- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2018
- 2015
- classification
- Fruit defects
- Jujube
- Principal component analysis
- Hyperspectral imaging
- Xanthomonas oryzae
- multispectral and multimodal microscopy
- spectroscopic imaging
- plant cell diseases
- rice
- Optoelectronic Information Science and Engineering
- Applied Physics
- Measurement and Control Technology and Instruments
- Brno University of Technology
- University of Sciences, Technique and Technology Bamako
- Mohammed V University in Rabat
- Southern Taiwan University of Science and Technology
- Institut National Polytechnique Felix Houphou?t-Boigny Yamoussoukro
-
Spectral Imaging Technology - A Review on Skin and Endoscopy Applications
摘要： Spectral imaging technology is an emerging modality that combines the advantages of both imaging and spectroscopy (high spatial and spectral resolution) in one device. The technology has potential in numerous medical imaging and diagnostic applications. In this review, we describe the techniques used to acquire spectral images and the methods used for analyzing spectral images. We then provide detailed review about the progress of the spectral imaging technology in skin and endoscopy applications. This review also covers the recent patents on spectral imaging devices, methods, and data analysis algorithms.
关键词： optical scattering,spectroscopy,Endoscopy,spectral imaging,tissue reflectance,skin diagnosis,medical diagnosis,optical absorption
更新于2025-09-10 09:29:36
-
METASURFACE SYNTHESIS FOR TIME-HARMONIC WAVES: EXACT SPECTRAL AND SPATIAL METHODS (Invited Paper)
摘要： Two exact approaches to synthesize metasurfaces for time-harmonic waves are discussed. The first approach is a spectral approach based on wave momentum conservation. Here, the spectral approach is applied to scalar and paraxial wave transformations. This approach effectively allows the arbitrary translation of the transformation plane parallel to the metasurface. The second approach is a direct-space approach based on the extraction of the susceptibility tensors of the metasurface elements. This approach is applied to vectorial field transformation and can be used for single or multiple transformations. An example of wave transformation by a metasurface is illustrated for each of the two approaches.
关键词： susceptibility tensors,metasurface synthesis,wave momentum conservation,time-harmonic waves,spatial approach,spectral approach
更新于2025-09-10 09:29:36
-
SCATTERING AND TRANSMISSION OF WAVES IN MULTIPLE RANDOM ROUGH SURFACES: ENERGY CONSERVATION STUDIES WITH THE SECOND ORDER SMALL PERTURBATION METHOD
摘要： Energy conservation is an important consideration in wave scattering and transmission from random rough surfaces and is particularly important in passive microwave remote sensing. In this paper, we study energy conservation in scattering from layered random rough surfaces using the second order small perturbation method (SPM2). SPM2 includes both first order incoherent scattering and a second order correction to the coherent fields. They are combined to compute the total reflected and transmitted powers, as a sum of integrations over wavenumber kx, in which each integration includes the surface power spectra of a rough interface weighted by an emission kernel function (assuming the roughness of each interface is uncorrelated). We calculate the corresponding kernel functions which are the power spectral densities for one-dimensional (1D) surfaces in 2D scattering problems and examine numerical results for the cases of 2 rough interfaces and 51 rough interfaces. Because it is known that the SPM when evaluated to second order conserves energy, and it can be applied to second order for arbitrary surface power spectra, energy conservation can be shown to be satisfied for each value of kx in the kernel functions. The numerical examples show that energy conservation is obeyed for any dielectric contrast, any layer configuration and interface, and arbitrary roughness spectra. The values of reflected or transmitted powers predicted, however, are accurate only to second order in small surface roughness.
关键词： roughness spectra,wave scattering,random rough surfaces,SPM2,transmission,passive microwave remote sensing,layered random rough surfaces,small perturbation method,power spectral densities,Energy conservation,dielectric contrast
更新于2025-09-10 09:29:36
-
On crack propagation monitoring by using reflection spectra of AFBG and UFBG sensors
摘要： Due to their light weight, small size and immunity to electromagnetic interference, Fiber Bragg Gratings (FBG) have shown great potential in structural health monitoring (SHM) area. Ordinarily, FBGs are used as the quasi-distributed sensors to detect structural damage by central wavelengths shifting, which has robust problem in real engineering application. It is found that the FBG reflection spectra can also be distorted with the non-uniform strain field caused by crack. Multiple indices can be extracted from the reflection spectra which can provides more information on the crack propagation. However, till now no researches have been investigated regarding the behaviors of different kinds of FBGs for crack propagation monitoring based on the FBG reflection spectra. In this paper, behaviors of the apodized FBG (AFBG) and the uniform FBG (UFBG) sensors for structural crack propagation monitoring are investigated. The reflective spectral behaviors of both UFBG and AFBG sensors under crack-generated non-uniform strain are illustrated by simulation and experiment. Three spectra indices, namely the central wavelength shift, the ratio of side lobe to main lobe and the information entropy, are proposed to indicate the propagation of the crack. The results show the UFBG sensors have better performance than the AFBG sensors which are more suitable for crack propagation monitoring.
关键词： crack propagation monitoring,uniform fiber Bragg gratings,apodized fiber Bragg gratings,structural health monitoring,spectral distortion
更新于2025-09-10 09:29:36
-
Low-Temperature Effect on the Electronic Structure and Spectral-Fluorescent Properties of Highly Dipolar Merocyanines
摘要： Absorption and fluorescence spectra of a vinylogous series of reversely solvatochromic merocyanines based on benzimidazole and malononitrile have been studied in frozen ethanol solutions at 77 K. It is found that they possess negative thermochromism – in contrast to both positively solvatochromic merocyanines and negatively solvatochromic symmetrical ionic polymethines – and even stronger negative thermofluorochromism. It has been deduced from the spectral data, that at low temperature their electronic structure becomes more dipolar, deviating substantially from the virtual ideal polymethine in both the ground and excited states. At that, owing probably to high polarity and ordering of frozen ethanol, the dipolarity of the studied merocyanines increases with the polymethine chain lengthening – the tendency not observed for them in common solvents. The conclusions, based on the spectra data analysis, have been verified by the (TD)DFT–PCM simulations of the dyes within the four-level scheme of electronic transitions.
关键词： Low-Temperature Effect,Spectral-Fluorescent Properties,Merocyanines,Quantum Chemistry,Electronic Structure,Molecular Structure,Spectroscopy
更新于2025-09-10 09:29:36
-
[Advances in Intelligent Systems and Computing] Intelligent Computing Volume 857 (Proceedings of the 2018 Computing Conference, Volume 2) || Automated Inner Limiting Membrane Segmentation in OCT Retinal Images for Glaucoma Detection
摘要： This paper proposes an automated algorithm to segment inner limiting membrane, i.e., the top most retinal layer in spectral domain optical coherence tomography (SD-OCT) scan. Its segmentation enables ophthalmologist to diagnose retinal diseases like macular edema and glaucoma as they affect ILM layer. The foremost purpose behind this segmentation is to correctly detect and diagnose glaucoma. Glaucoma is declared as the second common cause of blindness by World Health Organization, and can cause severe damage if not treated earlier. Optic-nerve-head (ONH) centered OCT scans are considered for glaucoma. Glaucoma can be described as cupping of optic nerve head, i.e. increase in the diameter of optic cup, and ends up in increasing cup to disc diameters (CDR) ratio. ILM is steeper in central-cup section in glaucoma images than normal images. Therefore, ILM is used to extract cup from macula or ONH centered OCT image volumes and then classify them further as glaucoma-tic or normal eye.
关键词： Cup to disc diameters (CDR),Spectral domain optical coherence tomography (SD-OCT),ILM,Segmentation,Glaucoma
更新于2025-09-10 09:29:36
-
The Analysis of Starlight (Two Centuries of Astronomical Spectroscopy) || The interpretation of stellar spectra and the birth of astrophysics
摘要： The interpretation of stellar spectra and the birth of astrophysics. At the end of the nineteenth century the two main branches of stellar spectroscopy were spectral classification and radial-velocity measurements. The latter department was still in its relative infancy, but classification, thanks mainly to the energy of Pickering at Harvard, was a major activity. Classification had become closely related to theories of stellar evolution and these two aspects could hardly be disentangled in, for example, the classification devised by Lockyer [1], which involved first rising and then falling temperatures of stars over their life cycles, and which had some theoretical support from the work of Jonathan Homer Lane (1819–80) and August Ritter on the gravitational collapse of gaseous spheres.
关键词： stellar evolution,spectral classification,stellar spectra,astrophysics,radial-velocity measurements
更新于2025-09-10 09:29:36
-
Spectral measurements of THz radiation emitted from intrinsic Josephson junction stacks
摘要： A superconducting integrated receiver (SIR) comprises all of the elements needed for heterodyne detection on a single chip. Recently, the SIR was successfully implemented for the first spectral measurements of terahertz (THz) radiation emitted from intrinsic Josephson junction stacks (BSCCO mesa) at frequencies up to 750 GHz; a linewidth below 10 MHz has been recorded in the high bias regime. In this report the results of the spectral measurements of THz radiation emitted from intrinsic Josephson junction stacks are summarized; recent results of spectrometric gas detection using THz radiation from a BSCCO mesa are presented.
关键词： BSCCO mesa,spectral measurements,heterodyne detection,intrinsic Josephson junction stacks,THz radiation
更新于2025-09-10 09:29:36
-
Phase control of plasmon enhanced two-photon photoluminescence in resonant gold nanoantennas
摘要： Plasmonic nanoantennas emit two-photon photoluminescence, which is much stronger than their second harmonic generation. Unfortunately, luminescence is an incoherent process and therefore generally not explored for nanoscale coherent control of the antenna response. Here, we demonstrate that, in resonant gold nanoantennas, the two-photon absorption process can be coherent, provided that the excitation pulse duration is shorter than the dephasing time of plasmon mode oscillation. Exploiting this coherent response, we show the pure spectral phase control of resonant gold nanoantennas, with effective read-out of the two-photon photoluminescence.
关键词： two-photon photoluminescence,gold nanoantennas,plasmonic nanoantennas,spectral phase control,coherent control
更新于2025-09-10 09:29:36
-
Fingerprinting electronic structure of heme iron by ab initio modeling of metal L-edge X-ray absorption spectra
摘要： The capability of the multiconfigurational restricted active space approach to identify electronic structure from spectral fingerprints is explored by applying it to iron L-edge X-ray absorption spectroscopy (XAS) of three heme systems that represent the limiting descriptions of iron in the Fe-O2 bond, ferrous and ferric [Fe(P)(ImH)2]0/1+ (P = porphine,ImH = imidazole), and FeII(P). The level of agreement between experimental and simulated spectral shapes is calculated using the cosine similarity, which gives a quantitative and unbiased assignment. Further dimensions in fingerprinting are obtained from the L-edge branching ratio, the integrated absorption intensity, and the edge position. The results show how accurate ab initio simulations of metal L-edge XAS can complement calculations of relative energies to identify unknown species in chemical reactions.
关键词： multiconfigurational restricted active space,branching ratio,integrated absorption intensity,iron L-edge X-ray absorption spectroscopy,electronic structure,cosine similarity,edge position,heme systems,spectral fingerprints
更新于2025-09-10 09:29:36