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- 2019
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- infrared image
- target detection
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- target detection
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- 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
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Efficient improvement of 2.7μm luminescence of Er3+:oxyfluorideglass containing gallium by Yb3+ions codoping
摘要： Mid-infrared laser materials with low phonon energy have significant applications. However, the development of available glass systems for high-power laser gain medium have posed a great challenge. Therefore, we investigated the 2.7 μm spectroscopic properties of Er3+/Yb3+-codopedoxyfluoride glass containing gallium, which were prepared by typically melting and quenching methods. The 2.7 μm luminescence properties of the Er3+/Yb3+-codopedoxyfluoride glass containing gallium were recorded by a 980 nm laser diode. The Judd–Ofelt parameters, decay curves, emission cross section, energy transfer efficiency, and quantum efficiency were calculated. The maximum emission cross section of YbFGa-0.5 is 1.63×10?20 cm2 by 980 nm excitation. The energy transfer efficiency is calculated to be 77.8% for the YbFGa-0.5 glass around 2700 nm. The quantum efficiency at 1530 nm is 65.6%. The resulting reveals that the best doping concentration ratio of Er3+:Yb3+ ions is 1:0.5, and suggests an effective energy transfer from Yb3+ to Er3+ ions.
关键词： optical materials,rare-earth ions doped,optical spectroscopy,mid-infrared,energy transfer
更新于2025-09-09 09:28:46
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Recent Advances on Nitrofluorene Derivatives: Versatile Electron Acceptors to Create Dyes Absorbing from the Visible to the Near and Far Infrared Region
摘要： Push–pull dyes absorbing in the visible range have been extensively studied so that a variety of structures have already been synthesized and reported in the literature. Conversely, dyes absorbing in the near and far infrared region are more scarce and this particularity relies on the following points: difficulty of purification, presence of side-reaction during synthesis, low availability of starting materials, and low reaction yields. Over the years, several strategies such as the elongation of the π-conjugated spacer or the improvement of the electron-donating and accepting ability of both donors and acceptors connected via a conjugated or an aliphatic spacer have been examined to red-shift the absorption spectra of well-established visible dyes. However, this strategy is not sufficient, and the shift often remains limited. A promising alternative consists in identifying a molecule further used as an electron-accepting group and already presenting an absorption band in the near infrared region and to capitalize on its absorption to design near and far infrared absorbing dyes. This is the case with poly(nitro)fluorenes that already exhibit such a contribution in the near infrared region. In this review, an overview of the different dyes elaborated with poly(nitro)fluorenes is presented. The different applications where these different dyes have been used are also detailed.
关键词： Knoevenagel reaction,near infrared absorption,fluorene,poly(nitro)fluorene,push–pull chromophore,nitrofluorene
更新于2025-09-09 09:28:46
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Direct Determination of Ni2+-Capacity of IMAC Materials Using Near-Infrared Spectroscopy
摘要： The present paper reports a new method for the quanti?cation of the Ni2+-capacity of an immobilized metal af?nity chromatography (IMAC) material using near-infrared spectroscopy (NIRS). Conventional analyses using UV absorption spectroscopy or atomic absorption spectrometry (AAS) need to dissolve the silica-based metal chelate sorbent as sample pretreatment. In the ?rst step, those methods were validated on the basis of an ideal homogenous NiSO4-solution and unveiled that UV with an intermediate precision of 2.6% relative standard deviation (RSD) had an advantage over AAS with an intermediate precision of 6.5% RSD. Therefore, UV analysis was chosen as reference method for the newly established NIRS model which has the advantage of being able to measure the material directly in diffuse re?ection mode. Partial least squares regression (PLSR) analysis was used as multivariate data analysis tool for quanti?cation. The best PLSR result obtained was: coef?cient of determination (R2) = 0.88, factor = 2, root mean square error of prediction (RMSEP) = 22 μmol/g (test-set validation) or 7.5% RSDPLSR. Validation of the Ni2+-capacity using UV absorption spectroscopy resulted in an intermediate precision of ±18 μmol/g or 5.0% RSD. Therefore, NIRS provides a fast alternative analysis method without the need of sample preparation.
关键词： Ni2+-capacity,partial least squares regression,IMAC,near-infrared spectroscopy,method validation
更新于2025-09-09 09:28:46
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Study of memory deficit in Alzheimer’s disease by means of complexity analysis of fNIRS signal
摘要： Working memory deficit is a signature of Alzheimer’s disease (AD). The free and cued selective reminding test (FCSRT) is a clinical test that quantifies memory deficit for AD diagnosis. However, the diagnostic accuracy of FCSRT may be increased by accompanying it with neuroimaging. Since the test requires doctor–patient interaction, brain monitoring is challenging. Functional near-infrared spectroscopy (fNIRS) could be suited for such a purpose because of the fNIRS flexibility. We investigated whether the complexity, based on sample entropy and multiscale entropy metrics, of the fNIRS signal during FCSRT was correlated with memory deficit in early AD. fNIRS signals were recorded over the prefrontal cortex of healthy and early AD participants. Group differences were tested through Wilcoxon–Mann–Whitney test (p < 0.05). At group level, we found significant differences for Brodmann areas 9 and 46. The results, although preliminary, demonstrate the feasibility of performing ecological studies on early AD with fNIRS. This approach may provide a potential neuroimaging-based method for diagnosis of early AD, viable at the doctor’s office level, improving test-based diagnosis. The increased entropy of the fNIRS signal in early AD suggests the opportunity for further research on the neurophysiological status in AD and its relevance for clinical symptoms.
关键词： entropy,functional near-infrared spectroscopy,Alzheimer’s disease,free and cued selective reminding test
更新于2025-09-09 09:28:46
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Highly Efficient Near-Infrared Photothermal Conversion of a Single Carbon Nanocoil Indicated by Cell Ejection
摘要： Carbon nanocoil (CNC), which has excellent properties of near-infrared (NIR) absorption and photo-electrical response, is considered as a potential NIR sensing and bioengineering material. In this work, a high-speed living cell ejection is realized in a yeast cell solution based on the photothermal conversion induced by a NIR laser irradiation on the surface of a CNC. The cell ejection reveals a thermal convection of solution induced by the laser irradiated CNC and can be used to evaluate the photothermal conversion ability of CNC. The dynamic behavior of the thermal convection behind cell ejection is studied experimentally and analytically. It is found that the initial solution flow velocity of the dynamic process reaches more than 103 μm/s. Approximately, 60% of the laser energy illuminated on the CNC is converted into thermal energy. The unique helical morphology of CNC enables its high NIR photothermal conversion efficiency. The average convective heat transfer coefficient on the contact area between CNC and surrounding water is deduced to be as high as 7.0 × 105 W/(m2·K). These results indicate that CNC has promising potential applications on microfluidics, laser-operated flow cytometers, bioparticle ejection, and micro-/nano-laser-operated heat generators and exchangers.
关键词： Cell ejection,Thermal convection,Carbon nanocoil,Photothermal conversion,Near-infrared
更新于2025-09-09 09:28:46
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Alkaline Phosphatase-Triggered Self-Assembly of Near-Infrared Nanoparticles for Enhanced Photoacoustic Imaging of Tumor
摘要： Photoacoustic (PA) imaging is advantageous for the diagnosis of superficial cancer with high spatial resolution. However, to the best of our knowledge, using an alkaline phosphatase (ALP)-activatable probe for enhanced PA imaging of tumor has not been reported. In this work, we rationally designed a NIR probe IR775-Phe-Phe-Tyr(H2PO3)-OH (1P) for PA imaging ALP activity in vitro and in tumor. Under the catalysis of ALP, 1P was efficiently converted to IR775-Phe-Phe-Tyr-OH (1) which self-assembled into the nanoparticles 1-NPs. Formation of 1-NPs induced a 6.4-fold enhancement of the 795 nm PA signal of 1P. In vivo tumor PA imaging results indicated that, compared with that in the ALP inhibitor-treated control group, PA contrast in the experimental group enhanced 2.3 folds at 4 h post 1P injection. By replacing the Phe-Phe-Tyr(H2PO3)-OH motif in 1P with other enzyme-cleavable ones, we hope more PA probes could be developed for the precise diagnoses of their corresponding cancers in the near future.
关键词： photoacoustic imaging,near-infrared nanoparticle,alkaline phosphatase,self-assembly
更新于2025-09-09 09:28:46
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A Novel Method for Classifying Driver Mental Workload Under Naturalistic Conditions With Information From Near-Infrared Spectroscopy
摘要： Driver cognitive distraction is a critical factor in road safety, and its evaluation, especially under real conditions, presents challenges to researchers and engineers. In this study, we considered mental workload from a secondary task as a potential source of cognitive distraction and aimed to estimate the increased cognitive load on the driver with a four-channel near-infrared spectroscopy (NIRS) device by introducing a machine-learning method for hemodynamic data. To produce added cognitive workload in a driver beyond just driving, two levels of an auditory presentation n-back task were used. A total of 60 experimental data sets from the NIRS device during two driving tasks were obtained and analyzed by machine-learning algorithms. We used two techniques to prevent overfitting of the classification models: (1) k-fold cross-validation and principal-component analysis, and (2) retaining 25% of the data (testing data) for testing of the model after classification. Six types of classifier were trained and tested: decision tree, discriminant analysis, logistic regression, the support vector machine, the nearest neighbor classifier, and the ensemble classifier. Cognitive workload levels were well classified from the NIRS data in the cases of subject-dependent classification (the accuracy of classification increased from 81.30 to 95.40%, and the accuracy of prediction of the testing data was 82.18 to 96.08%), subject-independent classification (the accuracy of classification increased from 84.90 to 89.50%, and the accuracy of prediction of the testing data increased from 84.08 to 89.91%), and channel-independent classification (classification 82.90%, prediction 82.74%). NIRS data in conjunction with an artificial intelligence method can therefore be used to classify mental workload as a source of potential cognitive distraction in real time under naturalistic conditions; this information may be utilized in driver assistance systems to prevent road accidents.
关键词： mental workload,near-infrared spectroscopy,artificial intelligence,driver attention,cognitive distraction,classification
更新于2025-09-09 09:28:46
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Infrared Investigations of the Neutral-Ionic Phase Transition in TTF-CA and Its Dynamics
摘要： The neutral-ionic phase transition in TTF-CA was investigated by steady-state and time-resolved infrared spectroscopy. We describe the growth of high-quality single crystals and their characterization. Extended theoretical calculations were performed in order to obtain the band structure, the molecular vibrational modes and the optical spectra along all crystallographic axes. The theoretical results are compared to polarization-dependent infrared reflection experiments. The temperature-dependent optical conductivity is discussed in detail. We study the photo-induced phase transition in the vicinity of thermally-induced neutral-ionic transition. The observed temporal dynamics of the photo-induced states is attributed to the random-walk of neutral-ionic domain walls. We simulate the random-walk annihilation process of domain walls on a one-dimensional chain.
关键词： domain-wall motion,neutral-ionic phase transition,steady-state and transient infrared spectroscopy,TTF-CA,charge-transfer salts,characterization,random-walk simulations,light-induced phase transition,vibrational spectroscopy,crystal growth
更新于2025-09-09 09:28:46
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Radiometric consistency assessment of hyperspectral infrared sounders
摘要： The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark data sets for both intercalibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and MetOp-B at the ?nest spectral scale and with AIRS on Aqua in 25 selected spectral regions through simultaneous nadir overpass (SNO) observations in 2013, to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the long-wave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1–0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both polar and tropical SNOs. The combined global SNO data sets indicate that the CrIS–AIRS BT differences are less than or around 0.1 K among 21 of 25 spectral regions and they range from 0.15 to 0.21 K in the remaining four spectral regions. CrIS–AIRS BT differences in some comparison spectral regions show weak scene-dependent features.
关键词： hyperspectral infrared sounders,SNO observations,CrIS,radiometric consistency,IASI,brightness temperature differences,AIRS
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Communication and Signal Processing (ICCSP) - Chennai, India (2018.4.3-2018.4.5)] 2018 International Conference on Communication and Signal Processing (ICCSP) - Statistical Analysis of Surface Temperature Distribution Pattern in Plantar Foot of Healthy and Diabetic Subjects Using Thermography
摘要： Diabetic foot complications are a major cause of concern for diabetic patients as it affects mobility and quality of life. Any computer aided diagnosis system would be very useful in the early detection and hence treatment and cure. For such a system, the surface temperature distribution patterns in the plantar region of the foot of both healthy and diabetic subjects have to be analyzed to detect any abnormality. In this paper we have analyzed the infrared thermal images of 62 diabetic and 20 healthy subjects to identify the temperature distribution patterns capable of detecting diabetic foot complications. The images were taken using Fluke TiX560 thermal imager. Image processing and analysis was done in MATLAB.
关键词： Infrared Thermography,Statistical Analysis,Mean Temperature Difference,Surface temperature distribution,Diabetic Foot Complications,Correlation
更新于2025-09-09 09:28:46