2024

• Record 397 of
  
  Title:A Cross-Level Interaction Network Based on Scale-Aware Augmentation for Camouflaged Object Detection
  
  Author(s):Ma, Ming(1); Sun, Bangyong(1,2)
  Source: IEEE Transactions on Emerging Topics in Computational Intelligence  Volume: 8  Issue: 1  DOI: 10.1109/TETCI.2023.3299305  Published: February 1, 2024  
  Abstract:Camouflaged object detection (COD), with the task of separating the camouflaged object from its color/texture similar background, has been widely used in the fields of medical diagnosis and military reconnaissance. However, the COD task is still a challenging problem due to two main difficulties: large scale-variation for different camouflaged objects, and extreme similarity between the camouflaged object and its background. To address these problems, a cross-level interaction network based on scale-aware augmentation (CINet) for the COD task is proposed. Specifically, a scale-aware augmentation module (SAM) is firstly designed to perceive the scales information of the camouflaged object by calculating an optimal receptive field. Furthermore, a cross-level interaction module (CLIM) is proposed to facilitate the interaction of scale information at all levels, and the context of the feature maps is enriched accordingly. Finally, with the purpose of fully utilizing these features, we design a dual-branch feature decoder (DFD) to strengthen the connection between the predictions at each level. Extensive experiments performed on four COD datasets, e.g., CHAMELEON, CAMO, COD10K, and NC4K, demonstrate the superiority of the proposed CINet compared with 21 existing state-of-the-art methods. © 2017 IEEE.
  Accession Number: 20233414601306
• Record 398 of
  
  Title:High-Precision Domain Adaptive Detection Method for Noncooperative Spacecraft Based on Optical Sensor Data
  
  Author(s):Zhang, Gaopeng(1); Zhang, Zhe(1); Lai, Jiahang(2); Zhang, Guangdong(1); Ye, Hao(1); Yang, Hongtao(1); Cao, Jianzhong(1); Du, Hubing(3); Zhao, Zixin(4); Chen, Weining(1); Lu, Rong(1); Wang, Changqing(2)
  Source: IEEE Sensors Journal  Volume: 24  Issue: 8  DOI: 10.1109/JSEN.2024.3370309  Published: April 15, 2024  
  Abstract:The accurate detection of noncooperative spacecraft based on optical sensor data is essential for critical space tasks, such as on-orbit servicing, rendezvous and docking, and debris removal. Traditional object detection methods struggle in the challenging space environment, which includes extreme variations in lighting, occlusions, and differences in image scale. To address this problem, this article proposes a high-precision, deep-learning-based, domain-adaptive detection method specifically tailored for noncooperative spacecraft. The proposed algorithm focuses on two key elements: dataset creation and network structure design. First, we develop a spacecraft image generation algorithm using cycle generative adversarial network (CycleGAN), facilitating seamless conversion between synthetic and real spacecraft images to bridge domain differences. Second, we combine a domain-adversarial neural network with YOLOv5 to create a robust detection model based on multiscale domain adaptation. This approach enhances the YOLOv5 network's ability to learn domain-invariant features from both synthetic and real spacecraft images. The effectiveness of our high-precision domain-adaptive detection method is verified through extensive experimentation. This method enables several novel and significant space applications, such as space rendezvous and docking and on-orbit servicing. © 2001-2012 IEEE.
  Accession Number: 20241115731816
• Record 399 of
  
  Title:Enhancing Aircraft Object Detection in Complex Airport Scenes Using Deep Transfer Learning
  
  Author(s):Zhong, Dan(1); Li, Tiehu(2); Li, Cheng(3)
  Source: Guangzi Xuebao/Acta Photonica Sinica  Volume: 53  Issue: 4  DOI: 10.3788/gzxb20245304.0415002  Published: April 2024  
  Abstract:Within the civil aviation airports of China，intricate traffic scenarios and a substantial flow of traffic are pervasive. Conventional monitoring methodologies，including tower observations and scene reports，manifest vulnerability to potential errors and omissions. Aircraft object detection at airport scenes remains a challenging task in the field of computer vision，particularly in complex environmental conditions. The issues of severe aircraft object occlusion， the dynamic nature of airport environments and the variability in object sizes pose difficulties for accurate object detection tasks. In response to these challenges，we propose an enhanced deep learning model for aircraft object detection at airport scenes. Given the practical constraints of limited hardware computational power at civil aviation airports，the proposed method adopts the ResNet-50 model as the foundational backbone network. After pre-training on publicly available datasets，transfer learning techniques are employed for fine-tuning within the specific target domain of airport scenes. Deep transfer learning methods are utilized to enhance the feature extraction capabilities of the model，ensuring better adaptation to the limited aircraft dataset in airport scenarios. Additionally，we incorporate an adjustment module，consisting of two convolution layers，into the backbone network with a residual structure. The adjustment module can increase the receptive field of deep feature maps and improve the model's robustness. Moreover，the proposed method introduces the Feature Pyramid Network，establishing lateral connections across various stages of ResNet-50 and top-down connections. FPN generates and extracts feature information from multiple scales，facilitating the fusion of features in the feature maps. This enhances the accuracy of multi-scale target detection in the task of object detection. Furthermore，optimizations have been implemented on the detection head，composed of parallel classification and regression branches. This detection head aims to strike a balance between the accuracy and real-time performance of target detection，facilitating the fast and accurate generation of bounding boxes and classification outcomes in the model's output. The loss function incorporates weighted target classification loss and localization loss，with GIoU loss used to calculate the localization loss. Moreover， we construct a comprehensive airport scene dataset named Aeroplane， to evaluate the effectiveness of our proposed model. This dataset encompasses real images of diverse aircraft in various backgrounds and scenes，including challenging weather conditions such as rain，fog，and dust，as well as different times of day like noon，dusk，and night. Most of the color images are captured from the camera equipment deployed in various locations，including terminal buildings，control towers，ground sentry posts and other places of a civil aviation airport surveillance system in China. The diversity of the dataset contributes to enhancing the generalization performance of the model. The Aeroplane dataset is structured adhering to standards and is scalable for future expansion. And we conduct experiments on the Aeroplane dataset. Experimental results demonstrate that our proposed model outperforms classic approaches such as RetinaNet，Inception-V3+FPN，and ResNet-34+FPN. Compared to the baseline method，ResNet-50+FPN， our model achieves a 4.9% improvement in average precision for single-target aircraft detection，a 4.0% improvement for overlapped aircraft detection，and a 4.4% improvement for small target aircraft detection on the Aeroplane dataset. The overall average precision is improved by 2.2%. Through experimental validation，our proposed model has demonstrated significant performance improvement in aircraft target detection within airport scenarios. The presented model exhibits robust scene adaptability in various airport environments，including non-occlusion，occlusion，and complex scenes such as nighttime and foggy weather. This validates its practicality in real-world airport settings. The balanced design of real-time performance and accuracy in our approach renders it feasible for practical applications，providing a reliable aircraft target detection solution for airport surveillance systems and offering valuable insights for the task of object detection. © 2024 Chinese Optical Society. All rights reserved.
  Accession Number: 20241715960809
• Record 400 of
  
  Title:Experimental study on the implementation method of short pulse laser in distance-selective imaging system
  
  Author(s):Wang, Chong(1); Li, Miaomiao(1); Yang, Jiahao(1); Zhu, Bingli(2); Han, Jianghao(1); Dang, Wenbin(1)
  Source: Optics and Laser Technology  Volume: 171  Issue:   DOI: 10.1016/j.optlastec.2023.110358  Published: April 2024  
  Abstract:Conventional distance-selective imaging systems use lasers that are large in size, high in power consumption, and high in cost. In order to reduce the system size and reduce the system power consumption and cost, The principles and design methods of two drive circuits for generating narrow pulse lasers based on step recovery diodes SRD (combined with shorted transmission lines) and RF bipolar transistors are discussed, physically fabricated and tested, and the characteristics of the two pulse generators and the factors affecting the pulse width amplitude are analyzed. The experimental results show that the SRD-based method can generate a narrow pulse with a rise time of 456.8 ps, a fall time of 458.3 ps, a pulse width of 1.5 ns, and an amplitude of 2.38 V; the transistor-based method can generate a narrow pulse with a rise time of 903.5 ps, a fall time of 946.1 ps, a pulse width of 824 ps, and an amplitude of 2.46 V, both of which can reach a repetition frequency of 50 MHz. Both design methods can be combined with an external laser diode to achieve excellent short pulse laser output. © 2023
  Accession Number: 20234815126167
• Record 401 of
  
  Title:Auto-Alignment Non-Contact Optical Measurement Method for Quantifying Wobble Error of a Theodolite on a Vehicle-Mounted Platform
  
  Author(s):Li, Xiangyu(1,2,3); Hao, Wei(1,3); Xie, Meilin(1,3); Liu, Bo(1,3); Jiang, Bo(1,3); Lv, Tao(1,2,3); Song, Wei(1,2,3); Ruan, Ping(1,3)
  Source: Tehnicki Vjesnik  Volume: 31  Issue: 2  DOI: 10.17559/TV-20230510000617  Published: 2024  
  Abstract:During non-landing measurements of a theodolite, the accuracy of the goniometric readings can be compromised by wobble errors induced by various factors such as wind loads, theodolite driving torque, and the stiffness of the supporting structure. To achieve high-precision non-landing measurements, it is essential to accurately determine and correct the platform wobble errors affecting the azimuth and pitch pointing angles. In this paper, a non-contact optical measurement method is proposed for quantifying platform wobble errors. The method establishes an auto-alignment optical path between an autocollimator and a reflector in the measuring device. By detecting the deviation angle of the CCD image point as the optical path changes, precise measurements of the platform wobble errors can be obtained. Experimental results demonstrate that the measuring device can achieve an auto-alignment optical path within 5 minutes, significantly improving measurement efficiency. Furthermore, after measuring the platform wobble error and applying data correction, the average error in the azimuth pointing angle is reduced from 31.5″ to 9.8″, and the average error in the pitch pointing angle is reduced from 21″ to 9.2″. These results highlight the substantial correction effect achieved by the proposed method. © 2024, Strojarski Facultet. All rights reserved.
  Accession Number: 20241115717961
• Record 402 of
  
  Title:Constructing 1D/0D Sb2S3/Cd0.6Zn0.4S S-scheme heterojunction by vapor transport deposition and in-situ hydrothermal strategy towards photoelectrochemical water splitting
  
  Author(s):Liu, Dekang(1); Jin, Wei(1); Zhang, Liyuan(1); Li, Qiujie(1); Sun, Qian(1); Wang, Yishan(2); Hu, Xiaoyun(1); Miao, Hui(1)
  Source: Journal of Alloys and Compounds  Volume: 975  Issue:   DOI: 10.1016/j.jallcom.2023.172926  Published: February 25, 2024  
  Abstract:Antimony sulfide (Sb2S3) is widely used in photocatalysts and photovoltaic cells because of its abundant reserves, low toxicity, environmental friendliness, narrow band gap, and high light absorption capacity. Sb2S3 shows a quasi-one-dimensional structure composed of [Sb4S6]n nanoribbons, a lot of reported studies are focused on preparing Sb2S3 with [hk1] oriented dominant growth to improve the photogenerated carrier transport capacity of Sb2S3. However, there is relatively few research on the preparation of [hk1] oriented rod-like Sb2S3 by vapor transport deposition (VTD) method. In this work, the VTD method was used to prepare Sb2S3 with [hk1] oriented growth on the FTO substrate, and then composite with the ternary solid solution CdxZn1−xS. Finally, a novel Sb2S3/Cd0.6Zn0.4S S-scheme heterojunction with rod-like core-shell structure was successfully constructed, which could effectively improve the photoelectrochemical properties. Because the solid solution component x is adjustable, that is, CdxZn1−xS has continuously adjustable band gap width and energy level position, the Sb2S3/CdxZn1−xS heterojunction type can be regulated from Type-II to S-scheme. Photoelectrochemical (PEC) tests indicated that the composite photoanode Sb2S3/Cd0.6Zn0.4S achieved a higher photocurrent density (2.54 mA·cm−2, 1.23 V vs. RHE), which is about 4.31 times that of pure Sb2S3 nanorod photoanode (0.59 mA·cm−2, 1.23 V vs. RHE). © 2023 Elsevier B.V.
  Accession Number: 20234915144994
• Record 403 of
  
  Title:Three-dimensional crumpled d-Ti3C2Tx/PANI structure enabled by PANI interlayer spacing control for enhanced electrochemical performance
  
  Author(s):Zhao, Yuanbo(2); He, Weijun(2); Chen, Yanan(2); Liu, Yanan(2); Xing, Hongna(2); Zhu, Xiuhong(1,2); Feng, Juan(2); Liao, Chunyan(2); Zong, Yan(2); Li, Xinghua(2); Zheng, Xinliang(2)
  Source: Materials Today Communications  Volume: 39  Issue:   DOI: 10.1016/j.mtcomm.2024.108689  Published: June 2024  
  Abstract:The self-stacking and collapsing of few-layered Ti3C2Tx(d-Ti3C2Tx) results in its poor rate capability and cycle performance during charge/discharge processes. Constructing a three-dementional (3D) structure, introducing interlayer spacers and using alkaline electrolytes are effective and powerful strategies to resolve the problems. Herein, a 3D crumpled d-Ti3C2Tx/PANI composite was successfully prepared by HCl/LiF in-situ etching Ti3AlC2 to obtain d-Ti3C2Tx and polymerizing PANI onto its surface with ice-bath stirring. Benefiting from the synergistic effect of kinetically favorable structure, component and alkaline electrolytes, The PM-1 (d-Ti3C2Tx/PANI-1) as an electrode remarkably improves the electrochemical performances compared with the original d-Ti3C2Tx in 2 M KOH electrolyte. It exhibits a specific capacitance of 230 mF cm−2（115 F g−1）at 2 mA cm−2, high rate capability of 81.2% at 20 mA cm−2 and outstanding stability of 96.7% retention after 5000 cycles at 10 mA cm−2. Furthermore, an assembled symmetric supercapacitor (SSC) also presents an excellent stability performance with 82.4% retention after 5000 cycles at 8 mA cm−2 and a promising energy storage performance. The related work provides a good reference for the MXene-based electrode materials in the conditions of alkaline electrolytes. © 2024 Elsevier Ltd
  Accession Number: 20241315799736
• Record 404 of
  
  Title:Application of fine spectral detection and quantitative analysis technology in water quality and environmental monitoring of the Yangtze River main stream
  
  Author(s):Zhao, Yubo(1,2); Wang, Xueji(1); Liu, Xiao(1); Gong, Kaijie(3); Zou, Lei(4); Lin, Zhonghui(4); Yu, Tao(1); Yu, Weixing(1); Hu, Bingliang(1)
  Source: Dili Xuebao/Acta Geographica Sinica  Volume: 79  Issue: 1  DOI: 10.11821/dlxb202401004  Published: January 2024  
  Abstract:Water eco- environment monitoring is the premise and foundation of habitat protection. In view of the characteristics of the Yangtze River Basin's water system, which is diverse, complex, and ever- changing, higher requirements are put forward for monitoring methods. At present, the water quality monitoring methods for large surface water systems are still mainly based on manual sampling combined with laboratory chemical analysis or on-site hand-held instrumental analysis. There are problems such as method lag, single means, low frequency, and lack of non-point sources. Therefore, there is an urgent need for new system monitoring technology, which breaks through real-time, fast, non-point source quantitative and other practical needs, and provides a reliable data source for the comprehensive simulation of the Yangtze River water system. In this context, this paper proposes a fine spectral detection and quantitative analysis technology with completely independent intellectual property rights, and develops ground-based, space-based and other system technologies and equipment. With the support of the relevant projects, the demonstration application of systematic technology was carried out, and the space-ground stereoscopic monitoring was conducted in the key sections of the main stream of the Yangtze River, the Three Gorges Demonstration Area and the Poyang Lake Demonstration Area, and good results were achieved. The monitoring data are connected to the "Yangtze River Simulator" through the cloud platform, which provides fast real-time data support for its comprehensive operation, as well as a new method and application model for the comprehensive monitoring of large-scale water systems in the future. © 2024 Science Press. All rights reserved.
  Accession Number: 20240915663611
• Record 405 of
  
  Title:Influence of wavefront distortion on the measurement of pulse signal-to-noise ratio
  
  Author(s):Xing, Dingding(1,2); Yuan, Suochao(1); Kou, Jingwei(1); Da, Zhengshang(1)
  Source: Optics Communications  Volume: 554  Issue:   DOI: 10.1016/j.optcom.2023.130110  Published: March 1, 2024  
  Abstract:The high-fidelity measurement of the ultra-short and ultra-intense laser pulses' temporal signal-to-noise ratio (SNR) is of great significance. To the best of our knowledge, few studies have investigated the influence of wavefront distortion on the measurement of pulse SNR. In this work, a numerical model is constructed to study how wavefront distortion affects the measurement of ultra-short and ultra-intense pulse SNR by the single-shot third-order auto-correlation (TOAC) method. The nonlinear coupled-wave equations with wavefront distortion have been solved numerically by the split-step Fourier method and the fourth-order Runge-Kutta numerical algorithm. The wavefront distortion of the under-test fundamental wave will be transmitted to the second harmonic and third harmonic, leading to the phase mismatch in the second harmonic generation (SHG) and third harmonic generation (THG), further resulting in the deterioration of the measured SNR. We analyze the influence of different spatial frequencies and peak-to-valley (PV) values on the measurements of SNR. The larger the spatial frequency or PV value of the wavefront distortion, the more severe the degradation of the SNR. © 2023 Elsevier B.V.
  Accession Number: 20240215363991
• Record 406 of
  
  Title:On-orbit calibration of space camera lens distortion using a single image
  
  Author(s):Zhang, Gaopeng(1); Wang, Feng(1); Zhang, Guangdong(1,2); Zhang, Zhe(1); Du, Hubing(3); Zhao, Zixin(4); Wang, Changqing(2); Cao, Jianzhong(1); Zhao, Jingwei(3); Li, Yanjie(3); Lu, Rong(1)
  Source: Optics and Lasers in Engineering  Volume: 177  Issue:   DOI: 10.1016/j.optlaseng.2024.108140  Published: June 2024  
  Abstract:Since space cameras need to withstand the harsh mechanical and thermal conditions in the space environment for a long time, it is necessary to calibrate them in orbit. However, existing calibration methods have various disadvantages, making them impossible to use in orbit. To address this problem, we present an on-orbit calibration of space camera lens distortion with the vanishing points obtained from a single image of the solar panel. First, we propose a parallel-line-extraction method based on collinear constraints to obtain the parallel lines. Then, we train the optimal vanishing point using the common point constraint method. Using the optimal vanishing point, we establish the optimization function of lens distortion based on vanishing point consistency. Finally, we present an improved genetic algorithm to solve the optimization function. Simulations and experiments show that the proposed method is flexible and robust. © 2024 Elsevier Ltd
  Accession Number: 20241015672218
• Record 407 of
  
  Title:Accurate Real-Time Laser Spot Locating Based on Template Correlation in Intersatellite Laser Communications
  
  Author(s):Meng, Xiangsheng(1,2); Liu, Wen(1,2); Han, Junfeng(1,2); Tian, Yan(1,2); Liu, Jun(1,2); Ma, Caiwen(1,2)
  Source: IEEE Photonics Journal  Volume: 16  Issue: 1  DOI: 10.1109/JPHOT.2023.3335234  Published: February 1, 2024  
  Abstract:In intersatellite laser communications, the centroiding accuracy of a laser spot is crucial for maintaining steady communication links. However, the systematic error introduced by discrete sampling restricts further improvement of centroiding accuracy when choosing algorithms that are widely used in engineering. Additionally, the ultrahigh computational complexity and multiple-step iterations of the Gaussian fitting (GF) algorithm are unsuitable for real-time implementation, even though the algorithm can achieve the highest centroiding accuracy. In this study, we propose a laser spot centroiding algorithm based on template correlation to simultaneously satisfy the requirements of real-time performance and accuracy. The proposed algorithm evaluates the central location of a laser spot by obtaining the index of the maximum Pearson correlation coefficient (PCC). Simulations performed under different conditions reveal that the proposed algorithm is robust against the interference of background noise and the bad pixels. Moreover, experimental verification is performed based on the implementation on a Field-Programmable Gate Array (FPGA) in real-time, meanwhile its accuracy is on the same level as that of the GF algorithm and better than those of other widely-used algorithms. Therefore, the proposed algorithm is suitable for accurate real-time locating of laser spots in engineering applications of the intersatellite laser communications. © 2009-2012 IEEE.
  Accession Number: 20234915180528
• Record 408 of
  
  Title:Optimization of multilayer capacitive charge division anode for MCP imaging detectors
  
  Author(s):Yang, Kai(1,2); Bai, Yonglin(1); Wang, Bo(1); Cao, Weiwei(1); Zhu, Bingli(1); Bai, Xiaohong(1); Zheng, Jinkun(1); Zhang, Shengdan(1,2); Wang, Chao(1); Chen, Zhen(1); Yang, Yang(1)
  Source: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment  Volume: 1063  Issue:   DOI: 10.1016/j.nima.2024.169285  Published: June 2024  
  Abstract:A three-dimensional numerical model developed based on the finite element method to simulate the position-reconstruction performance of multilayer capacitive anodes is presented. The charge collection efficiency and position nonlinearity are calculated for different electrode layers, patterns, and sizes, as well as the distance between the bottom microchannel plate (MCP) and induction layer. The position nonlinearity exhibits an approximately linear relationship with the electrode size and the distance between the bottom MCP and induction layer. By increasing the electrode area in the perimeter region and designing 2.2 mm square electrodes in the central region, a position nonlinearity of 3.36% with a distance of 5 mm between the bottom MCP and induction layer is achieved. The imaging performance of the six multilayer capacitive anodes is evaluated using a custom-designed detector prototype, and the experimental results validate the simulation results. The comprehensively optimized capacitive anode shows an imaging nonlinearity of 0.91% in the experiment. © 2024
  Accession Number: 20241515861844