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arXiv 2025年

作者： Liu, Jianing Ma, Yuelei Chen, Ziyang Li, Zhenyan Wang, Yi Guo, Baohong Han, Dong Li, Yuanjing Key Laboratory of Particle and Radiation Imaging Department of Engineering Physics Tsinghua University Beijing100084 China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of China Hefei230026 China Modern Physics Department University of Science and Technology of China Hefei230026 China

This study focuses on developing a self-triggered data acquisition system and a noise reduction algorithm for the Multi-gap Resistive Plate Chamber (MRPC) Time-of-Flight Positron Emission Tomography (TOF-PET) system. The system integrates a fast front-end amplifier, a waveform digitization module based on the DRS4 chip, and an efficient noise reduction algorithm to address challenges such as high noise trigger rates and precise gamma-ray detection. The proposed self-triggered system, through threshold discrimination, coincidence logic, and continuous oscillation check, reduces the noise trigger rate to 0.004 Hz. Experimental results show that the system accurately localizes and images the 22Na radioactive source, and has a good time resolution of 162 ps FWHM for 0.511 MeV gamma rays. Copyright © 2025, The Authors. All rights reserved.

关键词： Gamma rays

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An alternative application of GaAs-based light-emitting diodes: X-ray detection and imaging

arXiv

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arXiv 2025年

作者： Yu, Quan Wang, Fangbao Yuan, Xin Liu, Ying Gan, Lianghua Xu, Gangyi Shen, Wenzhong Chen, Liang Zhang, Yueheng Key Laboratory of Artificial Structures and Quantum Control School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Radiation Detection Research Center Northwest Institute of Nuclear Technology Xi’an710024 China Key Laboratory of Infrared Imaging Materials and Detectors Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai200083 China Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou310024 China

GaAs-based light-emitting diodes (LEDs) are commonly employed in a variety of applications, including medical imaging, biosensing, optical communications, and night vision. In this paper, we present an alternative application of GaAs-based LED with SI-GaAs substrate for X-ray detection and imaging. The mechanism relies on the semiconductor frequency down-conversion process, where the SI-GaAs substrate acts as a photodetector (PD). Upon X-ray irradiation, the generated photocurrent by the SI-GaAs substrate drives the LED to emit NIR photons which can be detect by a low-cost CCD. We demonstrate direct X-ray detection and present preliminary imaging results, providing another example of the applicability of the PD-LED design for optical frequency conversion. The proposed LED X-ray detector leverages mature materials and fabrication processes. The application of the frequency down-conversion concept makes it possible for pixel-less imaging using a large single imaging unit, eliminating the need for readout circuits. This PD-LED architecture offers an alternative approach to direct X-ray detection and imaging, characterized by higher absorption, improved image resolution, and enhanced material stability. Copyright © 2025, The Authors. All rights reserved.

关键词： III-V semiconductors

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A quasi-optimal stacking method for up-the-ramp readout images

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Astronomical Techniques and Instruments 2025年第2期2卷 119-126页

作者： Guanghuan Wang Hu Zhan Zun Luo Chengqi Liu Youhua Xu Chun Lin Yanfeng Wei Wenlong Fan Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 101408China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China National Key Laboratory of Infrared Detection Technologies Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China Shanghai Institute of Technical Physics Chinese Academy of SciencesShanghai 200083China

A detector's nondestructive readout mode allows its pixels to be read multiple times during integration,enabling generation of a series of"up-the-ramp"images that continuously accumulate photons between successive *** noise is correlated across these images,optimal stacking generally requires the images to be weighted unequally to achieve the best possible target signal-to-noise ratio(SNR).Objects in the sky present wildly varied brightness characteristics,and the counts in individual pixels of the same object can also span wide ***,a single set of weights cannot be optimal in all *** ensure that the stacked image is easily calibratable,we apply the same weight to all pixels within the same *** practice,results for high-SNR cases degraded only slightly when we used weights derived for low-SNR cases,whereas the low-SNR cases remained more sensitive to the ***,we propose a quasi-optimal stacking method that maximizes the stacked SNR for the case where the RSN=1 per pixel in the last frame and use simulated data to demonstrate that this approach enhances the SNR more strongly than the equal-weight stacking and ramp fitting ***,we estimate the improvements in the limiting magnitudes for the China Space Station Telescope using the proposed *** compared with the conventional readout mode,which is equivalent to selecting the last frame from the nondestructive readout,stacking 30 up-the-ramp images can improve the limiting magnitude by approximately 0.5 mag for the telescope's near-infrared observations,effectively reducing readout noise by approximately 62%.

关键词： Astronomical detectors infrared observatories Astronomy data reduction Astronomy image processing

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Application of high adaptive models in building damage assessment: Case studies of earthquake in Turkey and hurricane in Louisiana

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Journal of Applied Remote Sensing 2025年第1期19卷

作者： Li, Pei Dong, Zhao Su, Xinyu Hu, Zhengsheng Su, Qun Wang, Huaying Zhang, Zuoheng Cao, Binghan Wang, Tao Hebei University of Engineering School of Mathematics and Physics Science and Engineering Handan China Hebei Computational Optical Imaging and Photoelectric Detection Technology Innovation Center Handan China Hebei International Joint Research Center for Computational Optical Imaging and Intelligent Sensing Handan China China Meteorological Administration National Satellite Meteorological Center National Center for Space Weather Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites Beijing China Beijing China

Rapid damage assessment after disasters is crucial for humanitarian relief and emergency response. The abrupt and unpredictable nature of disasters causes variations in the time, location, and sensors used for image collection, resulting in significant data disparities in satellite imagery. This poses a significant challenge for assessment tasks. To enable a rapid response, training models from scratch using a sufficient amount of on-site data is impractical due to time constraints. Thus, in practical applications, a model with robust adaptability and generalization is essential for autonomously adjusting to data variations. However, the majority of current models are trained and tested on a singular dataset, neglecting the aforementioned issues. To address these challenges, this study created datasets from the Turkey earthquake with large and dense building features and introduced datasets from the Louisiana hurricane with small and sparse building features. These datasets exhibit significant style differences and cover a broader range of building characteristics, providing a comprehensive evaluation of the model's adaptability. In the building damage assessment task, the model is trained on public datasets and validated using the newly introduced scenario data. Compared with existing assessment models, the U-net model demonstrates the highest adaptability performance in objectively evaluating damage levels. © 2024 Society of Photo-Optical Instrumentation Engineers (SPIE).

关键词： Emergency services

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Structural Damage detection and Localization Using Response Difference Transmissibility

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Journal of Shanghai Jiaotong university(Science) 2024年第6期29卷 1126-1138页

作者： WANG Zengwei DING Lei Shanghai Institute of Technical Physics Key Laboratory of Infrared System Detection and Imaging TechnologyChinese Academy of SciencesShanghai 200083China

In this paper,a novel method is proposed for structural damage detection and *** key of the proposed method is the use of the response difference transmissibility(RDT)for damage *** RDT is defined to relate response differences of the system to be evaluated and those of the original *** invariance properties of RDT are also *** on this,a damage indicator is proposed,and the benefits are verified by a numerical ***,the proposed method is illustrated and validated by finite element simulations and experimental case studies.

关键词： damage detection damage localization transmissibility mechanical vibrations

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A Quasi-Optimal Stacking Method for Up-the-Ramp Readout Images

arXiv

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arXiv 2025年

作者： Wang, Guanghuan Zhan, Hu Luo, Zun Liu, Chengqi Xu, Youhua Lin, Chun Wei, Yanfeng Fan, WenLong Key Laboratory of Space Astronomy and Technology National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China University of Chinese Academy of Sciences Beijing101408 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China National Key Laboratory of Infrared Detection Technologies Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai200083 China Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai200083 China

The non-destructive readout mode of a detector allows its pixels to be read multiple times during integration, generating a series of "up-the-ramp" images that keep accumulating photons between successive frames. Since the noise is correlated across these images, an optimal stacking generally requires weighting them unequally to achieve the best signal-to-noise ratio (SNR) for the target. Objects in the sky show wildly different brightness, and the counts in the pixels of the same object also span a wide range. Therefore, a single set of weights cannot be optimal for all cases. To keep the stacked image more easily calibratable, however, we choose to apply the same weight to all the pixels in the same frame. In practice, we find that the results of high-SNR cases degrade only slightly by adopting weights derived for low-SNR cases, whereas the low-SNR cases are more sensitive to the weights applied. We therefore propose a quasi-optimal stacking method that maximizes the stacked SNR for the case of SNR=1 per pixel in the last frame and demonstrate with simulated data that it always enhances the SNR more than the equal-weight stacking method and the ramp fitting method. Furthermore, we give an estimate of the improvement of limiting magnitudes for the China Space Station Telescope (CSST) based on this method. Compared with the conventional readout mode, which is equivalent to taking the last frame of the non-destructive readout, stacking 30 up-the-ramp images can improve the limiting magnitude by about 0.5 mag for CSST near-infrared observations, effectively reducing the readout noise by about 62%. © 2025, CC BY.

关键词： Image enhancement

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Feature Enhancement Network for infrared Small Target detection in Complex Backgrounds Based on Multi-Scale Attention Mechanism

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Applied Sciences (Switzerland) 2025年第9期15卷

作者： Zhang, Sen Du, Weilin Liu, Yuan Zhou, Ni Li, Zheng Key Laboratory of Infrared System Detection and Imaging Technology Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai200083 China University of Chinese Academy of Sciences Beijing100049 China

The identification of tiny objects via single-frame infrared is a significant challenge in computer vision, primarily due to large variances in target dimensions, overcrowded backgrounds, suboptimal signal-to-noise ratios, the propensity of bounding box regression to vary with target size, and potential partial occlusion scenarios. Addressing these challenges, we propose a sturdy network for enhancing features in the infrared detection of small targets utilizing multi-scale attention. In particular, the introduction of the Iterative Attentional Feature Fusion (iAFF) module at the detection network’s neck aims to tackle the issue of minor target features being overshadowed in the process of cross-scale feature fusion. Additionally, we present the Occlusion-Aware Attention Module (OAAM), which demonstrates greater tolerance for target localization errors in regions where local features are missing due to partial occlusion. By combining the scale and spatial attention mechanisms of the Dynamic Head, our approach adaptively learns the relative importance of different semantic layers. Furthermore, the integration of Normalized Wasserstein–Gaussian Distance (NWD) aims to tackle the convergence issues associated with the increased sensitivity of bounding box regression in identifying minor infrared targets. For assessing our technique’s efficiency, we present a novel benchmark dataset, IRMT-UAV, noted for its considerable discrepancies in target size, intricate backdrops, and substantial variations in the signal-to-noise ratio. The outcomes of our experiments using the public IRSTD-1k dataset and the internally developed IRMT-UAV dataset reveal that our technique surpasses cutting-edge (SOTA) methods, with mAP50 enhancements of 1.4% and 4.9%, respectively, thus proving our method’s efficiency and sturdiness. © 2025 by the authors.

关键词： Radar target recognition

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Observation of the interaction between Au− and CO2 in Au(CO2)n− anions: Physisorption as the dominant mechanism

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Journal of Chemical Physics 2025年第17期162卷 174310页

作者： Guo, Zonghui Du, Shihu Huang, Wei Zhao, Wenbao Han, Haiyan Zhao, Zhi Yan, Yongliang Fan, Zhihui Shi, Ruili Xie, Hua Jiang, Ling School of Mathematics and Physics Science and Engineering Hebei Computational Optical Imaging and Photoelectric Detection Technology Innovation Center Hebei International Joint Research Center for Computational Optical Imaging and Intelligent Sensing Hebei University of Engineering Handan056038 China School of Chemistry and Chemical Engineering Shandong University Jinan250100 China State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian116023 China

In this study, we investigated the structure and bonding of Au(CO2)n− (n = 2, 3) using photoelectron spectroscopy analysis, quantum chemical calculations, and weak interaction analysis. Quantum chemical calculations revealed that the geometries of the physisorbed structures closely aligned with experimental data, suggesting that these configurations were the most stable under the experimental conditions. Conversely, while chemisorbed structures exhibit stronger interactions and considerable CO2 activation, they show less agreement with the observed spectroscopic data. Using the interaction region indicator method, our weak interaction analysis confirmed that van der Waals forces were the dominant interaction in the physisorbed structures. Our experimental results indicate that these physically adsorbed structures are more stable under the conditions of this study. These findings shed light on the interaction mechanisms of Au(CO2)n− (n = 2, 3) at the molecular level and provide new insights into the potential for transition metals to catalytically activate CO2 © 2025 Author(s).

关键词： Van der Waals forces

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A novel method of spike detection for interferograms based on two-step filtering

A novel method of spike detection for interferograms based o...

引用

4th International Conference on Frontiers of Manufacturing Science and Measuring technology, ICFMM 2014

作者： Zou, Yao Pu Han, Chang Pei Zhang, Lei Pan, Wen Gui Wang, Chao Key Laboratory of Infrared System Detection and Imaging Technology SITP UCAS China

ISBN: (纸本)9783038351924

According to the characteristics of interferogram, we design a new spike detection method, which firstly filters an interferogram with two different ways and then detects spikes based on both results. Theoretical analysis and computer simulation shows that this algorithm performs well in detecting spikes in any position of an interferogram with high accuracy, and can be easily implemented in hardware. © (2014) Trans Tech Publications, Switzerland.

关键词： Computer hardware

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Ultra-high-efficiency circularly polarized reflector based on the dislocated double rectangle arrays

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Optik 2025年 328卷

作者： Cheng, Bo Jiang, Botao Zou, Yuxiao Song, GuoFeng Postdoctoral Innovation Practice Base Chengdu Polytechnic 83 Tianyi Street Sichuan Chengdu610041 China Institute of Semiconductors Chinese Academy of Sciences Beijing100083 China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences Beijing100049 China Kunming Institute of Physics Yunnan Kunming650223 China National Key Laboratory of Infrared Detection Technologies Kunming Institute of Physics Yunnan Kunming650223 China

The chiral lasers that can directly generate the circularly polarized light have important applications in a variety of fields, such as optical communications, biomedicine, materials processing, and optical measurements, and they are rapidly becoming an offshoot of the new generation of smart optoelectronic devices. However, the performance of current circularly polarized lasers is still limited by the effective design of chiral nanostructures, and their circular dichroism (CD) generally does not exceed 5 %. With the powerful optical modeling capability of the COMSOL Multiphysics platform, we innovatively introduce two dislocated rectangular blocks to break the spatial symmetry of the metasurface and obtain a huge chirality (CD > 95 %). This is then combined with a cylindrical array to form a Fabry–Pérot (FP) resonant cavity corresponding to a typical optical ternary system, which pushes the peak reflectivity of the cascaded metasurface to 99.6 %. Our designed chiral cascade metasurfaces simultaneously satisfy the demanding requirements of high reflectivity and large circular dichroism, and are expected to replace the conventional multilayer distributed bragg reflectors (DBRs) in VCSELs, contributing to the further development of miniaturized chiral lasers. © 2025 Elsevier GmbH

关键词： Circular polarization

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