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Evaluation of occlusion immunities of free-space orbital angular momentum shift keying

Optics Express 2025年第6期33卷 13494-13505页

作者： Yang, Jinyu Zhang, Shurui Li, Lang Gao, Mingwei Gao, Chunqing Fu, Shiyao School of Optics and Photonics Beijing Institute of Technology Beijing100081 China Key Laboratory of Information Photonics Technology Ministry of Industry and Information Technology of the People’s Republic of China Beijing100081 China Key Laboratory of Photoelectronic Imaging Technology and System Ministry of Education of the People’s Republic of China Beijing100081 China National Key Laboratory on Near-Surface Detection Beijing100072 China

Orbital angular momentum (OAM) provides a new high-dimensional degree-of-freedom for lasers enabling high-dimensional shift keying, thus showing huge potential in free-space optical data-transmissions. Ensuring the accuracy of data transmission is of concern in any communication system. However, in the free-space OAM shift keying link, interferences from environmental occlusions will broaden the OAM spectrum and thus affect the correctness of information received. In this paper, the occlusion immunities of two commonly used OAM shift keying strategies—OAM-encoding-symbols and OAM-encoding-bits—are evaluated under different occlusion scenarios. We introduce radial, azimuthal, and random occlusions into the link and then analyze the bit error rate (BER) of various OAM shift keying strategies. The results illustrate that the strategy of OAM-encoding-symbols exhibits stronger occlusion immunity with zero BER than OAM-encoding-bits. Moreover, proof-of-concept experiments are done to transmit grayscale images under occlusions. The final decoding results show identical data-transmission performance with simulations. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Bit error rate

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Selective formation of generalized optical skyrmions

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Optics Letters 2025年第9期50卷 2840-2843页

作者： Zhang, Haojun Gao, Chunqing Fu, Shiyao School of Optics and Photonics Beijing Institute of Technology Beijing100081 China Key Laboratory of Information Photonics Technology Ministry of Industry and Information Technology of the People’s Republic of China Beijing100081 China Key Laboratory of Photoelectronic Imaging Technology and System Ministry of Education of the People’s Republic of China Beijing100081 China National Key Laboratory on Near-Surface Detection Beijing100072 China

Optical skyrmions, a type of topologically protected quasiparticle, have undergone various deformations in recent years. In this Letter, we present a scheme that can achieve the selective formation of generalized optical skyrmions. In our proposal, a liquid-crystal spatial light modulator and a variable liquid-crystal retarder, both of which are commonly programmable devices, are employed, allowing for the on-demand precise manipulation of topological textures of various quasiparticles including but not limited to skyrmions, antiskyrmions, and bimerons. The proof-of-concept experiments illustrate that generalized optical skyrmions whose skyrmion number up to 5 can be well generated with on-demand tailored topological textures. While maintaining a simple setup, the system demonstrates a notable capacity for the manipulation of intricate high-order textures, signifying its considerable potential for extensive and sophisticated applications in the generation and manipulation of skyrmions. © 2025 Optica Publishing Group.

关键词： Topology

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Unmanned unexploded ordnance detection system based on magnetic method 20

Unmanned unexploded ordnance detection system based on magne...

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20th International Conference on Ground Penetrating Radar, GPR, 2024

作者： Xu, Y.L. Zhou, Y.J. Ding, K. Lv, R.Q. Wu, M.W. Wang, Z. Science and Technology on Near-Surface Detection Laboratory Wuxi214035 China The 50th Research Institute of China Electronics Technology Group Corporation Shanghai200331 China

Magnetic method is one of the main methods of UXO detection. This paper uses cesium optical pump magnetic detection module combined with UAV to build an unmanned UXO detection system, and introduces the detection principle and composition of the system. At the same time, the system is used to detect four kinds of UXO targets. The test results show that the system can detect ferromagnetic UXO targets, and can locate the position of UXO targets through magnetic anomaly images. Finally, the limit detection range of four kinds of targets is tested, and the limit detection range of 155 projectiles can reach 4.5m, which meets the actual detection requirements © Published under licence by IOP Publishing Ltd.

关键词： Target tracking

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Semi-supervised Medical Image Segmentation based on Coarse-Fine Dual Training Streams

Semi-supervised Medical Image Segmentation based on Coarse-F...

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2024 IEEE International Conference on Bioinformatics and Biomedicine, BIBM 2024

作者： Sun, Lizhi Huang, Yong Qiao, Zhengyu Yang, Boyu Li, Xiaochen Hao, Qun Beijing Institute of Technology School of Optics and Photonics Beijing China Yangtze Delta Region Academy Beijing Institute of Technology National Key Laboratory on Near Surface Detection Jiaxing China

ISBN: (纸本)9798350386226

Commonly used semi-supervised medical segmentation networks usually use consistent learning under different data perturbations to regularise training, ignoring the multiscale information of the data itself. Therefore, this paper proposes a new network based on coarse and fine dual training streams(CF-UNet), which consists of a backbone network and auxiliary learning branches(ALB). Our approach has the following two novel designs: 1) We design a simple and effective coarse- fine dual training streams. Specifically, in the coarse training stream, we improve the robustness and generalisation of the model by establishing regularisation between different strong and weak perturbation views. In the fine training stream, we introduce an auxiliary learning branch to improve the prediction performance of the backbone network.2) In the ALB module, we design the channel spatial fusion attention module (CSMA) and multiscale large kernel convolutional attention (MS-LKA) to perform feature extraction and fusion from a variety of scales. We evaluate our proposed method on ACDC and DRIVE datasets and numerous experiments have shown that our CF-UNet outperforms state-of-the-art networks. Code is available at https://***/slz-bit/CF-UNet. © 2024 IEEE.

关键词： Image segmentation

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A Rail Obstacle Target detection technology Based on the Perspective of Unmanned Aerial Vehicle 3rd

A Rail Obstacle Target Detection Technology Based on the Per...

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3rd International Conference on Advanced Intelligent Technologies, ICAIT 2022

作者： Du, Xing Yue Xu, Yue Lin Song, Guang Zhao Wang, Jian Jun CSSC Ocean Exploration Technology Institute Co. Ltd Wuxi China Science and Technology On Near-Surface Detection Laboratory Wuxi China

ISBN: (纸本)9789819952021

Based on the target detection results of the rail obstacles from the perspective of the UAV, it can assist in obstacle breaking and landing operations. At present, the rail obstacle target technology from the perspective of UAV has difficulties such as small target areas and dense targets. This paper adopts the YOLO5 base model structure, and then adopts transfer learning, transformer self-attention mechanism, CBAM attention module, and multi-scale hole convolution to optimize the model structure. The final model can be run on small devices such as drones with good accuracy results. The experimental results show that the final index AP@0.5 is 0.89, AP@0.5:0.95 is 0.68, which verifies the effectiveness of the proposed technology. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Unmanned aerial vehicles (UAV)

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Design and Verification of a Dielectric Laser Accelerator Test System for Sub-Relativistic Electrons 10

Design and Verification of a Dielectric Laser Accelerator Te...

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Nano-optoelectronics and Micro/Nano-photonics X 2024

作者： Chen, Ke Li, Dandan Liu, Ziyang Yang, Chenyi Lu, Bingheng Yang, Yadong Wang, Qianqian School of Optics and Photonics Beijing Institute of Technology Beijing100081 China National Key Laboratory on Near-surface Detection Beijing10072 China Key Laboratory of Photonic Information Technology Ministry of Industry and Information Technology Beijing100081 China

ISBN: (纸本)9781510682160

Dielectric laser accelerators (DLAs) can achieve acceleration gradients that are 1 to 2 orders of magnitude higher than traditional radiofrequency (RF) accelerators. Due to the micrometer-scale dimensions of the DLA acceleration structure, on the one hand, high requirements are imposed on the quality of the electron beam and the alignment among the electron beam, driving laser, and DLA in experiments. On the other hand, although the DLA acceleration gradient is very high, the acceleration distance is insufficient, resulting in relatively small absolute energy gain for sub-relativistic electrons after DLA acceleration. These electrons are susceptible to interference from stray electromagnetic fields during propagation, posing significant challenges to the resolution and accuracy of sub-relativistic electron energy spectrum testing. Based on the principle of laser-driven grating-structure DLA for accelerating electron beams, this paper designs a complete test system, constructs electronic dynamics simulation models and magnetic field measurement electron energy spectrum simulation models for verification, designs a double-layer magnetic shunt to shield the interference of leakage magnetic fields on electrons in the simulation, considers factors such as the beam spot radius, divergence angle, and geomagnetic field intensity of the electron beam that conform to experimental conditions, and finally obtains simulated images of electron spots on the fluorescent screen after the electron beam is deflected by the magnetic field. The electron dynamics simulation results show that the electron beam achieves a maximum energy gain of 14.4401 keV over an acceleration length of 36 μm, with an acceleration gradient reaching 401.114 MeV/m. Based on the acceleration effect, a magnetic field of BB = 170 Gs is set, and an electron spot after deflection is obtained. The edges of the spots before and after acceleration are separated by Δd = 4.2889 mm, and the maximum energy gain measurem

关键词： Fluorescent screens

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Temporal multiplexing coding strategy for spatiotemporal compressed imaging 4

Temporal multiplexing coding strategy for spatiotemporal com...

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4th International Computational Imaging Conference, CITA 2024

作者： Hao, Xiaowen Ke, Jun School of Optics and Photonics Beijing Institute of Technology Beijing100081 China Key Laboratory of Photo-electronic Imaging Technology and System Ministry of Education of China Beijing100081 China National Key Laboratory on Near-surface Detection Beijing100072 China

ISBN: (纸本)9781510688834

Spatiotemporal compressed imaging(STCI) aims to improve the spatial and temporal resolution of an imaging system simultaneously, which can effectively alleviate the mutual constraints between the two imaging resolutions. However, the development of STCI is limited by the effectively modulate target scenes in dual-domain, and by the back-end reconstruction process which doesn't work well for high compression ratio(CR). In this paper, we propose a temporal multiplexing coding strategy for STCI, which can effectively help the reconstruction algorithm for a large CR. Simulated experiments are implemented to demonstrate our idea. The proposed method can achieve nice spatiotemporal reconstructions with CR equal to 128:1, in which the spatial CR is 16:1 and the temporal CR is 8:1. © 2025 SPIE.

关键词： Image coding

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Optimizing object classification with single-pixel imaging and transformer networks 4

Optimizing object classification with single-pixel imaging a...

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4th International Computational Imaging Conference, CITA 2024

作者： Cheng, Yin Liao, Yusen Sun, Xin Ke, Jun School of Optics and Photonics Beijing Institute of Technology Beijing100081 China Key Laboratory of Photo-electronic Imaging Technology and System Ministry of Education of China Beijing100081 China National Key Laboratory on Near-surface Detection Beijing100072 China

ISBN: (纸本)9781510688834

Traditional computer vision tasks rely on high-quality images for classification, but single-pixel imaging (SPI) uses compressive sensing with a bucket detector to simplify hardware and reduce costs. However, factors like atmospheric turbulence can degrade SPI image quality, lowering classification accuracy. To address this, a block-based single-pixel image-free transformer classification framework is proposed. It uses a learnable binary sampling matrix for flexible sampling during SPI and divides the measurements into blocks, which are processed by a transformer network. Each block is treated as a sequence element, allowing the transformer to capture spatial and contextual relationships. Experiments show strong robustness to atmospheric turbulence, achieving 87% classification accuracy even at a 1% sampling rate, making this method suitable for challenging environments. © 2025 SPIE.

关键词： Pixels

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Improved IMM algorithm based on support vector regression for UAV tracking

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Journal of Systems Engineering and Electronics 2022年第4期33卷 867-876页

作者： ZENG Yuan LU Wenbin YU Bo TAO Shifei ZHOU Haosu CHEN Yu Shanghai Spaceflight Electronic and Communication Equipment Research Institute Shanghai 201109China Science and Technology on Near-Surface Detection Laboratory Wuxi 214035China School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNanjing 210094China

With the development of technology, the relevant performance of unmanned aerial vehicles(UAVs) has been greatly improved, and various highly maneuverable UAVs have been developed, which puts forward higher requirements on target tracking technology. Strong maneuvering refers to relatively instantaneous and dramatic changes in target acceleration or movement patterns, as well as continuous changes in speed,angle, and acceleration. However, the traditional UAV tracking algorithm model has poor adaptability and large amount of calculation. This paper applies support vector regression(SVR)to the interacting multiple model(IMM) algorithm. The simulation results show that the improved algorithm has higher tracking accuracy for highly maneuverable targets than the original algorithm, and can adjust parameters adaptively, making it more adaptable.

关键词： interacting multiple model(IMM)filter constant acceleration(CA) unmanned aerial vehicle(UAV) support vector regression(SVR)

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Passive detection Beamforming Based on Arc Array 3rd

Passive Detection Beamforming Based on Arc Array

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3rd International Conference on Advanced Intelligent Technologies, ICAIT 2022

作者： Li, MengLei Xu, YueLin Wang, ShiRui Li, YiQing CSSC Ocean Exploration Technology Institude Co. Ltd Jiangsu Wuxi China Science and Technology On Near-Surface Detection Laboratory Jiangsu Wuxi China

ISBN: (纸本)9789819952021

Linear arrays are widely used in underwater acoustic detection equipment, but they often have the problem of port and starboard ambiguity, and the azimuth resolution will decrease rapidly with the increase of the deviation from the natural pointing angle. In order to solve this problem, the conventional beamforming method is adopted in this paper, and the beamforming performance of non-linear arrays is simulated and studied. The simulation results show that the ring array can have consistent beam response and azimuth resolution in any direction. Further considering that the actual application scenario of the array is the shore, the actual required detection range is from −90° to 90°. In order to avoid the waste of array elements, the beamforming performance of the arc array is studied. The simulation results show that for a semi-circular arc array with a beam radius product of 21π, the azimuth resolution can be maintained between 2° and 4° in the range of −70° to 70°, which is beneficial to the azimuth estimation of small targets and meets the requirements of usage requirements. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Beamforming

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