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Spectral X-ray computed tomography image denoising using weighted local regression and noise-insensitive feature dimensionality reduction

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JOURNAL OF INSTRUMENTATION 2024年第8期19卷 P08020页

作者： Hotta, T. Yatagawa, T. Ohtake, Y. Matsukawa, M. Suzuki, H. Aoki, T. Shizuoka Univ Grad Sch Med Photon 3-5-1 JohokuChuo Ku Hamamatsu Shizuoka 4328011 Japan Hitotsubashi Univ Sch Social Data Sci 2-1 Naka Kunitachi Tokyo 1868601 Japan Univ Tokyo Dept Precis Engn 7-3-1 Hongo Bunkyo City Tokyo 1138654 Japan Zodiac Inc 145-1 TokiwachoChuo Ku Hamamatsu Shizuoka 4300917 Japan

This study introduces a novel denoising method for spectral X-ray computed tomography (CT) images using weighted local regression (WLR). The proposed method exploits the common structural information present across different energy bins. Denoised pixel intensities of a certain energy bin are estimated using the intensities of the other energy bins via WLR. Denoising is achieved by applying a WLR model to the noisy pixel intensities of all energy bins, excluding the target bin, which obtains approximate noise-free intensities for the target energy bin. The performance of our approach was assessed using synthetic spectral X-ray CT images produced using a Monte Carlo photon simulator called the Electron Gamma Shower 5 (EGS5). Both qualitative and quantitative evaluations demonstrated that our approach effectively reduced noise across all energy bins while maintaining image sharpness. Comparisons with common denoising methods demonstrate the effectiveness of the proposed method.

关键词： Analysis and statistical methods Computerized Tomography (CT) and Computed Radiography (CR) data processing methods Image filtering

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Burn-in test and thermal performance evaluation of Silicon Photomultipliers for the JUNO-TAO experiment

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JOURNAL OF INSTRUMENTATION 2024年第7期19卷 P07028页

作者： Chen, X. Cao, G. F. Qu, M. H. Wang, H. W. Anfimov, N. Rybnikov, A. Xu, J. Y. Su, A. Q. Chen, Z. L. Cao, J. Li, Y. C. Qi, M. Nanjing Univ 22 Hankou Rd Nanjing 210093 Jiangsu Peoples R China Chinese Acad Sci Inst High Energy Phys 19B Yuquan Rd Beijing 100049 Peoples R China Univ Chinese Acad Sci 1 Yanqihu East Rd Beijing 101408 Peoples R China Zhengzhou Univ 100 Sci Ave Zhengzhou 450001 Henan Peoples R China Joint Inst Nucl Res 6 Joliot Curie Str Dubna 141980 Moscow Russia

This study evaluates more than 4,000 tiles made of Hamamatsu visual-sensitive silicon photomultipier (SiPM), each with dimensions of 5 x 5 cm2, 2 , intended for the central detector of the Taishan Anti-neutrino Observatory (TAO), a satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO) aimed at measuring the reactor anti-neutrino energy spectrum with unprecedented energy resolution. All SiPM tiles underwent a room temperature burn-in test in the dark for two weeks, while cryogenic testing analyzed the thermal dependence of parameters for some sampled SiPMs. Results from these comprehensive tests provide crucial insights into the long-term performance and stability of the 10 square meters of SiPMs operating at -50 degrees C degrees C to detect scintillation photons in the TAO detector. Despite some anomalies awaiting further inspection, all SiPMs successfully passed the burn-in test over two weeks at room temperature, which is equivalent to 6.7 years at -50 degrees C. degrees C. Results are also used to guide optimal SiPM selection, configuration, and operation, ensuring reliability and sustainability in reactor neutrino measurements. This work also provides insights for a rapid and robust quality assessment in future experiments that employ large-scale SiPMs as detection systems.

关键词： Analysis and statistical methods Detector cooling and thermo-stabilization Large detector-systems performance data processing methods

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Neutron spectrum unfolding of EJ-276 plastic scintillator using MLEM and GRAVEL methods

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JOURNAL OF INSTRUMENTATION 2025年第4期20卷

作者： Wang, Mengmeng Fang, Meihua Li, Junyu Guo, Yi Li, Jia Feng Zhang, Ming Cai, Xinyi Wei, Zhiyong Nanjing Univ Aeronaut & Astronaut Sch Astronaut 29 Yudao St Nanjing 211106 Peoples R China Minist Ind & Informat Technol Key Lab Nucl Technol Applicat & Radiat Protect Ast Nanjing 211106 Peoples R China

Plastic scintillators with pulse shape discrimination (PSD) capabilities are widely used in neutron-gamma discrimination and neutron spectrum measurement due to their compact structure and ease of fabrication into various shapes and sizes. However, when neutrons scatter within plastic scintillators, the energy transfer distribution from neutrons to recoil particles during scattering and the dependence of detection efficiency on neutron energy, causes the neutron spectrum measured by the detector differs from the true incident neutron spectrum. Direct neutron spectrum measurements using plastic scintillator detectors can only discriminate neutron-gamma signals but the true neutron spectrum cannot be obtained. Therefore, this study focuses on demonstrating the capabilities of neutron spectrum measurement using unfolding methods with the EJ-276 plastic scintillator. The response spectra of the EJ-276 plastic scintillator, simulated using the Monte Carlo code Geant4, were corrected with light output and energy resolution functions to ensure consistency between the simulated and experimental spectra. These corrected spectra for a series of monoenergetic neutron sources were subsequently used to construct the detector response matrix. The pulse height distributions of 252Cf and 241Am-Be neutron sources were measured using the PSD method, and the PSD performance was evaluated through the Figure of Merit (FoM). At an energy threshold of 0.5 MeVee, the FoM values were 1.61 for 252Cf source and 1.67 for 241Am-Be source. Combining the detector response matrix, the measured neutron spectra were unfolded with the Maximum Likelihood Expectation Maximization (MLEM) and Gradient Vector Least Square (GRAVEL) methods and compared to the neutron spectra of ISO standard sources. The results indicate that the unfolded neutron spectra obtained through both methods show good agreement with the reference neutron spectra. For 252Cf and 241Am-Be sources, the MLEM method achieved Root Mean Sq

关键词： data processing methods Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc) Interaction of radiation with matter Scintillators, scintillation and light emission processes (solid, gas and liquid scintillators)

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The Comparison and Improvement of data processing methods in Video Quality Subjective Assessment

The Comparison and Improvement of Data Processing Methods in...

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International Congress on Image and Signal processing

作者： Shuang Yang Yifan Wang Fang Meng Xiuhua Jiang Hao Liu Inf. Eng. Sch. Commun. Univ. of China Beijing China

ISBN: (纸本)9781479958368

data screening applied in video quality subjective assessment is helpful to remove abnormal observers and ensure the precision and effectiveness of the results. This paper firstly introduces two main data-processing methods, which are recommended in ITU-R BT.500 and ITU-R BT.1788 respectively, and then proposes an improved data-processing method, which is used to eliminate observers whose score trends are inconsistent with the overall trend in the first stage and then eliminate observers with too many outliers. Finally we analyze the applicability of those data-processing methods and verify the effectiveness of the improved method.

关键词： data compression data handling observers video coding video signal processing ITU-R BT.1788 ITU-R BT.500 abnormal observer removal data processing methods data screening data-processing method video communications video compression video quality evaluation video quality subjective assessment video transmission Correlation Correlation coefficient Market research Observers Quality assessment Standards Video recording Pearson correlation coefficient Spearman rank correlation coefficient subjective assessment video quality

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Optimization of digital neutron-gamma discrimination methods in time and frequency domain

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JOURNAL OF INSTRUMENTATION 2024年第2期19卷 P02025页

作者： Singh, Harleen Mehra, and Rohit Kanya Maha Vidyalaya Dept Phys Jalandhar 144004 Punjab India Dr BR Ambedkar Natl Inst Technol Dept Phys Jalandhar 144011 Punjab India

Four digital methods are investigated for neutron -gamma discrimination in organic scintillation detectors. A fast -digital pulse processing system has been used to optimize the PSD methods and to investigate a mixed radiation field with light output in the range of 100 keV to 5 MeV from an Am -Be source. The methods used for pulse shape discrimination are the charge comparison, the simplified digital charge collection, the frequency gradient analysis, and the discrete wavelet transform method. The performance of each of these methods has been assessed by calculating the figure -of -merit and the probability of misclassification. It has been found that the frequency -domain algorithms perform more effectively for low -energy pulses and require a smaller processing gate width than the time -domain methods. They are therefore more suited to environments with high count rates where pulse pileup is a common attribute of data. In addition, frequency -domain methods are more resistant to random noise present in the dataset compared to time -domain methods.

关键词： data processing methods Digital signal processing (DSP) Liquid detectors Neutron detectors (cold thermal fast neutrons)

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An FPGA-based parallel deconvolution application envisaging high-energy calorimeters operating under severe pile-up conditions

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JOURNAL OF INSTRUMENTATION 2024年第8期19卷 P08022页

作者： Luz, Igo A. S. Simas, Eduardo F. Farias, Paulo C. M. A. de Andrade, Luciano M. Seixas, J. M. Fed Inst Bahia Rua Viriato Lobo Santo Antonio De Jesus BA Brazil Univ Fed Bahia Elect Engn Program Digital Syst Lab Rua Prof Aristides Novis Salvador BA Brazil Fed Univ Juiz de Fora UFJF Dept Elect Engn Rua Jose Lourenco Kelmer S-N Juiz De Fora MG Brazil Univ Rio de Janeiro Coppe Poli Ave Horacio Macedo Rio De Janeiro Brazil

Signal pileup may arise when the system response time is larger than what would be required by the event rate in the application. In this condition, information superposition occurs, and signal estimation is deteriorated due to such information distortion. For online applications, mitigating such a pileup distortion usually requires embedded digital signal processing, which often involves FPGAbased designs when high event rates are a concern. Recently, high-energy particle experiments started facing an unprecedented increase in pileup conditions, which demanded new approaches for signal estimation. This work proposes a dedicated parallel signal processing system embedded on an FPGA platform that implements different filtering techniques for online energy reconstruction in calorimeters (energy measurement) operating under severe pileup conditions. Each designed filter is an inverse approximation of the calorimeter readout channel's impulse response, performing deconvolution of the incoming signals. Such a deconvolution approach for energy estimation was recently introduced, and the proposed filters were implemented in this work. Evaluation of the digital system design was performed using a data set that considers a typical high-energy calorimeter front-end response, as high-luminosity particle collider experiments produce high pileup distortions in calorimeter signals when processing the subproducts of the collisions. As the Large Hadron Collider (LHC) provides the most demanding conditions in terms of signal pileup, the acquisition system of the proposed solution is synchronous with its collision rate (40 MHz). The results showed that the proposed implementation may be applied as a preprocessing (pileup reduction) step in calorimeter instrumentation and could reduce the signal pileup within the fast response time required by such experiments.

关键词： data processing methods Digital signal processing (DSP) VLSI circuits Calorimeters

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Synthesising two-dimensional mammographic images using compressed sensing-reconstructed digital breast tomosynthesis images

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JOURNAL OF INSTRUMENTATION 2024年第8期19卷 P08012页

作者： Han, Seohee Yang, Hyesun Xu, Wenting Seo, Changwoo Cho, Hyosung Cha, Bo Kyung Yonsei Univ Dept Radiat Convergence Engn Wonju South Korea Korea Electrotechnol Res Inst Precis Med Device Res Ctr Ansan South Korea

This study presents a method synthesizing a two-dimensional (2D) mammographic image of reasonable quality directly from a 3D digital breast tomosynthesis (DBT) image, reconstructed using an advanced compressed sensing (CS)-based algorithm. This approach aims to reduce the radiation dose required for complementary imaging technologies of digital mammography (DM) and DBT, eliminating the need for additional DM examinations. The method involves three main steps: projection data acquisition from a DBT system, CS-based DBT reconstruction, and synthesis of a 2D mammographic image from the reconstructed DBT image. To verify the efficacy of the proposed method, we conducted both a simulation and an experiment on a numerical breast and commercially available BR3D phantoms, respectively, prior to practical implementation in real-world DBT systems. Our simulation and experimental results indicated that the CS-based algorithm yielded markedly improved DBT reconstruction quality, preserving superior image homogeneity, better edge contour and sharpening, and fewer image artifacts. The measured contrast-to-noise ratio and structural similarity values of the CS-reconstructed DBT images were 10.31 and 0.78, respectively, which were approximately 2.2 and 3.1 times larger, respectively, than those of the filtered-backprojectionreconstructed DBT images in the simulation. The quality of the synthetic mammographic images using the CS-reconstructed DBT images was similar to that of conventional mammographic images obtained using a full dose, indicating the efficacy of the proposed method. Consequently, we successfully reconstructed DBT images of substantially high quality using the CS-based algorithm and synthesised 2D mammographic images of reasonable quality, potentially reducing the radiation dose to patients in the complementary imaging technologies of DM and DBT.

关键词： data processing methods Medical-image reconstruction methods and algorithms, computer-aided diagnosis X-ray mammography and scinto- and MRI-mammography

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Track reconstruction for the COMET Phase-II experiment with ACTS

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JOURNAL OF INSTRUMENTATION 2024年第1期19卷 P01011页

作者： Razquin, Amaia Lee, Myeongjae Sungkyunkwan Univ Dept Phys Suwon 16419 South Korea Karl Franzens Univ Graz Inst Phys A-8010 Graz Austria

An implementation of A Common Tracking Software (ACTS) toolkit for signal electron reconstruction for the COMET muon to electron conversion experiment is discussed. The COMET experiment in J-PARC, Japan, will search for neutrinoless conversion of muons into electrons in the field of an aluminium nucleus, a lepton flavour violating process, aiming target sensitivity of 10-17. To achieve its scientific goals, the experiment requires a reconstructed momentum resolution of lower than 150 keV/c. For the first time by applying ACTS to signal events in the 100 MeV energy range with multiple -turn trajectories in the presence of background events, it is found that the reconstruction efficiency is around 14% with no fake reconstructed events. The implementation details, performance, and issues of ACTS in the context of COMET are presented.

关键词： data processing methods Large detector-systems performance Pattern recognition cluster finding calibration and fitting methods

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A new method for evaluating the stability of radon concentration in a radon chamber

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JOURNAL OF INSTRUMENTATION 2023年第7期18卷 P07045-P07045页

作者： Feng, Yangyang Zhang, Xiongjie Zhang, Yan Zhang, Ye Tian, Xingyu Huang, Rengui Cao, Jie Tang, Bin East China Univ Technol Engn Res Ctr Nucl Technol Applicat Minist Educ Nanchang 330013 Peoples R China East China Univ Technol Sch Nucl Sci & Engn Nanchang 330013 Peoples R China CEA First Monitoring & Applicat Ctr Tianjin 300180 Peoples R China Earthquake Adm Jiangxi Prov Nanchang 330039 Peoples R China

Evaluation of the stability of radon concentration in a radon chamber is a critical part of the quality controls of a radon chamber to ensure the better performance. However, the existing evaluation method focus on giving the relative percentage difference between the individual observation value and the reference average. This index only reflects the evaluation results of short-term measurements and fails to provide available information that reflects the long-term stability of observation data. This paper presents a new evaluation method, Trend Analysis. The proposed method allowed to give a quick response to trend changes and abnormal results in observation data to find out the time interval that required special concern. Two stability tests were conducted in the HD-6 multi-functional radon chamber, and the results obtained from this method application were presented. In two tests, the radon concentration in the radon chamber was measured for 72 hours. The first 24 hours of observation data were used to analyze the stability, and the following 48 hours of observation data were used to verify the analysis results. Compared with the existing method, the evaluation method proposed in this paper increases the recognition of trends in observation data, thereby further predicting anomalies in subsequent data. Tests have proved that this method is very useful for evaluating the stability of radon concentration in a radon chamber.

关键词： Analysis and statistical methods data processing methods Radon chamber Stability Metrology and data analysis

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Particle flow reconstruction for the CMS Phase-II Level-1 Trigger

Particle flow reconstruction for the CMS Phase-II Level-1 Tr...

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Topical Workshop on Electronics for Particle Physics (TWEPP)

作者： Herwig, C. Fermilab Natl Accelerator Lab POB 500 Batavia IL 60510 USA

The upgrade of the CMS detector for the high-luminosity LHC will include track-finding for the first time in the Level-1 trigger, enabling Particle Flow reconstruction of every event in addition to comprehensive pileup mitigation. The Correlator trigger will reconstruct isolated leptons and photons, hadronic jets, and energy sums, assisted in many cases by machine learning to benefit from the complete particle-level event record. We present the logic of these algorithms, possible implementations using large FPGAs and their demonstration in prototype hardware, in addition to the expected physics performance.

关键词： Trigger algorithms Trigger concepts and systems (hardware and software) data processing methods

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