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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Blind Nonlinear Hyperspectral Unmixing Using an <tex>$\ell_{q}$</tex> Regularizer
摘要： Hyperspectral unmixing consists of estimating pure material spectra (endmembers) and their corresponding abundances in hyperspectral images. In this paper, a blind nonlinear hyperspectral unmixing algorithm is presented. The algorithm promotes sparse abundance maps using an lq regularizer and assumes that the spectra are mixed according to an extension to generalized bilinear model, called the Fan model. The algorithm is evaluated using both simulated and real hyperspectral data.
关键词： non-negative matrix factorization,Spectral unmixing,bilinear model,hyperspectral images
更新于2025-09-23 15:22:29
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Compressive Phase Retrieval Realized by Combining Generalized Approximate Message Passing with Cartoon-Texture Model
摘要： Generalized approximate message passing (GAMP) can be applied to compressive phase retrieval (CPR) with excellent phase-transition behavior. In this paper, we introduced the cartoon-texture model into the denoising-based phase retrieval GAMP(D-prGAMP), and proposed a cartoon-texture model based D-prGAMP (C-T D-prGAMP) algorithm. Then, based on experiments and analyses on the variations of the performance of D-PrGAMP algorithms with iterations, we proposed a 2-stage D-prGAMP algorithm, which makes tradeoffs between the C-T D-prGAMP algorithm and general D-prGAMP algorithms. Finally, facing the non-convergence issues of D-prGAMP, we incorporated adaptive damping to 2-stage D-prGAMP, and proposed the adaptively damped 2-stage D-prGAMP (2-stage ADD-prGAMP) algorithm. Simulation results show that, runtime of 2-stage D-prGAMP is relatively equivalent to that of BM3D-prGAMP, but 2-stage D-prGAMP can achieve higher image reconstruction quality than BM3D-prGAMP. 2-stage ADD-prGAMP spends more reconstruction time than 2-stage D-prGAMP and BM3D-prGAMP. But, 2-stage ADD-prGAMP can achieve PSNRs 0.2 ～ 3 dB higher than those of 2-stage D-prGAMP and 0.3 ～ 3.1 dB higher than those of BM3D-prGAMP.
关键词： cartoon-texture model,generalized approximate message passing,adaptive damping,compressive phase retrieval
更新于2025-09-23 15:22:29
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Simplified Vehicle Vibration Modeling for Image Sensor Communication
摘要： Image sensor communication (ISC), derived from visible light communication (VLC) is an attractive solution for outdoor mobile environments, particularly for intelligent transport systems (ITS). In ITS-ISC, tracking a transmitter in the image plane is critical issue since vehicle vibrations make it difficult to select the correct pixels for data reception. Our goal in this study is to develop a precise tracking method. To accomplish this, vehicle vibration modeling and its parameters estimation, i.e., representative frequencies and their amplitudes for inherent vehicle vibration, and the variance of the Gaussian random process representing road surface irregularity, are required. In this paper, we measured actual vehicle vibration in a driving situation and determined parameters based on the frequency characteristics. Then, we demonstrate that vehicle vibration that induces transmitter displacement in an image plane can be modeled by only Gaussian random processes that represent road surface irregularity when a high frame rate (e.g., 1000 fps) image sensor is used as an ISC receiver. The simplified vehicle vibration model and its parameters are evaluated by numerical analysis and experimental measurement and obtained result shows that the proposed model can reproduce the characteristics of the transmitter displacement sufficiently.
关键词： vehicle motion model,vehicle vibration,visible light communication,image sensor communication,road surface irregularity,transmitter displacement
更新于2025-09-23 15:22:29
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Modeling the threshold voltage variation induced by channel random dopant fluctuation in fully depleted silicon-on-insulator MOSFETs
摘要： In nanoscale fully depleted silicon-on-insulator (FD-SOI) MOSFETs, the standard deviation of threshold voltage (σVth) caused by random dopant fluctuation (RDF) is an important parameter to predict the performance of transistors and circuits. In this paper, an analytic model of σVth considering both the dopant 'number' and dopant 'position' fluctuation in channels is proposed. A new model of σVth,num caused by 'number' is given and the method of obtaining the 'position' influence ratio Rp is discussed in this paper. Moreover, the simulation methods are analyzed in detail. The calculated σVth values in FD-SOI MOSFETs are compared with the Sentaurus TCAD simulation results at different channel lengths, channel doping concentrations, SOI film thicknesses, front gate oxide thicknesses, and buried-oxide thicknesses. The comparison shows that the proposed model matches well with the obtained numerical simulation results.
关键词： threshold voltage variation,analytical model,fully depleted silicon-on-insulator MOSFETs,Sentaurus TCAD simulation,random dopant fluctuation
更新于2025-09-23 15:22:29
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The Application of a New Model-Based Iterative Reconstruction in Low-Dose Upper Abdominal CT
摘要： Rationale and Objectives: To compare upper abdominal computed tomography (CT) image quality of new model-based iterative reconstruction (MBIR) with low-contrast resolution preference (MBIRNR40), conventional MBIR (MBIRc), and adaptive statistical iterative reconstruction (ASIR) at low dose with ASIR at routine-dose. Materials and Methods: Study included phantom and 60 patients who had initial and follow-up CT scans. For patients, the delay phase was acquired at routine-dose (noise index = 10 HU) for the initial scan and low dose (noise index = 20 HU) for the follow-up. The low-dose CT was reconstructed with 40% and 60% ASIR, MBIRc, and MBIRNR40, while routine-dose CT was reconstructed with 40% ASIR. CT value and noise measurements of the subcutaneous fat, back muscle, liver, and spleen parenchyma were compared using one-way ANOVA. Two radiologists used semiquantitative 7-scale (-3 to +3) to rate image quality and artifacts. Results: The phantom study revealed superior low-contrast resolution with MBIRNR40. For patient scans, the CT dose index for the low-dose CT was 3.00 ± 1.32 mGy, 75% lower than the 11.90 ± 4.75 mGy for the routine-dose CT. Image noise for the low-dose MBIRNR40 images was significantly lower than the low-dose MBIRc and ASIR images, and routine-dose ASIR images (p < 0.05). Subjective ratings showed higher image quality for low-dose MBIRNR40, with lower noise, better low-contrast resolution for abdominal structures, and finer lesion contours than those of low-dose MBIRc and ASIR images, and routine-dose ASIR images (p < 0.05). Conclusion: MBIRNR40 with low-contrast resolution preference provides significantly lower noise and better image quality than MBIRc and ASIR in low-dose abdominal CT; significantly better objective and subjective image quality than the routine-dose ASIR with 75% dose reduction.
关键词： Model-based iterative reconstruction,Abdominal CT.,X-ray computed tomography,Adaptive statistical iterative reconstruction,Radiation dose
更新于2025-09-23 15:22:29
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A fast scheme for renal microvascular perfusion functional imaging: Assessed by an imaging quality evaluation model
摘要： Purpose: This study aimed to develop a fast scheme of multiparametric perfusion functional imaging (PFI) based on dynamic contrast-enhanced ultrasound (DCEUS) for assessing renal microvascular hemodynamics. Method: The flow process in the DCEUS-based PFI was modified step-by-step to improve its operational efficiency, which was validated through in vivo renal perfusion experiments. A multiparametric model with a comprehensive coefficient of imaging quality (CIQ) was then built on four terms of the average information entropy, contrast, gray, and noise coefficient of PFIs to evaluate the sacrifice of imaging quality during modifications of DCEUS-based PFI. Results: The multiparametric model successfully evaluated modifications of DCEUS-based PFI from multiple perspectives (R2 = 0.73, P < 0.01). Compared with the raw scheme in the renal sagittal and coronal planes, the fast PFI scheme significantly improved its operational efficiency by 62.82 ± 1.07% (P < 0.01) and the nine PFIs simultaneously maintained a similar CIQ of 0.26 ± 0.06. Conclusions: The inhomogeneous hemodynamic distributions with a ring-like feature in the renal microvasculature were accurately and efficiently characterized by the fast PFI scheme. The fast PFI scheme can be applied for early diagnosis, follow-up evaluation and monitoring treatment of chronic kidney disease.
关键词： modification,coefficient of imaging quality,perfusion functional imaging,multiparametric model,dynamic contrast-enhanced ultrasound
更新于2025-09-23 15:22:29
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Thermal effects of a novel electrosurgical device for focused preparation in breast surgery tested in a specified porcine tissue ex vivo breast model using infrared measurement
摘要： Purpose This article investigates the qualities and thermal effects of a novel electrosurgical device (PT) which has been designed by ERBE Elektromedizin GmbH, Germany, for the preparation of critical locations such as in skin-sparing or nipple-sparing techniques and compares it to a standard device (SD) in a porcine ex vivo breast model using an heat map generated by infrared thermography. Methods In total, 42 abdominal wall specimens of porcine tissue consisting of the skin and the underlying subcutaneous and muscle layer were alternately dissected using one of the devices and pre-settings. During the preparation with the two devices, the epicutaneous temperature was measured by an infrared camera (VarioCam, Jenoptik, Germany) and the maximum temperature as well as the slope of the temperature rise was analysed. Results The use of PT shows significantly lower values for ΔTmax compared to SD. This effect was independent from the chosen mode. Using the same instrument in different modes, the use of AutoCut mode showed a significant reduction of ΔTmax at all indicated time points (SD: p < 0.0001 and PT: p < 0.0001). In summary, the combination of AutoCut + PT showed the lowest rise in temperature, whereas the combination of DryCut + SD led to the highest rise in temperature. The temperature difference between these two settings was 13.84 °C, which means a possible temperature reduction of 67% can be achieved by the right choice of device and its tailored mode. Conclusions The novel PT shows a significant reduction in epicutaneous temperature and a significant reduction of the slope of temperature rise most probably by a more focused application of energy compared to SD.
关键词： Infrared thermography,Porcine model,Electrosurgery,Mastectomy
更新于2025-09-23 15:22:29
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Electro-thermal modeling for InxGa1-xN/GaN based quantum well heterostructures
摘要： The joint effect of the heat transfer and the electronic properties in the InGaN/GaN based quantum well (QW) heterostructures has been investigated theoretically and numerically. One-dimensional Schr?dinger equation solver coupled with Poisson equation solver and Dual-phase-lagging (DPL) heat conduction solver has been developed. The numerical results suggest that the DPL heat conduction equations capture the microscale responses caused by the phonon-electron interaction. Both effects of the polarization charge and conduction band offset between the InGaN/GaN interfaces lead to the creation of the two-dimensional electron gas (2DEG) on the lower interface of the QW. It is found that the 2DEG density at the triangular quantum well increases with increasing Indium (In) composition. This increase is the same for the conduction band offset and the electron density. As a consequence, an increase of the heat dissipation and the temperature is observed at the lower interface of the quantum well.
关键词： Indium composition,Polarization charge,Nanoscale heat transfer,Dual-phase-lagging model,InGaN heterostructure
更新于2025-09-23 15:22:29
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Study on the measurement error and scope of analytical gradient model in phase measuring deflectometry
摘要： The existing analytical gradient models in phase measuring de?ectometry (PMD) usually su?er in the ambiguous problem. To solve this problem, simpli?cation/assumption is often given to the surface shape, which causes non-ignorable measurement error in certain situations. In order to analyze the relation between the surface shape and measurement error when simpli?cation/assumption is used, a ray tracing simulation model is developed in this paper. For any given PMD system setup, the relation between the height/slope variations of test surface and measurement accuracy can be carried out. The corresponding experiment work proves the correctness of this simulation model. The increasing of either the height or slope of object will lead to the exponential aggravating of measurement error. For our experiment setup, the measurement gradient error will be less than 0.5% if the ratio of the distance between the LCD (Liquid Crystal Display) screen and the reference plane and the STD (standard derivation) of object height is larger than 200.
关键词： Phase measuring de?ectometry,Error analysis,Ray tracing model,Optical 3D measurement
更新于2025-09-23 15:22:29
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QRCI: A new quantum representation model of color digital images
摘要： In this paper, a new quantum representation model of color digital images (QRCI) is investigated, in which the color information is encoded by the basis states of qubit sequences. QRCI model utilizes 2n+6 qubits to store a color digital image with size 2n×2n. Compared with the existing NCQI representation model, the storage capacity of QRCI improves 218 times. Moreover, some quantum color image processing operations concerning channels and bit-planes based on QRCI are discussed and their quantum circuits are designed. Comparison results of the quantum circuits indicate that these operations based on QRCI have lower quantum cost than NCQI. Therefore, the new proposed QRCI representation model can save more storage space and it is more convenient to conduct quantum color image processing operations concerning channels and bit-planes. This work will help the researchers to further investigate more complex quantum color image processing operations based on QRCI.
关键词： Quantum computation,Quantum cost,Quantum image representation model,Quantum color image processing,Storage capacity,Qubit
更新于2025-09-23 15:22:29