting the regions of interest. Compared to the original model, the training speed is improved by 71.67%, the model size is reduced by 52.48%, the real-time detection speed is increased by 295.30%, and the detection error is significantly reduced. On the other hand, the weights of grayscale conversion are optimized, and an adaptive threshold selection using a histogram is implemented. The elliptical fitting method and centroid method are employed to detect the spot and beacon center, reducing the error in spot localization. Experimental results show that the improved laser alignment system achieves a stable accuracy of over 95% and meets the requirements of accuracy, speed, and stability in application..
Opto-Electronic Engineering
- Publication Date: Aug. 20, 2023
- Vol. 50, Issue 7, 230109 (2023)
Infrared-visible person re-identification based on multi feature aggregation
Haijun Zheng, Bin Ge, Chenxing Xia, and Cheng Wu
Infrared-visible person re-identification has been widely used in video surveillance, intelligent transportation, security, and other fields. However, due to the differences between different image modalities, it brings great challenges to this field. The existing methods mainly focus on mitigating the differences betwInfrared-visible person re-identification has been widely used in video surveillance, intelligent transportation, security, and other fields. However, due to the differences between different image modalities, it brings great challenges to this field. The existing methods mainly focus on mitigating the differences between modes to obtain more discriminating features, but ignore the relationship between adjacent features and the influence of multi-scale information on global features. Here, a infrared-visible person re-identification method (MFANet) based on multi-feature aggregation is proposed to solve the shortcomings of existing methods. Firstly, the adjacent level features are fused in the feature extraction stage, and the integration of low-level feature information is guided to strengthen the high-level features and make the features more robust. Then, the multi-scale features of different receptive fields of view are aggregated to obtain rich contextual information. Finally, multi-scale features are used as a guide to strengthen the features to obtain more discriminating features. Experimental results on SYSU-MM01 and RegDB datasets show the effectiveness of the proposed method, and the average accuracy of SYSU-MM01 dataset reaches 71.77% in the most difficult all-search single-shot mode..
Opto-Electronic Engineering
- Publication Date: Aug. 20, 2023
- Vol. 50, Issue 7, 230136 (2023)
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