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GPU-accelerated three-dimensional reconstruction method of the Compton camera and its application in radionuclide imaging

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Nuclear Science and Techniques 2023年第4期34卷 54-68页

作者： Ren-Yao Wu Chang-Ran Geng Feng Tian Zhi-Yang Yao Chun-Hui Gong Hao-Nan Han Jian-Feng Xu Yong-Shun Xiao Xiao-Bin Tang Department of Nuclear Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Engineering Physics Tsinghua UniversityBeijing 100084China School of Environmental and Biological Engineering Nanjing University of Science and TechnologyNanjing 210094China JYAMS PET Research and Development Limited Nanjing 211100China

A novel and fast three-dimensional reconstruction method for a Compton camera and its performance in radionuclide imaging is proposed and analyzed in this study. The conical surface sampling back-projection method with scattering angle correction(CSS-BP-SC) can quickly perform the back-projection process of the Compton cone and can be used to precompute the list-mode maximum likelihood expectation maximization(LM-MLEM). A dedicated parallel architecture was designed for the graphics processing unit acceleration of the back-projection and iteration stage of the CSS-BP-SC-based LM-MLEM. The imaging results of the two-point source Monte Carlo(MC) simulation demonstrate that by analyzing the full width at half maximum along the three coordinate axes, the CSS-BP-SC-based LM-MLEM can obtain imaging results comparable to those of the traditional reconstruction algorithm, that is, the simple back-projection-based LM-MLEM. The imaging results of the mouse phantom MC simulation and experiment demonstrate that the reconstruction results obtained by the proposed method sufficiently coincide with the set radioactivity distribution, and the speed increased by more than 664 times compared to the traditional reconstruction algorithm in the mouse phantom experiment. The proposed method will further advance the imaging applications of Compton cameras.

关键词： Compton camera three-dimensional reconstruction Radionuclide imaging GPU

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All-optical object identification and threedimensional reconstruction based on optical computing metasurface

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Opto-Electronic Advances 2023年第12期6卷 5-14页

作者： Dingyu Xu Wenhao Xu Qiang Yang Wenshuai Zhang Shuangchun Wen Hailu Luo Laboratory for Spin Photonics School of Physics and ElectronicsHunan UniversityChangsha 410082China School of Physics and Chemistry Hunan First Normal UniversityChangsha 410205China.

Object identification and three-dimensional reconstruction techniques are always attractive research interests in machine vision,virtual reality,augmented reality,and biomedical engineering.Optical computing metasurface,as a two-dimensional artificial design component,has displayed the supernormal character of controlling phase,amplitude,polarization,and frequency distributions of the light beam,capable of performing mathematical operations on the input light field.Here,we propose and demonstrate an all-optical object identification technique based on optical computing metasurface,and apply it to 3D reconstruction.Unlike traditional mechanisms,this scheme reduces memory consumption in the processing of the contour surface extraction.The identification and reconstruction of experimental results from high-contrast and low-contrast objects agree well with the real objects.The exploration of the all-optical object identification and 3D reconstruction techniques provides potential applications of high efficiencies,low consumption,and compact systems.

关键词： object identification three-dimensional reconstruction optical computing metasurface

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Phase Error Compensation of three-dimensional reconstruction Combined with Hilbert Transform

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Computers, Materials & Continua 2021年第9期68卷 3121-3131页

作者： Tao Zhang Jie Shen Shaoen Wu School of Mechanical Engineering North China University of Water Conservancy and Hydroelectric PowerZhengzhou450045China Department of Computer Science Ball State UniversityMuncie47306INUSA

Nonlinear response is an important factor affecting the accuracy of three-dimensional image measurement based on the fringe structured light method.A phase compensation algorithm combined with a Hilbert transform is proposed to reduce the phase error caused by the nonlinear response of a digital projector in the three-dimensional measurement system of fringe structured light.According to the analysis of the influence of Gamma distortion on the phase calculation,the algorithm establishes the relationship model between phase error and harmonic coefficient,introduces phase shift to the signal,and keeps the signal amplitude constant while filtering out the DC component.The phase error is converted to the transform domain,and compared with the numeric value in the space domain.The algorithm is combined with a spiral phase function to optimize the Hilbert transform,so as to eliminate external noise,enhance the image quality,and get an accurate phase value.Experimental results show that the proposed method can effectively improve the accuracy and speed of phase measurement.By performing phase error compensation for free-form surface objects,the phase error is reduced by about 26%,and about 27%of the image reconstruction time is saved,which further demonstrates the feasibility and effectiveness of the method.

关键词： three-dimensional reconstruction structured light Hilbert transform phase compensation

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Evaluating the contribution of satellite measurements to the reconstruction of three-dimensional ocean temperature fields in combination with Argo profiles

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Acta Oceanologica Sinica 2022年第2期41卷 65-79页

作者： Jian Chen Hengqian Yan Senliang Bao Xindong Cui Chengzu Bai Huizan Wang Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China Beijing Institute of Applied Meteorology Beijing 100029China College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101China

Assimilation systems absorb both satellite measurements and Argo observations.This assimilation is essential to diagnose and evaluate the contribution from each type of data to the reconstructed analysis,allowing for better configuration of assimilation parameters.To achieve this,two comparative reconstruction schemes were designed under the optimal interpolation framework.Using a static scheme,an in situ-only field of ocean temperature was derived by correcting climatology with only Argo profiles.Through a dynamic scheme,a synthetic field was first derived from only satellite sea surface height and sea surface temperature measurements through vertical projection,and then a combined field was reconstructed by correcting the synthetic field with in situ profiles.For both schemes,a diagnostic iterative method was performed to optimize the background and observation error covariance statics.The root mean square difference(RMSD)of the in situ-only field,synthetic field and combined field were analyzed toward assimilated observations and independent observations,respectively.The rationale behind the distribution of RMSD was discussed using the following diagnostics:(1)The synthetic field has a smaller RMSD within the global mixed layer and extratropical deep waters,as in the Northwest Pacific Ocean;this is controlled by the explained variance of the vertical surface-underwater regression that reflects the ocean upper mixing and interior baroclinicity.(2)The in situ-only field has a smaller RMSD in the tropical upper layer and at midlatitudes;this is determined by the actual noise-to-signal ratio of ocean temperature.(3)The satellite observations make a more significant contribution to the analysis toward independent observations in the extratropics;this is determined by both the geographical feature of the synthetic field RMSD(smaller at depth in the extratropics)and that of the covariance correlation scales(smaller in the extratropics).

关键词： satellite measurements Argo three-dimensional reconstruction ocean temperature

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Computer assisted reconstruction of three-dimensional canal model of femur and design for custom-made stem

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Chinese Medical Journal 2004年第8期117卷 1265-1267页

作者：刘建国李冬松马卫华周振平徐莘香 Department of Orthopaedic Surgery First Teaching Hospital Jilin UniversityChangchun130021China

The maximum stem-cortical bone contact plays a dominant role in the long-term fixation of the prosthesis; narrowing stem-cortical bone space and the bony ingrowths reduces the reaction to debris due to wear, the particle flows caused by the wear debris, the bone resorption, and the growth of pseudomembrane. We realized that the endosteal contour varies significantly from person to person. Thus, only one common designed prosthesis is not sufficient to achieve a high degree of accuracy in terms of modelling the proximal femur, therefore computer-assisted reconstruction of a three-dimensional canal model of the femur is a very promising way to produce custom hip stem prostheses.

关键词： three-dimensional reconstruction computer-assisted design ·custom-made stem

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Visualization of nasal powder distribution using biomimetic human nasal cavity model

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Acta Pharmaceutica Sinica B 2024年第1期14卷 392-404页

作者： Jiawen Su Yan Liu Hongyu Sun Abid Naeem Huipeng Xu Yue Qu Caifen Wang Zeru Li Jianhua Lu Lulu Wang Xiaofeng Wang Jie Wu Lixin Sun Jiwen Zhang Zhigang Wang Rui Yang Li Wu Key Laboratory of Modern Preparation of TCM Ministry of EducationJiangxi University of Chinese MedicineNanchang 330004China Key Laboratory of Molecular Pharmacology and Drug Evaluation School of PharmacyMinistry of EducationYantai UniversityYantai 264005China Shanghai Institute of Materia Medica Chinese Academy of SciencesShanghai 201210China Nantong Haimen People’s Hospital Nantong 226199China Yangtze Delta Drug Advanced Research Institute Nantong 226126China Shenyang Pharmaceutical University Shenyang 110016China National Institutes for Food and Drug Control Beijing 100000China Nanjing University of Chinese Medicine Nanjing 210023China

Nasal drug delivery efficiency is highly dependent on the position in which the drug is deposited in the nasal cavity.However,no reliable method is currently available to assess its impact on delivery performance.In this study,a biomimetic nasal model based on three-dimensional(3D)reconstruction and three-dimensional printing(3DP)technology was developed for visualizing the deposition of drug powders in the nasal cavity.The results showed significant differences in cavity area and volume and powder distribution in the anterior part of the biomimetic nasal model of Chinese males and females.The nasal cavity model was modified with dimethicone and validated to be suitable for the deposition test.The experimental device produced the most satisfactory results with five spray times.Furthermore,particle sizes and spray angles were found to significantly affect the experimental device’s performance and alter drug distribution,respectively.Additionally,mometasone furoate(MF)nasal spray(NS)distribution patterns were investigated in a goat nasal cavity model and three male goat noses,confirming the in vitro and in vivo correlation.In conclusion,the developed human nasal structure biomimetic device has the potential to be a valuable tool for assessing nasal drug delivery system deposition and distribution.

关键词： Nasal drug deposition Nasal drug distribution Nasal drug delivery Biomimetic nasal model Nasal powder three-dimensional reconstruction three-dimensional printing Nasal drug distribution

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Effects of the initiation position on the damage and fracture characteristics of linear-charge blasting in rock

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 443-451页

作者： Chenxi Ding Renshu Yang Xiao Guo Zhe Sui Chenglong Xiao Liyun Yang School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China State Key Lab of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

To study the effects of the initiation position on the damage and fracture characteristics of linear-charge blasting, blasting model experiments were conducted in this study using computed tomography scanning and three-dimensional reconstruction methods. The fractal damage theory was used to quantify the crack distribution and damage degree of sandstone specimens after blasting. The results showed that regardless of an inverse or top initiation, due to compression deformation and sliding frictional resistance, the plugging medium of the borehole is effective. The energy of the explosive gas near the top of the borehole is consumed. This affects the effective crushing of rocks near the top of the borehole, where the extent of damage to Sections Ⅰ and Ⅱ is less than that of Sections Ⅲ and Ⅳ. In addition, the analysis revealed that under conditions of top initiation, the reflected tensile damage of the rock at the free face of the top of the borehole and the compression deformation of the plug and friction consume more blasting energy, resulting in lower blasting energy efficiency for top initiation. As a result, the overall damage degree of the specimens in the top-initiation group was significantly smaller than that in the inverse-initiation group. Under conditions of inverse initiation, the blasting energy efficiency is greater, causing the specimen to experience greater damage. Therefore, in the engineering practice of rock tunnel cut blasting, to utilize blasting energy effectively and enhance the effects of rock fragmentation, using the inverse-initiation method is recommended. In addition, in three-dimensional(3D) rock blasting, the bottom of the borehole has obvious end effects under the conditions of inverse initiation, and the crack distribution at the bottom of the borehole is trumpet-shaped. The occurrence of an end effect in the 3D linear-charge blasting model experiment is related to the initiation position and the blocking condition.

关键词： blasting linear charge initiation position computed tomography three-dimensional reconstruction damage

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Compression behavior of metal foams with real pore structures through CT scan images

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Journal of Iron and Steel Research(International) 2022年第11期29卷 1886-1897页

作者： Lei Wang Kai Jiang Dong-hui Yang College of Mechanics and Materials Hohai UniversityNanjing 211100JiangsuChina Suqian Research Institute of Hohai University Suqian 223814JiangsuChina

Based on the real pore structure obtained from computed tomography(CT)scan images,a three-dimensional(3D)model of the metal foam sample with specified porosity is established,and the model is compressed and simulated by finite element method with the simulation results compared with the experimental test results for validation.At the same time,based on the spatial distribution characteristics of cells extracted from 3D model construction,a widely used metal foam model with Voronoi pore structure or spherical pore structure was established and simulated under compression.The two compression simulation results with regular pore structure models were also compared with the experimental results and CT model results to study the influence of cell wall morphology on the compression performance of metal foams.The simulation results show that CT model agrees well with the experimental results and is more accurate than Voronoi pore or spherical pore model,which can provide a more reasonable option for investigation of metal foams.

关键词： Metal foam Computed tomography scan three-dimensional reconstruction Cell wall morphology Compression performance

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Dynamic Volumography of Cylindrical Li-Ion Battery Cells by Watching Its Breath During Cycling

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CCS Chemistry 2023年第6期5卷 1308-1317页

作者： Wenxuan Jiang Haoran Li Sicong Wang Sa Wang Wei Wang State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023

It has been well-documented that the charging of Li-ion battery(LIB)is accompanied by volume expansion,a significant source of their capacity fading and structural failure.However,existing operando techniques for measuring battery expansion either use single-point detection to report the local deformation or are not sensitive enough for hard-pack cylindrical batteries.Here,we propose an optical volumography(OVG)technology,including both apparatus and methodology,to measure the absolute volume of a commercial 18650 cylindrical LIB cell by taking a series of optical images of a rotating battery and reconstructing its 3D surface profile.Charging(discharging)induced volume expansion(shrinkage),i.e.,the“breath,”of multiple battery cells can be quantitatively determined in parallel and in real time.This method has a sensitivity of up to 1×10^(−5)(ΔV/V0)and an accuracy of 0.1μm.In contrast to the overall expansion of a soft-pack pouch battery,hard-pack cylindrical cells exhibit rather small and heterogeneous wrinkle-type deformation during charging,underscoring the value of the sensitivity and spatial resolution of OVG.In addition to mapping the strain distribution,OVG further allows for differentiating the thermal-induced expansion from the reaction-induced expansion and evaluation of the state-of-charge and the state-of-health optically,with promising implications for process optimization,quality control,and energy and thermal management of batteries.

关键词： lithium-ion battery optical imaging in operando three-dimensional reconstruction high throughput

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Biochemical, molecular, and morphological variations of flight muscles before and after dispersal flight in a eusocial termite, Reticulitermes chinensis

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Insect Science 2021年第1期28卷 77-92页

作者： Zhen-Yu Zhang Jing Ren Fei Chu Jun-Xia Guan Guang-Yu Yang Yu-Tong Liu Xin-Ying Zhang Si-Qin Ge Qiu-Ying Huang Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhanChina Key Laboratory of Zoological Systematics and Evolution Institute of ZoologyChinese Academy of SciencesBeijingChina

Swarming behavior facilitates pair formation,and therefore mating,in many eusocial termites.However,the physiological adjustments and morphological transformations of the flight muscles involved in flying and flightless insect forms are still unclear.Here,we found that the dispersal flight of the eusocial termite Reticulitermes chinensis Snyder led to a gradual decrease in adenosine triphosphate supply from oxidative phospho・rylation,as well as a reduction in the activities of critical mitochondrial respiratory enzymes from preflight to dealation.Correspondingly,using three-dimensional reconstruction and transmission electron microscopy(TEM),the flight muscles were found to be gradually deteriorated during this process.In particular,two tergo-pleural muscles(IItpm5 and IIItpm5)necessary to adjust the rotation of wings for wing shedding behavior were present only in flying alates.These findings suggest that flight muscle systems vary in function and morphology to facilitate the swarming flight procedure,which sheds light on the important role of swarming in successful extension and fecundity of eusocial termites.

关键词： dispersal flight eusocial termite flight muscle mitochondrial oxidative phosphorylation swarming behavior three-dimensional reconstruction

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