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3D Vehicle Model-based PTZ Camera Auto-calibration for Smart Global Village
摘要： PTZ cameras perform an important part for the surveillance systems in the highway because of their wide field of vision and high flexibility. However, it is difficult to obtain real world physical information accurately by using the image information due to the change in the focal length and angles of the PTZ cameras with the surveillance requirements. Therefore, it is of great value to study off-site auto-calibration method for PTZ cameras in the application of highway surveillance system. This paper proposes a PTZ camera auto-calibration method based on vanishing point constraints and 3D vehicle model constraints to establish an accurate description relationship between image information and real-world physical information. Firstly, the position of vertical vanishing point is estimated accurately using the cascaded Hough Transform voting of the vehicle target motion trajectories. Secondly, the physical size of the 3D vehicle model is used as a constraint, and it is combined with an enumeration strategy to obtain the accurate estimation of the lateral vanishing point. Finally, the calibration parameters of the PTZ camera are calculated with the known camera height. The experiments on numerous sets of highway surveillance scenes show that the proposed auto-calibration method of the PTZ camera is able to satisfy the application requirements of the highway surveillance scenes. Compared with the reference methods, this method has a good performance. Moreover, this method has some value for different application.
关键词： highway,auto-calibration,vanishing point,3D vehicle model,PTZ camera
更新于2025-09-23 15:22:29
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Monometallic Catalytic Models Hosted in Stable Metal-Organic Frameworks for Tunable CO2 Photoreduction
摘要： The photocatalytic reduction of CO2 to energy carriers has emerged as one of the most promising strategy to alleviate the energy crisis and CO2 pollution, for which the development of catalyst was considered as the determining factor for the accomplishment of this conversion process. In this study, three stably and isostructural metal organic frameworks (denoted as MOF-Ni, MOF-Co and MOF-Cu), have been synthesized and used as heterogeneous catalysts applied into photocatalytic CO2 reduction reaction (CO2RR). It is worth noting that the MOF-Ni exhibited a very high selectivity of 97.7% for photoreducing CO2 to CO, which has exceeded most of the reported MOF-based catalysts in the field. Significantly, the MOFs associated with monometallic catalytic centre offer a simply and precisely structural model which allows us to understand the specific effects of different metal ion species on photoreduction of CO2 as well as reactive mechanism more intuitively.
关键词： Isostructural,Metal-Organic Frameworks,Photocatalytic CO2 Reduction,High Selectivity,Monometallic Catalytic Model,Reactive Mechanism
更新于2025-09-23 15:22:29
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Raman spectroscopic analysis of testicular lamina propria predicts spermatogenesis in a mouse infertility model
摘要： The status of the testicular lamina propria (LP) is associated with spermatogenesis. The aim of this study was to determine whether Raman spectroscopy (RS) could detect material components within the LP and predict spermatogenesis. Twenty adult male mice were divided into a busulfan-treated group (n ? 16 mice receiving a single injection of 50 mg kg(cid:2)1, i.p., busulfan) and a control group (n ? 4 mice receiving an equivalent volume of 0.9% saline solution injected i.p.). Mice were killed 2, 4, 6 and 8 weeks after injection of busulfan or saline solution (n ? 1 control and 4 busulfan-treated mice at each time point). The testicular tubules were assessed by RS and compared with histopathological observations. Control tubules had raw spectral intensities below 2000 arbitrary units, whereas busulfan tubules had strengthened intensities that peaked at Week 4 (absent spermatogenesis) and returned to normal levels at Week 8 (restored spermatogenesis). The change in the LP revealed by RS occurred before the change in spermatogenesis detected by histopathology. Correspondingly, the sensitivity/specificity of RS for distinguishing busulfan-treated and control tubules at 2, 4, 6 and 8 weeks were 65.00%/70.00%, 95.00%/100.00%, 40.00%/100.00% and 25.00%/95.00% respectively. Collectively, RS could be used to evaluate the status of the LP and as a complement to histopathological evaluation to predict tubules with the potential to develop spermatogenesis for infertile patients.
关键词： spermatogenesis,busulfan,mouse infertility model,testicular lamina propria,Raman spectroscopy
更新于2025-09-23 15:22:29
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Phasor Quaternion Neural Networks for Singular Point Compensation in Polarimetric-Interferometric Synthetic Aperture Radar
摘要： Interferograms obtained by synthetic aperture radar often include many singular points (SPs), which makes it difficult to generate an accurate digital elevation model. This paper proposes a filtering method to compensate SPs adaptively by using polarization and phase information around the SPs. Phase value is essentially related to polarization changes in scattering as well as propagation. In order to handle the polarization and phase information simultaneously in a consistent manner, we define a new number, phasor quaternion (PQ), by combining quaternion and complex amplitude, with which we construct the theory of PQ neural networks (PQNNs). Experiments demonstrate that the proposed PQNN filter compensates SPs very effectively. Even in the situations where the conventional methods deteriorate in their performance, it realizes accurate compensation, thanks to its good generalization characteristics in integrated Poincare-sphere polarization space and the complex-amplitude space. We find that PQNN is an excellent framework to deal with the polarization and phase of electromagnetic wave adaptively and consistently.
关键词： Complex-valued neural network (CVNN),phase singular point,polarimetric interferometric synthetic aperture radar (PolInSAR),quaternion neural network (QNN),digital elevation model (DEM)
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Monostatic GTD Model for Double Scattering due to Specular Reflections or Edge Diffractions
摘要： GTD model is a good candidate to extract the features of radar targets, which describes the frequency dependence of scattering centers for many geometries or mechanisms and can represent the attribute information of the geometrical structures. The mechanisms associated with this model have been proven to include single reflection, single diffraction and multiple reflections from dihedral and trihedral corner reflectors. However, multi-scattering mechanisms from more complex structures are not studied adequately. In this paper, we expand the GTD model to any double scattering due to specular reflections or edge diffractions, and derive the related frequency-dependence factor. Finally, a simulation validates the theory.
关键词： specular reflection,multiple scattering mechanism,frequency-dependence factor,flat surface,straight edge,doubly-curved surface,GTD model,curved edge,edge diffraction,singly-curved surface
更新于2025-09-23 15:22:29
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[IEEE 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Vladivostok, Russia (2018.10.3-2018.10.4)] 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Numerical Simulation of Low-Coherence Radiation Propagation in Turbid Media and Structural Image Reconstruction in Endoscopic Optical Coherence Tomography with Allowance for Speckle Fluctuations
摘要： A method of Monte Carlo simulation of low-coherence radiation propagation in turbid media with consideration of speckle noise (the result of mutual interference of secondary spherical waves) is described. The process of photon propagation within investigated object, such as biological tissue, includes the following steps: the photon injection, mean free path determination, the verification of the fulfillment of the boundary condition, the absorption and scattering. Structural image reconstruction in optical coherence tomography (OCT) with consideration of speckle fluctuations is made by summation the statistical weight of the beam coming out of the investigated object inside the detector area with the intensity of a series of pixels of the current A-scan. The key feature of the presented method is the description of the investigated object geometry. Three-dimensional array of voxels combined into parallelograms, and the border cross checking is carried out by using an improved Smith algorithm. The described method can be used to obtain high-quality endoscopic structural OCT images of body cavities and tracts (diagnosis of the respiratory tract, cardiovascular system, gastrointestinal tract, genitourinary system, etc.).
关键词： coherence probing depth,Monte Carlo simulation,optical coherence tomography,voxel based model,speckle fluctuations,structural image
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE Power & Energy Society General Meeting (PESGM) - Portland, OR, USA (2018.8.5-2018.8.10)] 2018 IEEE Power & Energy Society General Meeting (PESGM) - A Multiobjective Voltage Unbalance Factor for PV Hosting Capacity with Probabilistic ZIP Load Models
摘要： This paper proposes a multiobjective voltage unbalance factor to estimate single-phase photovoltaic (PV) hosting capacity in 3-phase residential networks. This factor is derived from a combination of various components, including zero and negative-sequence voltage unbalance factors associated with the inherent variability and uncertainty of both loads and PV generation. A time-varying probabilistic ZIP load model is also incorporated in the proposed factor to characterize the uncertainty of voltage-dependent loads within each hour of a day over four seasons. The location, size and phase allocation of PV units are randomly generated. Simulation results obtained on a modified IEEE 4-bus test feeder and the IEEE European low voltage test feeder show that the developed approach can provide a better response to the hourly-varying and uncertain behaviors of loads and generation.
关键词： PV hosting capacity,voltage unbalance,power quality,probabilistic ZIP load model,Distribution system
更新于2025-09-23 15:22:29
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Speckle Noise Reduction of Medical Imaging via Logistic Density in Redundant Wavelet Domain
摘要： In the digital world, artificial intelligence tools and machine learning algorithms are widely applied in analysis of medical images for identifying diseases and make diagnoses; for example, to make recognition and classification. Speckle noises affect all medical imaging systems. Therefore, reduction in corrupting speckle noises is very important, since it deteriorates the quality of the medical images and makes tasks such as recognition and classification difficult. Most existing denoising algorithms have been developed for the additive white Gaussian noise (AWGN). However, AWGN is not a speckle noise. Therefore, this work presents a novel speckle noise removal algorithm within the framework of Bayesian estimation and wavelet analysis. This research focuses on noise reduction by the Bayesian with wavelet-based method because it provides good efficiency in noise reduction and spends short time in processing. The subband decomposition of a logarithmically transformed image is best described by a family of heavy-tailed densities such as Logistic distribution. Then, this research proposes the maximum a posteriori (MAP) estimator assuming Logistic random vectors for each parent-child wavelet coefficient of noise-free log-transformed data and log-normal density for speckle noises. Moreover, a redundant wavelet transform, i.e., the cycle-spinning method, is applied in our proposed methods. In our experiments, our proposed methods give promising denoising results.
关键词： wavelet transforms.,Bayesian estimation,speckle noise,non-Gaussian model
更新于2025-09-23 15:22:29
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Dynamic Photo-Electro-Thermal Modeling of Light-Emitting Diodes with Phosphor Coating as Light Converter
摘要： Based on the dynamic Photo-Electro-Thermal (PET) theory for LED systems, a comprehensive theory for analyzing and modeling phosphor coating in white light-emitting diodes (LEDs) as a dynamic light converter has been presented in Part-I of this paper. This Part-2 of the work provides the details of the model parameter determination, model setup and experimental verification. The procedures of obtaining the parameters in the experimental setup are explained. Using the comprehensive theory, a dynamic PET computer model of a phosphor-coated LED device has been developed. The simulation results compare well with the practical measurements, confirming the validity of the comprehensive theory in Part-1 of this paper. The new model provides novel equations for new information such as the power loss in phosphor coating and transients of the light emitted from the phosphor coating. Such information can be used for the designs of LED drivers and systems.
关键词： Phosphor-coated light-emitting diodes (PC-LED),complete PET model,photo-electro-thermal (PET) theory,light converter
更新于2025-09-23 15:22:29
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New Dynamic Photo-Electro-Thermal Modeling of Light-Emitting Diodes with Phosphor Coating as Light Converter
摘要： Phosphor-coated light-emitting diode (PC-LED) is the dominant LED technology for public lighting. This paper presents a comprehensive theory for analyzing and modeling phosphor coating in white light-emitting diodes (LEDs) as a dynamic light converter. The new PC-LED model not only obeys the traditional diode equation, it includes the energy-storage and transient effects of the phosphor coating. Major control variables include energy storage in and the luminous flux from the phosphor coating. This new model enables the dynamic variations of luminous flux and energy storage and power loss in phosphor-coating to be accurately predicted. Part-1 of this paper provides the details of the theory and analysis leading to the new PC-LED model under the framework of the photo-electro-thermal theory. Details of the model parameter determination, model setup and experimental verification are included in Part-2. The model offers the important power loss equation of the phosphor coating which highlights the factors affecting the heat loss and the coating’s blackening effects. This equation can be used by engineers to design LED drivers in order to reduce the coating temperature and the blackening effects and to prolong LED lifetime.
关键词： Phosphor-coated light-emitting diodes (PC-LED),flux capacitor,light converter.,photo-electro-thermal (PET) theory,dynamic model of PC-LED
更新于2025-09-23 15:22:29