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oe1(光电查) - 科学论文

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出版时间
  • 2018
  • 2015
研究主题
  • classification
  • Fruit defects
  • Jujube
  • Principal component analysis
  • Hyperspectral imaging
  • Xanthomonas oryzae
  • multispectral and multimodal microscopy
  • spectroscopic imaging
  • plant cell diseases
  • rice
应用领域
  • Optoelectronic Information Science and Engineering
  • Applied Physics
  • Measurement and Control Technology and Instruments
机构单位
  • 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
606 条数据
?? 中文（中国） ▾

  • Multispectral Management of the Photon Orbital Angular Momentum

    摘要： We report on a programmable liquid crystal spatial light modulator enabling independent orbital angular momentum state control on multiple spectral channels. This is done by using electrically controllable “topological pixels" that independently behave as geometric phase micro-optical elements relying on self-engineered liquid crystal defects. These results open interesting opportunities in optical manipulation, sensing, imaging, and communications, as well as information processing. In particular, spectral vortex modulation allows considering singular spatiotemporal shaping of ultrashort pulses which may find applications in many areas such as material processing, spectroscopy, or elementary particles acceleration.

    关键词： liquid crystal spatial light modulator,spectral vortex modulation,photon orbital angular momentum,geometric phase micro-optical elements,ultrashort pulses

    更新于2025-09-23 15:21:01

  • [ACM Press the 4th International Conference - Hong Kong, Hong Kong (2018.02.24-2018.02.26)] Proceedings of the 4th International Conference on Virtual Reality - ICVR 2018 - Research on Application of Multiple Optical Pattern Recognition Model in Power Equipment

    摘要： This paper is mainly research on the power equipment of visible light spectrum recognition model. The main contents of the research include constructing experimental evaluation of image acquisition standard operating system, establishing multi-spectral sample library for power equipment, studying HDFS mode based image data storage and management technology, constructing spectral testing technology data centre service framework for power equipment, typical equipment image recognition and analysis algorithm for power network, etc. Through the study of these technologies, we aim to achieve the identification of electrical equipment.

    关键词： Multi-spectral detection,algorithm technology,Identification analysis

    更新于2025-09-23 15:21:01

  • P-OMP-IR ALGORITHM FOR HYBRID PRECODING IN MILLIMETER WAVE MIMO SYSTEMS

    摘要： This paper presents a P-OMP-IR algorithm for the hybrid precoding problem in millimeter wave (mm-Wave) multiple-input multiple-output (MIMO) systems. In the proposed approach, the digital precoding matrix is updated via the orthogonal matching pursuit (OMP) method, and the analog precoding matrix is re?ned column by column using the dominant singular value and corresponding singular vectors of a residual matrix successively. During the re?ning phase of the analog precoding matrix, an extended power method is designed to calculate the dominant singular value and the corresponding left and right singular vectors, which is able to reduce the computational complexity signi?cantly. Simulation results show that the proposed algorithm can not only reduce the residual of the hybrid precoder e?ectively, but also improve the spectral e?ciency consistently.

    关键词： millimeter wave,MIMO systems,orthogonal matching pursuit,P-OMP-IR algorithm,spectral efficiency,hybrid precoding

    更新于2025-09-23 15:21:01

  • Side chain torsion dictates planarity and ionizability of Green fluorescent protein’s chromophore leading to spectral perturbations.

    摘要： Spectral characteristics of Fluorescent Proteins (FP) are well studied and through protein engineering, several FP variants constituting entire visible spectrum have been created. One of the most common mechanisms attributed to spectral shifts in FP are excited state proton transfer (ESPT), hydroxyl moiety protonation and deprotonation, along with chromophore Cis-Trans isomerism. Most widely studied FPs are those derived from avGFP (Aequorea victoria GFP) and Dsred (Discosoma coral). Apart from the above mechanism, certain interacting residues are said to play a vital role in altering the proton transfer pathway shift. The torsional changes of wild avGFP, S65T avGFP, and Dsred has been studied to van der Waals packing in Dsred is more compact than that of avGFP, thus creating a low solvent occupiable environment and reduced solvent interactions having higher red spectral hypothesize the torsional landscape and altered residual interactions are prominent factors for the spectral shifts. Through our 200 ns molecular dynamics investigation we prospect that leading to numerous spectral variants. Similarly, the hydrogen-bonded networks solely cannot dictate the energy landscape of FPs. Non-bonded interactions also can create secondary harmonic shifts by dipole-dipole inductions. Side chain contacts tend to alter the topological and torsional geometry, thereby disturbing the chromophore’s planarity. Side chain torsional variations have almost been unaccounted for their distortions in FP’s. We comprehend the inter-residual contact distance and the geometrical descriptors.

    关键词： Green fluorescent protein,spectral perturbations,Sidechain torsional variations,Residual accessible area,Chromophore planarity

    更新于2025-09-23 15:21:01

  • Increase of an Output Optical Signal of an Acousto-Optic Monochromator upon Frequency Modulation of a Control Signal

    摘要： An angular aperture of an acousto-optical filter upon a linear frequency-modulated (chirp) control signal has been experimentally studied for the first time. The results of studying the spectral and angular dependences of the spectral transmission function of a filter upon a frequency modulation have shown the possibility of an efficient increase of the output optical signal. The value of the optical signal was increased by 2000 times using the selected design of the acousto-optical filter. This makes it possible to obtain a gain in the measurement time or in the value of the detected optical signal. Such an increase of the output signal upon a chirp control signal is provided by the increase of the angular aperture and broadening of the spectral transmission bandwidth together with the required proportional increase of the control signal power.

    关键词： angular aperture,output optical signal,spectral transmission function,acousto-optical filter,frequency modulation

    更新于2025-09-23 15:21:01

  • Ultrastrong-coupling regime of nondipolar light-matter interactions

    摘要： We present a circuit-QED scheme which makes it possible to reach the ultrastrong-coupling regime of a nondipolar interaction between a single qubit and a quantum resonator. We show that the system Hamiltonian is well approximated by a two-photon quantum Rabi model and propose a simple scattering experiment to probe its fundamental properties. In particular, we identify a driving scheme that reveals the change in selection rules characterizing the breakdown of the rotating-wave approximation and the transition from strong to ultrastrong two-photon interactions. Finally, we show that a frequency crowding in a narrow spectral region is observable in the output fluorescence spectrum as the coupling strength approaches the collapse point, paving the way to the direct observation of the onset of the spectral collapse in a solid-state device.

    关键词： nondipolar light-matter interactions,spectral collapse,two-photon quantum Rabi model,ultrastrong-coupling regime,circuit-QED

    更新于2025-09-23 15:21:01

  • Spectral Image Fusion from Compressive Measurements

    摘要： Compressive spectral imagers reduce the number of sampled pixels by coding and combining the spectral information. However, sampling compressed information with simultaneous high spatial and high spectral resolution demands expensive high-resolution sensors. This work introduces a model allowing data from high spatial/low spectral and low spatial/high spectral resolution compressive sensors to be fused. Based on this model, the compressive fusion process is formulated as an inverse problem that minimizes an objective function defined as the sum of a quadratic data fidelity term and smoothness and sparsity regularization penalties. The parameters of the different sensors are optimized and the choice of an appropriate regularization is studied in order to improve the quality of the high resolution reconstructed images. Simulation results conducted on synthetic and real data, with different CS imagers, allow the quality of the proposed fusion method to be appreciated.

    关键词： Spectral imaging,data fusion,remote sensing,compressive sampling

    更新于2025-09-23 15:21:01

  • Multi-Algorithm Indices and Look-Up Table for Chlorophyll-a Retrieval in Highly Turbid Water Bodies Using Multispectral Data

    摘要： Many approaches have been proposed for monitoring the eutrophication of Case 2 waters using remote sensing data. Semi-analytical algorithms and spectrum matching are two major approaches for chlorophyll-a (Chla) retrieval. Semi-analytical algorithms provide indices correlated with phytoplankton characteristics, (e.g., maximum and minimum absorption peaks). Algorithms’ indices are correlated with measured Chla through the regression process. The main drawback of the semi-analytical algorithms is that the derived relation is location and data limited. Spectrum matching and the look-up table approach rely on matching the measured re?ectance with a large library of simulated references corresponding to wide ranges of water properties. The spectral matching approach taking hyperspectral measured re?ectance as an input, leading to dif?culties in incorporating data from multispectral satellites. Consequently, multi-algorithm indices and the look-up table (MAIN-LUT) technique is proposed to combine the merits of semi-analytical algorithms and look-up table, which can be applied to multispectral data. Eight combinations of four algorithms (i.e., 2-band, 3-band, maximum chlorophyll index, and normalized difference chlorophyll index) are investigated for the MAIN-LUT technique. In situ measurements and Medium Resolution Imaging Spectrometer (MERIS) sensor data are used to validate MAIN-LUT. In general, the MAIN-LUT provide a comparable retrieval accuracy with locally tuned algorithms. The most accurate of the locally tuned algorithms varied among datasets, revealing the limitation of these algorithms to be applied universally. In contrast, the MAIN-LUT provided relatively high retrieval accuracy for Tokyo Bay (R2 = 0.692, root mean square error (RMSE) = 21.4 mg m?3), Lake Kasumigaura (R2 = 0.866, RMSE = 11.3 mg m?3), and MERIS data over Lake Kasumigaura (R2 = 0.57, RMSE = 36.5 mg m?3). The simulated reflectance library of MAIN-LUT was generated based on inherent optical properties of Tokyo Bay; however, the MAIN-LUT also provided high retrieval accuracy for Lake Kasumigaura. MAIN-LUT could capture the spatial and temporal distribution of Chla concentration for Lake Kasumigaura.

    关键词： Red-NIR algorithm,spectral matching,look-up table,Case 2 waters,bio-optical model,inland lakes,MERIS

    更新于2025-09-23 15:21:01

  • Influence of Axial Length on Thickness Measurements Using Spectral-Domain Optical Coherence Tomography

    摘要： The purpose of this study was to assess the in?uence of axial length on spectral-domain optical coherence tomography (SD-OCT) thickness measurements in patients with subretinal visual implants. Data from eight emmetropic pseudophakic eyes of eight patients with subretinal visual implants were analyzed retrospectively. These patients participated in the monocentric part of a multicenter trial. The axial length was measured in three short (<22.5 mm), three medium (22.51–25.50 mm), and two long (>25.52 mm) eyes. Using Heidelberg Spectralis, the known thickness of a subretinal implant microchip (70 lm) was measured on 15 images per eye with SD-OCT, using the software calipers. The mean axial length was 20.8 6 0.8 mm in short eyes, 23.3 6 0.4 mm in medium eyes, and 26.3 6 0.5 mm in long eyes. We found in short eyes, in medium eyes, and in long eyes a mean value of microchip thickness measurements from SD-OCT of 82.9 6 1.4 lm, 70.5 6 1.3 lm, and 64.2 6 1.3 lm, respectively. The thickness measurements decreased in SD-OCT measurements with longer axial lengths signi?cantly (P < 0.0001). Axial length in?uences SD-OCT thickness measurements. Our ?ndings demonstrate accuracy of the scaling in SD-OCT thickness measurements in emmetropic medium eyes. Caution is recommended when comparing the measured values of short and long eyes with the normative database of the instrument. There is a need for larger sample-size studies to con?rm our results.

    关键词： subretinal visual implant,spectral-domain optical coherence tomography (SD-OCT),axial length,Heidelberg Spectralis,in vivo measurement

    更新于2025-09-23 15:21:01

  • Optical coherence tomography parameters predictive of visual outcome after anti-VEGF therapy for retinal vein occlusion

    摘要： Purpose: To determine the optical coherence tomography (OCT) parameters that are predictive of visual outcome after anti-VEGF therapy for a retinal vein occlusion (RVO). Methods: Fifty-seven eyes with macular edema (ME) secondary to a central or branch RVO treated with bevacizumab or ranibizumab were studied. Spectral-domain OCT and microperimetry were performed before, 1, 3, and 6 months after the treatment and at the final visit. Central retinal thickness (CRT), macular volume (MV), integrity of the external limiting membrane (ELM), ellipsoid zone (EZ), and foveal bulge (FB), and photoreceptor outer segment (PROS) length were determined. Results: The mean follow-up period was 17.8±11.5 months. In 46 of the 57 eyes, a resolution of the ME was achieved. The pretreatment CRT and MV, presence of intact ELM, EZ, and FB, and PROS length at the time of ME resolution were significantly correlated with the best-corrected visual acuity and retinal sensitivity at the final visit (P0.050). Multiple regression analyses showed that the pretreatment MV had the highest correlation with the posttreatment best-corrected visual acuity and retinal sensitivity (P0.050). Conclusion: The CRT, MV, ELM, EZ, FB, and PROS length are predictive factors for the visual outcome after anti-VEGF therapy for RVO.

    关键词： spectral-domain optical coherence tomography,visual acuity,retinal sensitivity,anti-VEGF therapy,retinal vein occlusion

    更新于2025-09-23 15:21:01