- 标题
- 摘要
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- 实验方案
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Individual Tree Crown Segmentation of a Larch Plantation Using Airborne Laser Scanning Data Based on Region Growing and Canopy Morphology Features
摘要： The detection of individual trees in a larch plantation could improve the management efficiency and production prediction. This study introduced a two-stage individual tree crown (ITC) segmentation method for airborne light detection and ranging (LiDAR) point clouds, focusing on larch plantation forests with different stem densities. The two-stage segmentation method consists of the region growing and morphology segmentation, which combines advantages of the region growing characteristics and the detailed morphology structures of tree crowns. The framework comprises five steps: (1) determination of the initial dominant segments using a region growing algorithm, (2) identification of segments to be redefined based on the 2D hull convex area of each segment, (3) establishment and selection of profiles based on the tree structures, (4) determination of the number of trees using the correlation coefficient of residuals between Gaussian fitting and the tree canopy shape described in each profile, and (5) k-means segmentation to obtain the point cloud of a single tree. The accuracy was evaluated in terms of correct matching, recall, precision, and F-score in eight plots with different stem densities. Results showed that the proposed method significantly increased ITC detections compared with that of using only the region growing algorithm, where the correct matching rate increased from 73.5% to 86.1%, and the recall value increased from 0.78 to 0.89.
关键词： airborne laser scanning (ALS),individual tree crown (ITC) segmentation,light detection and ranging (LiDAR),region growing,canopy morphology,larch plantation
更新于2025-09-19 17:13:59
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Research on the technology of abnormal discharge detection device for metal fittings based on optical fiber signal transmission
摘要： This paper aims to develop an abnormal discharge detection device based on optical fiber signal transmission, and realize the reliable detection of abnormal discharge between fittings of high voltage electrical equipment. The detector and visible light detector developed in the arc light detection part can realize the efficient detection of ultraviolet light and visible light in the arc light. By optical fiber far - range signal transmission structure, this design developed multifunctional optical signal collector, which can be converted into analog electric signal, state quantity signal, digital quantity signal and other forms while collecting arc light efficiently.
关键词： arc light detection,optical fiber signal transmission,abnormal discharge detection,high voltage electrical equipment
更新于2025-09-16 10:30:52
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Analysis and design of a hybrid optical fiber refractometer for large dynamic range measurements
摘要： In this paper, we report the outcomes of the 2015 data fusion contest organized by the Image Analysis and Data Fusion Technical Committee (IADF TC) of the IEEE Geoscience and Remote Sensing Society. As for previous years, the IADF TC organized a data fusion contest aiming at fostering new ideas and solutions for multisource studies. The 2015 edition of the contest proposed a multiresolution and multisensorial challenge involving extremely high resolution RGB images (with a ground sample distance of 5 cm) and a 3-D light detection and ranging point cloud (with a point cloud density of approximatively 65 pts/m2 ). The competition was framed in two parallel tracks, considering 2-D and 3-D products, respectively. In this Part B, we report the results obtained by the winners of the 3-D contest, which explored challenging tasks of road extraction and ISO containers identi?cation, respectively. The 2-D part of the contest and a detailed presentation of the dataset are discussed in Part A.
关键词： light detection and ranging (LiDAR),very high resolution (VHR) data,object identi?cation,multiresolution-data fusion,multisource-data fusion,multimodal-data fusion,Image analysis and data fusion (IADF),road detection
更新于2025-09-16 10:30:52
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European Microscopy Congress 2016: Proceedings || Improving 3d correlation in integrated correlated light and electron microscopy using confocal laser scanning microscopy
摘要： Integrated optoelectronics for fast and efficient light detection and imaging in the infrared and visible spectrum.
关键词： optoelectronics,visible spectrum,light detection,infrared,imaging
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Development of SPAD Based on Thermoelectrically Controlled Silicon Carbide Avalanche Photodiode
摘要： Single photon detectors, which are capable of ultra-sensitive detection in a low light level, have been widely used in a variety of applications such as remote sensing, biochemical science, and quantum information science. In particular, the rapid development of quantum information science has greatly improved the development of single photon detectors because it played a key role in achieving successful results in quantum key distribution and quantum communication. The single photon avalanche photodiodes (SPADs) are most conventional devices to detect photons because the APDs, the core elements of SPADs, are known to be advantageous to achieve cheap production and robust structure. In recent years, as the demand for ultraviolet light detection has increased, there have been actively reported on the development of APD detectors based on silicon carbide (SiC), which has a high gain only in the deep ultraviolet wavelength band. Here we report on the performance evaluation of lab-assembled SPAD based on SiC-APD.
关键词： ultraviolet light detection,quantum information science,Single photon detectors,SPAD,SiC-APD
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE SENSORS - Montreal, QC, Canada (2019.10.27-2019.10.30)] 2019 IEEE SENSORS - Identification of Legionella Species by Photogate-Type Optical Sensor
摘要： This work describes simple method for sensing bacteria, Legionella by using a photogate-type optical sensor (PG-sensor) and MEMS chip. We observed the behavior of fluorescence from Legionella dumoffii (L. dumoffii) and Legionella erythra (L. erythra) when they are exposed to ultraviolet light. The time dependence of the fluorescence intensity of L. dumoffii and L. erythra obtained with PG-sensor agreed well with that of fluorescence intensity obtained with spectrometer, showing that each Legionella is able to be detected by PG-sensor. Using the difference of their behavior, the identification of each bacterium was successfully performed for a mixed bacterial system of L. dumoffii and L. erythra by using the combination of PG-sensor and optical filters.
关键词： photogate,Legionella,Light detection sensor,fluorescence,Identification
更新于2025-09-16 10:30:52
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Simplified Method for Analyzing the Availability of Rooftop Photovoltaic Potential
摘要： This paper presents a new simpli?ed method for analyzing the availability of photovoltaic potential on roofs. Photovoltaic systems on roofs are widespread as they represent a sustainable and safe investment and, therefore, a means of energy self-su?ciency. With the growth of photovoltaic systems, it is also crucial to correctly evaluate their global e?ciency. Thus, this paper presents a comparison between known methods for estimating the photovoltaic potential (as physical, geographic and technical contributions) on a roof and proposes a new simpli?ed method, that takes into account the economic potential of a building that already has installed a photovoltaic system. The measured values of generated electricity of the photovoltaic system were compared with calculated photovoltaic potential. In general, the annual physical, geographic, technical and economic potentials were 1273.7, 1253.8, 14.2 MWh, and 279.1 Wh, respectively. The analysis of all four potentials is essential for further understanding of the sustainable and safe investment in photovoltaic systems.
关键词： light detection and ranging (LiDAR),photovoltaic system,rooftop photovoltaic potential,economic potential
更新于2025-09-16 10:30:52
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[IEEE 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD) - Kyoto, Japan (2019.7.2-2019.7.5)] 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD) - Effect of Device Structure on the Narrow-band Light Detection of Bulk Heterostructure Organic Photodetectors based on Poly(3-hexylthiophene) and Fullerene Derivative
摘要： The characteristics of organic photodetectors based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) blends with various film thicknesses of active layer are investigated. The red-shift in peak wavelength of incident-photon-to-current conversion efficiency (IPCE) spectra in the devices with various film thicknesses is observed with increasing film thickness. For thick devices upon irradiation by light with a photon energy of around energy gap of an active layer, excitons are formed almost uniformly because of the small absorption coefficient of red light. A conventional device with 2 μm-thick film exhibits narrow-band light detection with red-light sensitivity and the relatively narrow spectral response of the full-width at half-maximum (FWMH) of around 50 nm. On the other hand, an inverted device with 2 μm-thick film exhibits broadband light detection. For bulk heterostructure devices, one of important factors to realize the narrowband light detection is the control of charge carrier collection efficiency at electrodes which is attributed to the device structure, including the intrachain transport in polymer.
关键词： PCBM,bulk heterostructure,organic photodetectors,narrow-band light detection,P3HT
更新于2025-09-12 10:27:22
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Estimating below‐canopy light regimes using airborne laser scanning: An application to plant community analysis
摘要： Light is a key driver of forest biodiversity and functioning. Light regimes beneath tree canopies are mainly driven by the solar angle, topography, and vegetation structure, whose three‐dimensional complexity creates heterogeneous light conditions that are challenging to quantify, especially across large areas. Remotely sensed canopy structure data from airborne laser scanning (ALS) provide outstanding opportunities for advancement in this respect. We used ALS point clouds and a digital terrain model to produce hemispherical photographs from which we derived indices of nondirectional diffuse skylight and direct sunlight reaching the understory. We validated our approach by comparing the performance of these indices, as well as canopy closure (CCl) and canopy cover (CCo), for explaining the light conditions experienced by forest plant communities, as indicated by the Landolt indicator values for light (Llight) from 43 vegetation surveys along an elevational gradient. We applied variation partitioning to analyze how the independent and joint statistical effects of light, macro‐climate, and soil on the spatial variation in plant species composition (i.e., turnover, Simpson dissimilarity, βSIM) depend on light approximation methodology. Diffuse light explained Llight best, followed by direct light, CCl and CCo (R2 = .31, .23, .22, and .22, respectively). The combination of diffuse and direct light improved the model performance for βSIM compared with CCl and CCo (R2 = .30, .27 and .24, respectively). The independent effect of macroclimate on βSIM dropped from an R2 of .15 to .10 when diffuse light and direct light were included. The ALS methods presented here outperform conventional approximations of below‐canopy light conditions, which can now efficiently be quantified along entire horizontal and vertical forest gradients, even in topographically complex environments such as mountains. The effect of macroclimate on forest plant communities is prone to be overestimated if local light regimes and associated microclimates are not accurately accounted for.
关键词： canopy structure,forest biodiversity,remote sensing,light availability,microclimate,Ellenberg indicator value,beta diversity,hemispherical photography,biodiversity,airborne light detection and ranging LiDAR
更新于2025-09-11 14:15:04
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Highly Sensitive, Fast Response Perovskite Photodetectors Demonstrated in Weak Light Detection Circuit and Visible Light Communication System
摘要： Organic–inorganic hybrid perovskite (OIHP) photodetectors have presented unprecedented device performance mainly owing to outstanding material properties. However, the solution-processed OIHP polycrystalline thin films with defective surface and grain boundaries always impair the key parameter of photodetectors. Herein, a nonfullerene passivation layer exhibits more efficient passivation for OIHP materials to dramatically reduce the trap density of state, yielding a dark current as low as 2.6 × 10?8 A cm ?2 under ?0.1 V. In addition, the strong absorption in near-infrared (NIR) region of nonfullerene/C60 heterojunction broadens the detectable range to over 900 nm by effective charge transport, ultimately leading to a specific detectivity of 1.45 × 1012 and 7.37 × 1011 cm Hz1/2 W?1 at 650 and 820 nm, respectively. Encouragingly, the response speed of 27 ns is obtained at 0.6 mm2 of device area by removing constrain from the resistance–capacitance constant. Moreover, the prominent practical application of the photodetector is demonstrated in a weak light detection circuit and a visible light communication system. It is believed that the OIHP photodetectors with high sensitivity, NIR photoresponse, and ultrafast speed would pave the way to commercial applications.
关键词： weak light detection circuit,perovskite photodetectors,fast response,visible light communication,highly sensitive
更新于2025-09-11 14:15:04