- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2019
- 2018
- infrared image
- target detection
- lucas–kanade method (LK)
- local contrast method (LCM)
- facet model
- target detection
- zero-crossing point
- Image processing
- Infrared camera
- Eye movement
- Optoelectronic Information Science and Engineering
- Chinese Academy of Sciences
- Gunma University
- University of Chinese Academy of Science
- Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Science
- University of Science and Technology of China
- Space Star Technology Co. LTD
-
Dim and small infrared target fast detection guided by visual saliency
摘要： In order to detect dim and small infrared targets from a mass of high-resolution images of omni-directional Infrared Search and Track (IRST) systems rapidly and accurately, a fast target detection method guided by visual saliency (TDGS) is proposed. In this method, a coarse-to-fine detection strategy is used. First, in the stage of coarse-detection, according to the differences of global features between targets and backgrounds, a global saliency model based on fast spectral scale space (FSSS) is constructed to suppress complex background regions rapidly. And visual salient regions which contain dim and small targets are extracted from the original image. Then, in the stage of fine-detection, according to differences of local contrast between targets and background, an adaptive local contrast method (ALCM) is applied to finely improve contrast of targets in visual salient regions. Candidate targets can be further extracted through the adaptive threshold segmentation. Finally, dim and small targets are detected by their temporal relativity in multi-frames. Experimental results on four typical image sequences have indicated that the proposed method can not only detect dim and small infrared targets with small amount of computation, high detection probability, and low false alarm rate, but also adapt to various complex backgrounds. It is suitable for dim and small targets detection in omni-directional IRST systems and other practical applications.
关键词： Visual saliency,Coarse-to-fine detection strategy,Dim and small infrared target,Fast detection,Complex backgrounds
更新于2025-09-09 09:28:46
-
Rapid subtyping of pathogenic and nonpathogenic Vibrio parahaemolyticus by fourier transform infrared spectroscopy with chemometric analysis
摘要： Vibrio parahaemolyticus which naturally inhabits marine and estuarine environment represents pathogenic strains (virulence genes tdh or trh positive) and non-pathogenic strains (virulence genes negative). In this study, a rapid method for subtyping pathogenic and non-pathogenic V. parahaemolyticus was established using fourier transform infrared (FTIR) spectroscopy with chemometric analysis. This method targeted three strains of genotypes of V. parahaemolyticus including tdh positive, trh positive and virulence gene-negative (nonpathogenic) V. parahaemolyticus. The FTIR absorption spectra between 1800 and 900 cm?1 highlighted the most distinctive variations and were the most useful for characterizing the three bacteria. The successful differentiation and identification of the three bacteria could be accomplished in less than 1 h by FTIR using principal component analysis (PCA), or another cluster model of hierarchical cluster analysis (HCA). The method was verified by analyzing spiked V. parahaemolyticus fish samples. Furthermore, all of ten clinical isolates of V. parahaemolyticus were identified as tdh-positive, none of the clinical isolates were trh-positive, and all of ten environmental isolates were identified as non-pathogenic by the subtyping method, which were confirmed by PCR assays. All data demonstrated that the newly established subtyping method by FTIR is practical, time-saving, labor-saving, specific and cost-effective, especially suitable for the basic laboratories of CDC and port quarantine departments to perform suiveillance and epidemiological traceability of pathogenic V. parahaemolyticus.
关键词： Pathogenicity,Principal component analysis,Fourier transform infrared spectroscopy,Hierarchical cluster analysis,Vibrio parahaemolyticus,Subtype
更新于2025-09-09 09:28:46
-
Dynamic cortical connectivity alterations associated with Alzheimer's disease: An EEG and fNIRS integration study
摘要： Emerging evidence indicates that cognitive deficits in Alzheimer’s disease (AD) are associated with disruptions in brain network. Exploring alterations in the AD brain network is therefore of great importance for understanding and treating the disease. This study employs an integrative functional near-infrared spectroscopy (fNIRS) – electroencephalography (EEG) analysis approach to explore dynamic, regional alterations in the AD-linked brain network. FNIRS and EEG data were simultaneously recorded from 14 participants (8 healthy controls and 6 patients with mild AD) during a digit verbal span task (DVST). FNIRS-based spatial constraints were used as priors for EEG source localization. Graph-based indices were then calculated from the reconstructed EEG sources to assess regional differences between the groups. Results show that patients with mild AD revealed weaker and suppressed cortical connectivity in the high alpha band and in beta band to the orbitofrontal and parietal regions. AD-induced brain networks, compared to the networks of age-matched healthy controls, were mainly characterized by lower degree, clustering coefficient at the frontal pole and medial orbitofrontal across all frequency ranges. Additionally, the AD group also consistently showed higher index values for these graph-based indices at the superior temporal sulcus. These findings not only validate the feasibility of utilizing the proposed integrated EEG-fNIRS analysis to better understand the spatiotemporal dynamics of brain activity, but also contribute to the development of network-based approaches for understanding the mechanisms that underlie the progression of AD.
关键词： Alzheimer’s disease,Brain network,Functional near-infrared spectroscopy,Graph theory,EEG source imaging
更新于2025-09-09 09:28:46
-
Replacement Orthogonal Wavelengths Selection as a new method for multivariate calibration in spectroscopy
摘要： Wavelength selection is a critical step in multivariate calibration. Variable selection methods are used to find the most relevant variables, leading to improved prediction accuracy, while simplifying both the built models and their interpretation. In addition, different spectrophotometer designs and measurement principles result in non-destructive technologies applied in many fields, such as agriculture, food chemistry and pharmaceutics. However, an on-chip or portable device does not allow acquiring data from a large number of wavelengths. Therefore, the most informative combination of a limited number of variables should be selected. The Replacement Orthogonal Wavelengths Selection (ROWS) method is described here as a new method. This algorithm aims at selecting as few wavelengths as possible, while keeping or improving the prediction performance of the model, compared to when no variable selection is applied. The ROWS is applied to several near infrared spectroscopic data sets leading to improved analytical figures of merits upon wavelength selection in comparison to a built PLS model using entire spectral range. The performance of the ROWS-MLR method was compared to the FCAM-PLS method. The resulting models are not significantly different from those of FCAM-PLS; however, it involves a significantly smaller amount of variables.
关键词： Replacement Method,ROWS-MLR,Orthogonalization,FCAM-PLS,Near-Infrared spectroscopy
更新于2025-09-09 09:28:46
-
Imaging of endogenous hydrogen peroxide during the process of cell mitosis and mouse brain development with a near-infrared ratiometric fluorescent probe
摘要： Hydrogen peroxide (H2O2) is emerging as a new second messenger, which plays vital roles in intracellular signaling, thereby triggering physiological variations in terms of proliferation, differentiation, and migration. As known, cell mitosis has closely association to the intracellular level of H2O2, which contribute to the significant effects on the brain development, especially during the critical period of immaturity. Unfortunately, imaging H2O2 in mammalian brain is still challenging. Herein, to further investigate the biological roles of endogenous H2O2 in cells mitosis, we develop a near-infrared ratiometric fluorescent probe Cy-PFS for specifically imaging of endogenous H2O2 in cells and in vivo. Employing the probe Cy-PFS, we examine the critical effects of endogenous H2O2 on cells proliferation in live hippocampal neurons cells, our results provide strong evidences for H2O2 signaling in cell mitosis through growth factor signaling. Furthermore, we successfully demonstrate the close association of endogenous H2O2 level changes with the brain development at various stages. We envision that this present probe has potential as a promising useful chemical imaging tool for exploring the roles of H2O2 in cell mitosis.
关键词： cell mitosis,Hydrogen peroxide,endogenous H2O2,brain development,near-infrared ratiometric fluorescent probe
更新于2025-09-09 09:28:46
-
InGaAs-GaAs Nanowire Avalanche Photodiodes Toward Single Photon Detection in Free-Running Mode
摘要： Single photon detection at near-infrared (NIR) wavelengths is critical for light detection and ranging (LiDAR) systems used in imaging technologies such as autonomous vehicle trackers and atmospheric remote sensing. Portable, high-performance LiDAR relies on silicon-based single-photon avalanche diodes (SPADs) due to their extremely low dark count rate (DCR) and afterpulsing probability, but their operation wavelengths are typically limited up to 905 nm. Although InGaAs-InP SPADs offer an alternative platform to extend the operation wavelengths to eye-safe ranges, their high DCR and afterpulsing severely limit their commercial applications. Here we propose a new selective absorption and multiplication avalanche photodiode (SAM-APD) platform composed of vertical InGaAs-GaAs nanowire arrays for single photon detection. Among a total of 4400 nanowires constituting one photodiode, each avalanche event is confined in a single nanowire, which means that the avalanche volume and the number of filled traps can be drastically reduced in our approach. This leads to an extremely small afterpulsing probability compared with conventional InGaAs-based SPADs and enables operation in free-running mode. We show DCR below 10 Hz, due to reduced fill factor, with photon count rates of 7.8 MHz and timing jitter less than 113 ps, which suggest that nanowire-based NIR focal plane arrays for single photon detection can be designed without active quenching circuitry that severely restricts pixel density and portability in NIR commercial SPADs. Therefore, the proposed work based on vertical nanowires provides a new degree of freedom in designing avalanche photodetectors and could be a stepping stone for high-performance InGaAs SPADs.
关键词： free-running mode,InGaAs-GaAs,single photon detection,avalanche photodiodes,near-infrared,nanowires
更新于2025-09-09 09:28:46
-
Granular lesions of short-wavelength and near-infrared autofluorescence in diabetic macular oedema
摘要： Objectives To document and characterise hyper- and hypo-re?ective lesions, which we describe as ‘granular’ on short-wavelength auto?uorescence (SW-AF) and near-infrared (NIR)-AF images in diabetic macular oedema (DMO). Methods Consecutive 103 eyes of 78 patients suffering from centre-involving DMO were reviewed retrospectively. Mosaics of hyper- and hypo-?uorescent dots on both SW-AF and NIR-AF signals were delineated and de?ned as granular lesions in the macula. We evaluated the association of such lesions with the logarithm of the minimum angle of resolution visual acuity (logMAR VA) and spectral-domain optical coherence tomography (SD-OCT) images. Results Diffuse mosaics of hyper- and hypo-?uorescent dots were delineated in 36 and 45 eyes on SW-AF and NIR-AF images, respectively, and both AF images de?ned granular lesions in 33 eyes. These lesions were delineated in both the fovea and extrafoveal areas on NIR-AF images but were limited to the parafoveal and perifoveal sub?elds on SW-AF images. There was a signi?cant difference in logMAR VA between eyes with and without granular lesions (0.358 ± 0.269 vs. 0.185 ± 0.234; P = 0.001). Granular lesions were associated with the mosaic pattern on NIR-AF images (P < 0.001) but not with other parameters on SW-AF and NIR-AF images. The retinal thickness in the central sub?eld was greater in eyes with granular lesions (538.0 ± 163.6 μm vs. 448.8 ± 120.2 μm; P = 0.003). Granular lesions were associated with ELM disruption and hyper-re?ective foci in the outer retinal layers (P = 0.004 and P = 0.037, respectively). Conclusions Granular lesions de?ned on both SW-AF and NIR-AF images were related to retinal oedema with photoreceptor damage and concomitant VA reduction in DMO.
关键词： diabetic macular oedema,photoreceptor damage,near-infrared auto?uorescence,granular lesions,short-wavelength auto?uorescence
更新于2025-09-09 09:28:46
-
Ray-tracing 3D dust radiative transfer with DART-Ray: code upgrade and public release
摘要： We present an extensively updated version of the purely ray-tracing 3D dust radiation transfer code DART-Ray. The new version includes five major upgrades: 1) a series of optimizations for the ray-angular density and the scattered radiation source function; 2) the implementation of several data and task parallelizations using hybrid MPI+OpenMP schemes; 3) the inclusion of dust self-heating; 4) the ability to produce surface brightness maps for observers within the models in HEALPix format; 5) the possibility to set the expected numerical accuracy already at the start of the calculation. We tested the updated code with benchmark models where the dust self-heating is not negligible. Furthermore, we performed a study of the extent of the source influence volumes, using galaxy models, which are critical in determining the efficiency of the DART-Ray algorithm. The new code is publicly available, documented for both users and developers, and accompanied by several programmes to create input grids for different model geometries and to import the results of N-body and SPH simulations. These programmes can be easily adapted to different input geometries, and for different dust models or stellar emission libraries.
关键词： scattering,dust, extinction,radiative transfer,infrared: ISM,methods: numerical
更新于2025-09-09 09:28:46
-
Towards a new image processing system at Wendelstein 7-X: From spatial calibration to characterization of thermal events
摘要： Wendelstein 7-X (W7-X) is the most advanced fusion experiment in the stellarator line and is aimed at proving that the stellarator concept is suitable for a fusion reactor. One of the most important issues for fusion reactors is the monitoring of plasma facing components when exposed to very high heat loads, through the use of visible and infrared (IR) cameras. In this paper, a new image processing system for the analysis of the strike lines on the inboard limiters from the first W7-X experimental campaign is presented. This system builds a model of the IR cameras through the use of spatial calibration techniques, helping to characterize the strike lines by using the information given by real spatial coordinates of each pixel. The characterization of the strike lines is made in terms of position, size, and shape, after projecting the camera image in a 2D grid which tries to preserve the curvilinear surface distances between points. The description of the strike-line shape is made by means of the Fourier Descriptors.
关键词： fusion reactor,infrared cameras,Fourier Descriptors,stellarator,Wendelstein 7-X,strike lines,image processing,spatial calibration
更新于2025-09-09 09:28:46
-
Stark effect or coverage dependence? Disentangling the EC-SEIRAS vibrational shift of sulfate on Au(111)
摘要： Infrared spectroscopy is a widely employed analytical tool in (electrochemical) surface science as the spectra contain a wealth of information about the interaction of interfacial adsorbates with their environment. Separating and quantifying individual contributions, for example, of co-adsorbates, the substrate or electric field effects, on the overall spectral response, however, is often non-trivial as the various interactions manifest themselves in similar spectral behavior. Here, we present an experimental approach to differentiate between and quantify potential-induced coverage dependence and field-related Stark effects observed in a sulfate band shift of 93.5 ± 1.5 cm?1/V in electrochemical infrared spectra of the showcase sulfate/Au(111) interface. In combination with a simple linear model equation used to describe the potential-induced peak shift of the sulfate stretch vibration, we determine the coverage dependence contribution to be 15.6 ± 1.2 cm?1/θSO and the Stark effect to amount to 75.6 ± 2.7 cm?1/V. Our work provides a novel route to gain fundamental insight into interfacial adsorbate interactions in electrochemical surface science.
关键词： Stark effect,Infrared spectroscopy,sulfate/Au(111) interface,electrochemical surface science,coverage dependence
更新于2025-09-09 09:28:46