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CMA:an efficient index algorithmof clustering supporting fast retrieval oflarge image databases
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作者 谢毓湘 栾悉道 +2 位作者 吴玲达 老松杨 谢伦国 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第3期709-714,共6页
To realize content-hased retrieval of large image databases, it is required to develop an efficient index and retrieval scheme. This paper proposes an index algorithm of clustering called CMA, which supports fast retr... To realize content-hased retrieval of large image databases, it is required to develop an efficient index and retrieval scheme. This paper proposes an index algorithm of clustering called CMA, which supports fast retrieval of large image databases. CMA takes advantages of k-means and self-adaptive algorithms. It is simple and works without any user interactions. There are two main stages in this algorithm. In the first stage, it classifies images in a database into several clusters, and automatically gets the necessary parameters for the next stage-k-means iteration. The CMA algorithm is tested on a large database of more than ten thousand images and compare it with k-means algorithm. Experimental results show that this algorithm is effective in both precision and retrieval time. 展开更多
关键词 large image database content-based retrieval K-means clustering self-adaptive clustering.
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Numerical simulation for large baseline interferometric imaging altimeter
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作者 Jie Liu Bo Liu +2 位作者 Xiaonan An Haifeng Kou Bing Li 《Geodesy and Geodynamics》 2025年第1期111-126,共16页
Sea topography information holds significant importance in oceanic research and the climate change detection.Radar imaging altimetry has emerged as the leading approach for global ocean observation,employing synthetic... Sea topography information holds significant importance in oceanic research and the climate change detection.Radar imaging altimetry has emerged as the leading approach for global ocean observation,employing synthetic aperture radar(SAR)interferometry to enhance the spatial resolution of Sea topography.Nevertheless,current payload capacity and satellite hardware limitations prevent the extension of the interferometric baseline by enlarging the physical antenna size.This constraint hinders achieving centimeter-level accuracy in interferometric altimetry.To address this challenge,we conducted a numerical simulation to assess the viability of a large baseline interferometric imaging altimeter(LB-IIA).By controlling the baseline within the range of 600-1000 m through spiral orbit design in two satellites and mitigating baseline de-correlation with the carrier frequency shift(CFS)technique,we aimed to overcome the above limitations.Our findings demonstrate the efficacy of the CFS technique in compensating for baseline decoherence,elevating coherence from less than 0.1 to over 0.85.Concurrently.The height difference accuracy between neighboring sea surfaces reaches 1 cm within a 1 km resolution.This study is anticipated to serve as a foundational reference for future interferometric imaging altimeter development,catering to the demand for high-precision sea topography data in accurate global bathymetry inversion. 展开更多
关键词 Sea topography Numerical simulation Carrier frequency shift(CFS) large baseline interferometric imaging altimeter(LB-IIA)
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Dataset of Large Gathering Images for Person Identification and Tracking
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作者 Adnan Nadeem Amir Mehmood +7 位作者 Kashif Rizwan Muhammad Ashraf Nauman Qadeer Ali Alzahrani Qammer H.Abbasi Fazal Noor Majed Alhaisoni Nadeem Mahmood 《Computers, Materials & Continua》 SCIE EI 2023年第3期6065-6080,共16页
This paper presents a large gathering dataset of images extracted from publicly filmed videos by 24 cameras installed on the premises of Masjid Al-Nabvi,Madinah,Saudi Arabia.This dataset consists of raw and processed ... This paper presents a large gathering dataset of images extracted from publicly filmed videos by 24 cameras installed on the premises of Masjid Al-Nabvi,Madinah,Saudi Arabia.This dataset consists of raw and processed images reflecting a highly challenging and unconstraint environment.The methodology for building the dataset consists of four core phases;that include acquisition of videos,extraction of frames,localization of face regions,and cropping and resizing of detected face regions.The raw images in the dataset consist of a total of 4613 frames obtained fromvideo sequences.The processed images in the dataset consist of the face regions of 250 persons extracted from raw data images to ensure the authenticity of the presented data.The dataset further consists of 8 images corresponding to each of the 250 subjects(persons)for a total of 2000 images.It portrays a highly unconstrained and challenging environment with human faces of varying sizes and pixel quality(resolution).Since the face regions in video sequences are severely degraded due to various unavoidable factors,it can be used as a benchmark to test and evaluate face detection and recognition algorithms for research purposes.We have also gathered and displayed records of the presence of subjects who appear in presented frames;in a temporal context.This can also be used as a temporal benchmark for tracking,finding persons,activity monitoring,and crowd counting in large crowd scenarios. 展开更多
关键词 large crowd gatherings a dataset of large crowd images highly uncontrolled environment tracking missing persons face recognition activity monitoring
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Near-Range Large Field-of-View Three-Dimensional Photon-Counting Imaging with a Single-Pixel Si-Avalanche Photodiode 被引量:3
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作者 Guang-Yue Shen Tian-Xiang Zheng +4 位作者 Bing-Cheng Du Yang Lv E Wu Zhao-Hui Li Guang Wu 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第11期38-41,共4页
Large field-of-view(FoV) three-dimensional(3 D) photon-counting imaging is demonstrated with a single-pixel single-photon detector based on a Geiger-mode Si-avalanche photodiode. By removing the collecting lens(C... Large field-of-view(FoV) three-dimensional(3 D) photon-counting imaging is demonstrated with a single-pixel single-photon detector based on a Geiger-mode Si-avalanche photodiode. By removing the collecting lens(CL)before the detector, the FoV is expanded to ±10°. Thanks to the high detection efficiency, the signal-to-noise ratio of the imaging system is as high as 7.8 dB even without the CL when the average output laser pulse energy is about 0.45 pJ/pulse for imaging the targets at a distance of 5 m. A 3 D image overlaid with the reflectivity data is obtained according to the photon-counting time-of-flight measurement and the return photon intensity. 展开更多
关键词 Near-Range large Field-of-View Three-Dimensional Photon-Counting Imaging with a Single-Pixel Si-Avalanche Photodiode SI
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Mesoscopy: Innovations in high-resolution and large-field imaging
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作者 Xin Xu Jixiang Wang +4 位作者 Qin Luo Yahui Song Yi He Jing Lu Guohua Shi 《The Innovation》 2025年第6期15-16,共2页
Mesoscopy refers to imaging methodologies that provide a field of view(FOV)ranging from several millimeters to centimeters while achieving cellular or even subcellular resolution(Figure 1).This technological framework... Mesoscopy refers to imaging methodologies that provide a field of view(FOV)ranging from several millimeters to centimeters while achieving cellular or even subcellular resolution(Figure 1).This technological framework employs specially designed large-scale objective lenses to correct aberrations across extended FOVs,synchronized with light-field acquisition modalities through either scanning point detection or large-format array detection.Conventional microscopes,constrained by the limitations of objective lenses,exhibit a trade-off between the FOV and resolution.To achieve both high resolution and a large FOV,common approaches such as FOV stitching and Fourier ptychography were employed.However,these methods were extremely slow and imposed numerous constraints on samples.In 2016,a mesoscopic objective lens was introduced to address these challenges,achieving a 6 mm FOV and 0.7 mm resolution,thereby increasing the imaging throughput of conventional objective lenses by orders of magnitude.1 In the same year,this technology was recognized as one of the top ten physics breakthroughs worldwide by Physics World.Since then,mesoscopic imaging technology has gradually gained momentum and has been applied in various fields. 展开更多
关键词 high resolution imaging large field imaging Fourier ptychography mesoscopy objective lenses light field acquisition fov stitching imaging methodologies
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Compound eyes-on-a-chip for large field-of-view imaging and dynamic target positioning
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作者 Jiayi WAN Weijian ZHONG +3 位作者 Yuqing LIU Changxu LI Dongdong HAN Yonglai ZHANG 《Science China(Technological Sciences)》 2025年第10期255-265,共11页
Compound eyes(CEs),renowned for their extraordinary visual capabilities,offer significant potential for advanced micro-optical systems.However,their applications in wide field-of-view(FOV)imaging and dynamic tracking,... Compound eyes(CEs),renowned for their extraordinary visual capabilities,offer significant potential for advanced micro-optical systems.However,their applications in wide field-of-view(FOV)imaging and dynamic tracking,for instance,microscopic particle image velocimetry(μ-PIV)for microfluidics,remain constrained by limited spatial resolution.We present a compound eye-on-a-chip(CEoC)system integrating a seven-ommatidium CE with a microfluidic platform.When fabricated via femtosecond laser two-photon polymerization(TPP),the CE exhibits exceptional surface smoothness(<4 nm roughness)and achieves wide-FOV imaging(>120°)with submicrometer resolution.Through quantitative calibration using TPP-fabricated microstructures,we established precise 3D spatial positioning capabilities.Proof-of-conceptμ-PIV experiments using fluorescent microparticles successfully reconstructed high-speed trajectories(10 mm/s)from real-time CE-captured images.This integrated CEoC system has promising potential for advancing microfluidic analysis and optofluidic manipulation technologies. 展开更多
关键词 compound eye 3D imaging large field-of-view imaging microscopic particle image velocimetry CE-on-a-chip system
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Estimation of the turbulent viscous shear stress in a centrifugal rotary blood pump by the large eddy particle image velocimetry method 被引量:1
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作者 Jing-jing Ji Hao-yuan Li +2 位作者 Qing-yu Wu Yu Zhang Xian-wu Luo 《Journal of Hydrodynamics》 SCIE EI CSCD 2020年第3期486-496,共11页
The non-physiologic turbulent flows in centrifugal rotary blood pumps (RBPs) may result in complications such as the hemolysis and the platelet activation. Recent researches suggest that the turbulent viscous dissipat... The non-physiologic turbulent flows in centrifugal rotary blood pumps (RBPs) may result in complications such as the hemolysis and the platelet activation. Recent researches suggest that the turbulent viscous dissipation in the smallest eddies is the main factor of the blood trauma caused by the turbulent flow. The turbulent viscous shear stress (TVSS) was taken as the realistic physical force acting on the cells. However, limited by the temporal and spatial resolutions of the instrumentation currently available, very limited studies are available for the TVSS in the RBPs. In this paper, the large eddy particle image velocimetry (PIV) method is used to estimate the turbulent dissipation rate in the sub-grid scale, to investigate the effect of the TVSS on the blood trauma. Detailed flow characteristics, such as the relative velocity vectors, the estimated TVSS levels and the Kolmogorov length scales, are analyzed in three impeller phases at three constant flow rates (3 L/min, 5 L/min and 7 L/min). Over the measures range in this study, the maximum TVSS in the investigated RBP is lower than the reported critical value of stress. This study demonstrates that the large eddy PIV method is effective to evaluate the flow-dependent force on the cells. On the other hand, it is found that the TVSS is highly dependent on the flow behavior. Under severe off-design conditions, the complex flow characteristics, such as the flow separation and the vortical structures, will increase the TVSS. Thus, in order to reduce the hemolysis in the RBPs, the flow disturbance, induced by the departure of the incidence angle, should be avoided during the design of the RBPs. 展开更多
关键词 Rotary blood pump turbulent flow turbulent viscous shear stress large eddy particle image velocimetry flow separation
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Design and performance of air flow-assisted ionization imaging mass spectrometry system 被引量:2
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作者 Fei Tang Yi Chen +3 位作者 Jiu-Ming He Zhi-Gang Luo Zeper Abliz Xiao-Hao Wang 《Chinese Chemical Letters》 SCIE CAS CSCD 2014年第5期687-692,共6页
The imaging mass spectrometry(IMS) technology has experienced a rapid development in recent years.A new IMS technology which is based on air flow assisted ionization(AFAI) was reported.It allows for the convenient... The imaging mass spectrometry(IMS) technology has experienced a rapid development in recent years.A new IMS technology which is based on air flow assisted ionization(AFAI) was reported.It allows for the convenient pretreatment of the samples and can image a large area of sample in a single measurement with high sensitivity.The AFAI in DESI mode was used as the ion source in this paper.The new IMS method is named AFADESI-IMS.The adoption of assisted air flow makes the sample pretreatment easy and convenient.An optimization of the distance between the ion transport tube and MS orifice increases the sensitivity of the system.For data processing,a program based on MATLAB with the function of numerical analysis was developed.A theoretical imaging resolution of a few hundred microns can be achieved.The composite AFAI-IMS images of different target analytes were imaged with high sensitivity.A typical AFAI-IMS image of the whole-body section of a rat was obtained in a single analytical measurement.The ability to image a large area for relevant samples in a single measurement with high sensitivity and repeatability is a significant advantage.The method has enormous potentials in the MS imaging of large and complicated samples. 展开更多
关键词 Imaging mass spectrometry Air flow assisted ionization imaging mass spectrometry Whole-body imaging large and complicated sample imaging
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A Study of Animated Transition in Similarity-Based Tiled Image Layout
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作者 Huan Zhang Jun Tao +1 位作者 Fang Ruan Chaoli Wang 《Tsinghua Science and Technology》 SCIE EI CAS 2013年第2期157-170,共14页
For many information visualization applications, showing the transition when interacting with the data is critically important as it can help users better perceive the changes and understand the underlying data. In th... For many information visualization applications, showing the transition when interacting with the data is critically important as it can help users better perceive the changes and understand the underlying data. In this paper, we investigate the effectiveness of animated transition in a tiled image layout where the spiral arrangement of the images is based on their similarity. Three aspects of animated transition are considered, including animation steps, animation actions, and flying paths. Exploring and weighting the advantages and disadvantages of different methods for each aspect and in conjunction with the characteristics of the spiral image layout, we present an integrated solution, called AniMap, for animating the transition from an old layout to a new layout when a different image is selected as the query image. We show the effectiveness of our animated transition solution by demonstrating experimental results and conducting a comparative user study. 展开更多
关键词 animated transition image layout large image collections user study
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Scalable X-ray scintillators with bright singlet-triplet hybrid self-trapping excitons
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作者 Shi-Yu Song Chao-Jun Gao +7 位作者 Rui Zhou Bing-Zhe Wang Wen-Bo Zhao Qing Cao Yan-Wei Hu Lin Dong Kai-Kai Liu Chong-Xin Shan 《Light(Science & Applications)》 2025年第9期2616-2627,共12页
Size-scalable X-ray scintillators with high transparency and robust photon yield allow for imaging large objects with greater precision and detail.Solution-processable scintillators,typically crafted from quantum dots... Size-scalable X-ray scintillators with high transparency and robust photon yield allow for imaging large objects with greater precision and detail.Solution-processable scintillators,typically crafted from quantum dots(QDs),are promising candidates for highly efficient scintillation applications.However,the restricted size and low transparency in QD-based scintillators lead to less efficient X-ray imaging for large objects requiring high resolution.Herein,we demonstrate a meter-scale ZnO QD scintillator with a visible range transmittance exceeding 96%,featuring bright singlet-triplet hybrid self-trapping excitons(STEs).The quantum yields(QYs)of singlet excitons and triplet excitons are 44.7%and 26.3%.Benefiting from a large Stokes shift and bright triplet excitons,the scintillator has a negligible self-absorption and elevated photon yields.Additionally,the scintillator exhibits exchange invariance,demonstrating identical optical performance upon exchanging the coordinates(r)of the QDs.Featuring bright singlet-triplet hybrid STEs and high transparency,the scintillator achieves high resolution X-ray imaging of 42-line pairs per millimeter(42 lp mm^(-1))at a meter scale.Moreover,demonstrations of 5000 cm^(2) X-ray imaging and real-time dynamic X-ray imaging are presented.The lowest detectable dose rate for X-ray detection is as low as 37.63±0.4 nGy s^(-1).This work presents a novel sizable and transparent scintillator with bright singlet-triplet hybrid STEs,showcasing their potential in high-resolution and sizable object X-ray imaging. 展开更多
关键词 quantum dots zno qd scintillator high transparency quantum dots qds imaging large objects scalable scintillators photon yield singlet triplet hybrid self trapping excitons
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Subvoxel light-sheet microscopy for high-resolution high-throughput volumetric imaging of large biomedical specimens 被引量:7
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作者 Peng Fei Jun Nie +9 位作者 Juhyun Lee Yichen Ding Shuoran Li Hao Zhang Masaya Hagiwara Tingting Yu Tatiana Segura Chih-Ming Ho Dan Zhu Tzung KHsiaic 《Advanced Photonics》 EI CSCD 2019年第1期45-57,共13页
A key challenge when imaging whole biomedical specimens is how to quickly obtain massive cellular information over a large field of view(FOV).We report a subvoxel light-sheet microscopy(SLSM)method enabling high-throu... A key challenge when imaging whole biomedical specimens is how to quickly obtain massive cellular information over a large field of view(FOV).We report a subvoxel light-sheet microscopy(SLSM)method enabling high-throughput volumetric imaging of mesoscale specimens at cellular resolution.A nonaxial,continuous scanning strategy is developed to rapidly acquire a stack of large-FOV images with three-dimensional(3-D)nanoscale shifts encoded.Then,by adopting a subvoxel-resolving procedure,the SLSM method models these low-resolution,cross-correlated images in the spatial domain and can iteratively recover a 3-D image with improved resolution throughout the sample.This technique can surpass the optical limit of a conventional light-sheet microscope by more than three times,with high acquisition speeds of gigavoxels per minute.By fast reconstruction of 3-D cultured cells,intact organs,and live embryos,SLSM method presents a convenient way to circumvent the trade-off between mapping large-scale tissue(>100 mm3)and observing single cell(∼1-μm resolution).It also eliminates the need of complicated mechanical stitching or modulated illumination,using a simple light-sheet setup and fast graphics processing unit-based computation to achieve high-throughput,high-resolution 3-D microscopy,which could be tailored for a wide range of biomedical applications in pathology,histology,neuroscience,etc. 展开更多
关键词 light-sheet microscopy subvoxel-resolving reconstruction large tissue imaging high-throughput volumetric imaging
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3D depth-coded photoacoustic microscopy with a large field of view for human skin imaging 被引量:6
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作者 Zhongwen Cheng Haigang Ma +1 位作者 Zhiyang Wang Sihua Yang 《Chinese Optics Letters》 SCIE EI CAS CSCD 2018年第8期58-61,共4页
Photoacoustic (PA) microscopy comes with high potential for human skin imaging, since it allows noninvasively high-resolution imaging of the natural hemoglobin at depths of several millimeters. Here, we developed a ... Photoacoustic (PA) microscopy comes with high potential for human skin imaging, since it allows noninvasively high-resolution imaging of the natural hemoglobin at depths of several millimeters. Here, we developed a PA microscopy to achieve high-resolution, high-contrast, and large field of view imaging of skin. A three-dimensional (3D) depth-coding technology was used to encode the depth information in PA images, which is very intuitive for identifying the depth of blood vessels in a two-dimensional image, and the vascular structure can be analyzed at different depths. Imaging results demonstrate that the 3D depth-coded PA microscopy should be translated from the bench to the bedside. 展开更多
关键词 PA depth-coded photoacoustic microscopy with a large field of view for human skin imaging
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