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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） ▾

  • Optically-Active Nanocrystals for Inner Filter Effect-Based Fluorescence Sensing: Achieving Better Spectral Overlap

    摘要： Among various photophysical processes for fluorescence modulation, inner filter effect (IFE) is well-known for its simplicity and no requirement of the distances between the fluorophores and the corresponding modulators. Theoretically, the key to maximize the sensitivity of IFE-based fluorescent assays is to enlarge the overlap between the absorption of the absorber and the excitation/emission of the fluorophores. However, it is difficult to achieve perfect spectral overlap for IFE in conventional organic fluorophores with constant excitation/emission. The emergence of various optically-active nanocrystals greatly revolutionize the IFE-based fluorescent sensing. Therefore in this critical review, we first made an introduction to IFE from the viewpoint of its photophysical process. Particularly, the similarities and differences of IFE and FRET for better understanding of IFE are discussed, and the general rules for verification of IFE are proposed. The use of various optically-active nanocrystals for enhanced IFE-based sensing is especially concerned in this review.

    关键词： fluorescence resonance energy transfer,Inner filter effect,spectral overlap,fluorescent sensors,optically-active nanocrystals,tunable spectra

    更新于2025-09-10 09:29:36

  • Spectral interferometry with waveform-dependent relativistic high-order harmonics from plasma surfaces

    摘要： The interaction of ultra-intense laser pulses with matter opened the way to generate the shortest light pulses available nowadays in the attosecond regime. Ionized solid surfaces, also called plasma mirrors, are promising tools to enhance the potential of attosecond sources in terms of photon energy, photon number and duration especially at relativistic laser intensities. Although the production of isolated attosecond pulses and the understanding of the underlying interactions represent a fundamental step towards the realization of such sources, these are challenging and have not yet been demonstrated. Here, we present laser-waveform-dependent high-order harmonic radiation in the extreme ultraviolet spectral range supporting well-isolated attosecond pulses, and utilize spectral interferometry to understand its relativistic generation mechanism. This unique interpretation of the measured spectra provides access to unrevealed temporal and spatial properties such as spectral phase difference between attosecond pulses and field-driven plasma surface motion during the process.

    关键词： ultra-intense laser pulses,spectral interferometry,attosecond regime,plasma mirrors,high-order harmonic radiation

    更新于2025-09-10 09:29:36

  • Digital Domain Power Division Multiplexed Dual Polarization Coherent Optical OFDM Transmission

    摘要： Capacity is the eternal pursuit for communication systems due to the overwhelming demand of bandwidth hungry applications. As the backbone infrastructure of modern communication networks, the optical fiber transmission system undergoes a significant capacity growth over decades by exploiting available physical dimensions (time, frequency, quadrature, polarization and space) of the optical carrier for multiplexing. For each dimension, stringent orthogonality must be guaranteed for perfect separation of independent multiplexed signals. To catch up with the ever-increasing capacity requirement, it is therefore interesting and important to develop new multiplexing methodologies relaxing the orthogonal constraint thus achieving better spectral efficiency and more flexibility of frequency reuse. Inspired by the idea of non-orthogonal multiple access (NOMA) scheme, here we propose a digital domain power division multiplexed (PDM) transmission technology which is fully compatible with current dual polarization (DP) coherent optical communication system. The coherent optical orthogonal frequency division multiplexing (CO-OFDM) modulation has been employed owing to its great superiority on high spectral efficiency, flexible coding, ease of channel estimation and robustness against fiber dispersion. And a PDM-DP-CO-OFDM system has been theoretically and experimentally demonstrated with 100 Gb/s wavelength division multiplexing (WDM) transmission over 1440 km standard single mode fibers (SSMFs).

    关键词： spectral efficiency,digital domain power division multiplexing,non-orthogonal multiple access,coherent optical OFDM,optical fiber transmission

    更新于2025-09-10 09:29:36

  • Non-Fullerene Based Printed Organic Photodiodes with High Responsivity and MHz Detection Speed

    摘要： Digitally printed organic photodiodes (OPDs) are of great interest for the cost-efficient additive manufacturing of single and multi-device detection systems with full freedom of design. Recently reported high-performance non-fullerene acceptors (NFAs) can address the crucial demands of future applications in terms of high operational speed, tunable spectral response as well as device stability. Here, we present the first demonstration of inkjet and aerosol-jet printed OPDs based on the high-performance NFA, IDTBR, in combination with poly(3-hexylthiophene) (P3HT) exhibiting a spectral response up to the NIR. These digitally printed devices reach record responsivities up to 300 mA/W in the visible and NIR spectrum competing with current commercially available technologies based on Si. Furthermore, their fast dynamic response with cut-off frequencies surpassing 2 MHz outperforms most of the state-of the-art organic photodiodes. The successful process translation from spincoating to printing is highlighted by the marginal loss in performance compared to the reference devices, which reach responsivities of 400mA/W and detection speeds of more than 4 MHz. The achieved high device performance and the industrial relevance of the developed fabrication process provide NFAs with an enormous potential for the development of printed photodetection systems.

    关键词： aerosol-jet printing,spectral responsivity,non-fullerene acceptor,inkjet printing,digital printing,organic photodiode

    更新于2025-09-10 09:29:36

  • [IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI, USA (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Robust Estimation of Pulse Rate from a Wrist-type PPG During Intensive Exercise

    摘要： Estimation of pulse rate from a wrist-type PPG during motion is a notoriously difficult problem because of the presence of motion artifact (MA) which corrupts the signal in both the time and frequency domains. In this paper, we propose a new method for deriving pulse rate under intense exercise conditions which employs Ensemble Empirical Mode Decomposition and power spectral analysis to extract the pulsatile component of the signal. The method was validated on an openly available database containing PPG and ground-truth ECG-derived pulse rate measurements from 12 subjects during a running experiment. Our proposed technique showed a high estimation accuracy with a mean absolute error of 2.14 bpm over the entire database and a correlation coefficient between the estimates and the ground truth of 0.98. Our approach matched the performance of the state-of-the-art TROIKA framework without utilizing simultaneously recorded accelerometry data to remove the MA component. With over 97.5% of estimates within a 10% margin from the ground truth, our technique shows a lot of potential for inclusion in next generation wrist-worn wearable monitors in both sports and clinical settings.

    关键词： Pulse rate,PPG,Ensemble Empirical Mode Decomposition,power spectral analysis,motion artifact

    更新于2025-09-10 09:29:36

  • Using Hyperspectral Data to Identify Crops in a Cultivated Agricultural Landscape - A Case Study of Taita Hills, Kenya

    摘要： Recent advances in hyperspectral remote sensing techniques and technologies allow us to more accurately identify larger range of crop species from airborne measurements. This study employs hyperspectral AISA Eagle VNIR imagery acquired with 9 nm spectral and 0.6 m spatial resolutions over a spectral range of 400 nm to 1000 nm. The area of study is the Taita hills in Kenya. Various crops are grown in this region basically for food and as an economic activity. The crops addressed are: maize, bananas, avocados, and sugarcane and mango trees. The main objectives of this study were to study what crop species can be distinguished from the cultivated population crops in the agricultural landscape and what feature space discriminates most effectively the spectral signatures of different species. Spectral Angle Mapper (SAM) algorithm together with some dissimilarity concepts was applied in this work. The spectral signatures for crops were collected using accurate field plot maps. Accuracy assessment was done using independent training vector data. We achieved an overall accuracy of 77% with a kappa value of 0.67. Various crops in different locations were identified and shown.

    关键词： Spectral angle mapper,Hyperspectral imaging,Spectral signatures,Spectral variation,Crop identification

    更新于2025-09-09 09:28:46

  • [IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Extended Linear Mixing Model in an Ecosytem with High Spectral Variability

    摘要： Hyperspectral imagery (HSI) has become an important tool in ecosystem conservation due to its capability to perform accurate spectral unmixing, for vegetation mapping and ecosystem monitoring. An issue to be solved is the spectral variability of endmembers that can be induced by sensor noise and topographic changes. This spectral variability is considered by the Extended Linear Mixing Model (ELMM), which is applied to a mountainous ecosystem with high spectral variability and radiometric changes in each swath. The results obtained are very satisfactory, achieving reasonable abundance estimations and accurate characterization of the variability within the scene. ELMM allows studying the features of each pixel, including additional information about the characterization of the mixed pixels, in HSI by taking spectral variability into account. Moreover, it is observed that ELMM is robust to the absence of pure pixels as well as to noise.

    关键词： ecosystem management,spectral unmixing,Hyperspectral imagery,spectral variability

    更新于2025-09-09 09:28:46

  • Selection and Fusion of spectral indices to improve water body discrimination

    摘要： Spectral indices are widely used to emphasize water body information in satellite images. The selection of the appropriate index is one of the tasks that the remote sensing community faces when water bodies are studied. In this work we propose an approach for the selecting and fusing of spectral indices, in order to improve water discrimination. Firstly, we compute several spectral indices and analyze their discrimination power taking into account the accuracy value. Through a hierarchical clustering applied only on indices with accuracy value greater than a certain threshold, we cluster the water indices into different groups. The result of the clustering depends on 2 factors: the discrimination capacity of the computed indices and the features of the studied water body. Indices in each group are fused by means of a linear combination. Therefore, we obtain an adaptive fusion of different spectral indices. The previous information is used to compute the likelihoods belonging to water and non-water. These values are the inputs for a probabilistic classification framework named Gaussian Markov Measure Field. According to our experimental work the proposed selection and fusion approach improves the discrimination power of the studied indices.

    关键词： spectral analysis,remote sensing,optimization,spectral water index,water resources

    更新于2025-09-09 09:28:46

  • [IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Fast and Easy Integration and Classification of Hyperspectral Optical and Thermal Data: A Mineral Mapping Case Study

    摘要： Independent spectral analysis is usually employed to analyse hyperspectral optical (visible: VIS, near infrared: NIR, shortwave infrared: SWIR) and thermal (longwave infrared: LWIR) data. The integration of the spectral information provided by different wavelength ranges and the subsequent complex classification still remains challenging. In this paper we will demonstrate the benefits of mineral classification employed to optical and thermal hyperspectral data (CASI and SASI: 0.4-2.5 μm; TASI: 8.6-11.5 μm) when using new tools (QUANTools) developed at the Czech Geological Survey (CGS). In this case study, the same approach was employed as published by Kopa?ková and Koucká (2017) [1], however, previously hyperspectral optical data were used together with multispectral long-wave infrared (LWIR) data. In this paper we demonstrate that the new concept, which was recently introduced, can be directly employed to CASI/SASI/TASI hyperspectral datasets and provide results in terms of mineral classification in a quick and easy way.

    关键词： mineral mapping,optical spectral region,CASI,data integration,imaging spectroscopy,TASI,SASI,thermal infrared spectral region

    更新于2025-09-09 09:28:46

  • A method to discern voltage dependent internal photoemission component from photoconductivity content in spectral response of metal-organic semiconductor-metal devices and evaluate the interface barriers

    摘要： The ability to detect and determine a typically weak internal photoemission (IPE) signal from a usually strong photoconductivity (PC) signal within a spectral response (SR) measurement can be helpful in studying the interface properties of metal-semiconductor junctions, which are often critical for proper design and analysis of semiconductor electronic devices including organic photovoltaic devices. In this report, we propose a method to discern the voltage dependent IPE component from PC content in a measured SR of organic devices. The method is based on the ratio of SR measured at different voltage bias conditions in metal-organic semiconductor-metal devices. The separated IPE component, hence, can be used to estimate the associated interface barrier(s). The differentiation between IPE and PC is probably caused due to the barrier changing at the metal and organic semiconductor interface on the application of bias which causes a modulation in IPE signal with the applied bias. In this work, a theoretical basis for the method of characterisation has been developed. Based on the analysis, as an example, the barriers between [6, 6] phenyl C61 butyric acid methyl ester (PCBM) and electrodes indium tin oxide and aluminium for different bias voltages have been evaluated. This simple and elegant method of studying metal and organic semiconductor barrier, when applicable, can be helpful in device design and characterisation.

    关键词： Spectral Response,Metal-Semiconductor Barrier,Bias Dependent Spectral Response,Internal Photoemission

    更新于2025-09-09 09:28:46