- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Comparison of Raw Data-Based and Complex Image-Based Sparse SAR Imaging Methods
摘要： Sparse signal processing has already been introduced to synthetic aperture radar (SAR), which shows potential in improving imaging performance based on raw data or a complex image. In this paper, the relationship between a raw data-based sparse SAR imaging method (RD-SIM) and a complex image-based sparse SAR imaging method (CI-SIM) is compared and analyzed in detail, which is important to select appropriate algorithms in different cases. It is found that they are equivalent when the raw data is fully sampled. Both of them can effectively suppress noise and sidelobes, and hence improve the image performance compared with a matched filtering (MF) method. In addition, the target-to-background ratio (TBR) or azimuth ambiguity-to-signal ratio (AASR) performance indicators of RD-SIM are superior to those of CI-SIM in down-sampling data-based imaging, nonuniform displace phase center sampling, and sparse SAR imaging model-based azimuth ambiguity suppression.
关键词： down-sampling,azimuth-range decouple,azimuth ambiguity,Lq regularization,SAR imaging,displaced phase center antenna (DPCA)
更新于2025-09-19 17:15:36
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All-printed, low-cost, tunable sensing range strain sensors based on Ag nanodendrite conductive inks for wearable electronics
摘要： Flexible and wearable strain sensors with high stretchability and high sensitivity have been studied intensively. However, the achievement of low-cost, rapid mass production and high performance of wearable strain sensors remains a challenge. In this study, Ag nanodendrite (ND) inks with good printability for varieties of substrates are prepared, which can be directly screen-printed onto nitrile rubber to manufacture strain sensors. Printed strain sensors (PSSs) with diverse working strain ranges and sensitivities can be simultaneously obtained by printing versatile geometric patterns. Comparatively, straight-line PSSs with a linewidth of 2 mm exhibit high electrical conductivity (1.14 × 10^5 S m^-1), a large sensing range (105%), high sensitivity (maximum gauge factor = 294.3), an ultra-fast response time (18 ms), and long-term stability (more than three weeks). Additionally, the sensing mechanism of the PSSs is further investigated by observing their surface topographies. Eventually, a smart glove based on PSSs is used for monitoring human motion (finger bending, wrist bending, walking, etc.) and gesture actions, demonstrating the potential applications of Ag ND-based PSSs in wearable electronic devices and human–machine interaction intelligent systems.
关键词： strain sensor,tunable sensing range,wearable electronics,screen printing,Ag nanodendrite
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE International Conference on Consumer Electronics - Asia (ICCE-Asia) - Jeju (2018.6.24-2018.6.26)] 2018 IEEE International Conference on Consumer Electronics - Asia (ICCE-Asia) - Robust HDR Video Synthesis Using Superpixel-Based Illumination Invariant Motion Estimation
摘要： We propose a novel high dynamic range (HDR) video synthesis algorithm from alternatively exposed low dynamic range (LDR) videos. We first develop a superpixel-based motion estimation technique using an illumination-invariant feature descriptor. Then, we merge the warped frames to obtain the HDR frame. Experimental results demonstrate that the proposed algorithm provides high-quality HDR videos compared to state-of-the-art algorithms.
关键词： High dynamic range (HDR) video,HDR imaging
更新于2025-09-19 17:15:36
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[IEEE 2018 International Conference on Information and Communication Technology Convergence (ICTC) - Jeju (2018.10.17-2018.10.19)] 2018 International Conference on Information and Communication Technology Convergence (ICTC) - Deep Inverse Tone Mapping Optimized for High Dynamic Range Display
摘要： The popularity of high dynamic range (HDR) makes the inverse tone mapping become an important technique for HDR display. In this paper, we propose a convolutional neural network (CNN) based inverse tone mapping method to generate a high-quality HDR image from one single standard dynamic range (SDR) image. First, we present a CNN design with a three-channel input, which considers both luminance and chrominance. Second, we propose to use overlapped inputs to remove the boundary artifacts, caused by zero padding in CNN. Experimental results demonstrate the high quality of our generated HDR images compared to the ground truth and conventional inverse tone mapping methods.
关键词： inverse tone mapping,high dynamic range imaging,convolutional neural networks
更新于2025-09-19 17:15:36
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A Wide Dynamic Range NUC Algorithm for IRCS Systems
摘要： Uniformity is a key feature of state-of-the-art infrared focal planed array (IRFPA) and infrared imaging system. Unlike traditional infrared telescope facility, a ground-based infrared radiant characteristics measurement system with an IRFPA not only provides a series of high signal-to-noise ratio (SNR) infrared image but also ensures the validity of radiant measurement data. Normally, a long integration time tends to produce a high SNR infrared image for infrared radiant characteristics radiometry system. In view of the variability of and uncertainty in the measured target’s energy, the operation of switching the integration time and attenuators usually guarantees the guality of the infrared radiation measurement data obtainted during the infrared radiant characteristics radiometry process. Non-uniformity correction (NUC) coe?cients in a given integration time are often applied to a speci?ed integration time. If the integration time is switched, the SNR for the infrared imaging will degenerate rapidly. Considering the e?ect of the SNR for the infrared image and the infrared radiant characteristics radiometry above, we propose a-wide-dynamic-range NUC algorithm. In addition, this essasy derives and establishes the mathematical modal of the algorithm in detail. Then, we conduct veri?cation experiments by using a ground-based MWIR(Mid-wave Infared) radiant characteristics radiometry system with an ?400 mm aperture. The experimental results obtained using the proposed algorithm and the traditional algorithm for di?erent integration time are compared. The statistical data shows that the average non-uniformity for the proposed algorithm decreased from 0.77% to 0.21% at 2.5 ms and from 1.33% to 0.26% at 5.5 ms. The testing results demonstrate that the usage of suggested algorithm can improve infrared imaging quality and radiation measurement accuracy.
关键词： Infrared radiation,Cooling infrared focal plane array,Non-uniformity correction,Wide dynamic range
更新于2025-09-19 17:15:36
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Valence and core excitons in solids from velocity-gauge real-time TDDFT with range-separated hybrid functionals: An LCAO approach
摘要： An atomic-orbital basis set framework is presented for carrying out velocity-gauge real-time time-dependent density functional theory (TDDFT) simulations in periodic systems employing range-separated hybrid functionals. Linear optical response obtained from real-time propagation of the time-dependent Kohn-Sham equations including nonlocal exchange is considered in prototypical solid-state materials such as bulk Si, LiF and monolayer hexagonal-BN. Additionally core excitations in monolayer hexagonal-BN at the B and N K-edges are investigated and the role of long-range and short-range nonlocal exchange in capturing valence and core excitonic effects is discussed. Results obtained using this time-domain atomic orbital basis set framework are shown to be consistent with equivalent frequency-domain planewave results in the literature. The developments discussed lead to a time-domain generalized Kohn-Sham TDDFT implementation for the treatment of core and valence electron dynamics and light-matter interaction in periodic solid-state systems.
关键词： Core-level spectroscopy,TDDFT,Solid-state,Real-time,Excitons,Range-separated hybrid
更新于2025-09-19 17:15:36
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Ultrafast and broadband photodetectors based on a perovskite/organic bulk heterojunction for large-dynamic-range imaging
摘要： Organic-inorganic hybrid perovskite (OIHP) photodetectors that simultaneously achieve an ultrafast response and high sensitivity in the near-infrared (NIR) region are prerequisites for expanding current monitoring, imaging, and optical communication capabilities. Herein, we demonstrate photodetectors constructed by OIHP and an organic bulk heterojunction (BHJ) consisting of a low-bandgap nonfullerene and polymer, which achieve broadband response spectra up to 1 μm with a highest external quantum efficiency of approximately 54% at 850 nm, an ultrafast response speed of 5.6 ns and a linear dynamic range (LDR) of 191 dB. High sensitivity, ultrafast speed and a large LDR are preeminent prerequisites for the practical application of photodetectors. Encouragingly, due to the high-dynamic-range imaging capacity, high-quality visible-NIR actual imaging is achieved by employing the OIHP photodetectors. We believe that state-of-the-art OIHP photodetectors can accelerate the translation of solution-processed photodetector applications from the laboratory to the imaging market.
关键词： Organic-inorganic hybrid perovskite,ultrafast response,photodetectors,high-dynamic-range imaging,broadband response,near-infrared
更新于2025-09-19 17:13:59
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Laser-generated focused ultrasound transmitters with frequency-tuned outputs over sub-10-MHz range
摘要： Previous laser-generated focused ultrasound (LGFU) systems have been operated with >15 MHz frequency, allowing for high spatial precision (<100 lm). However, they have been limited only to proximal biomedical applications ex vivo with treatment depths smaller than 10 mm from the lens surface. Although the low-megahertz frequency operation has the advantage of a longer range of therapy, this requires a proper photoacoustic lens made of a nanocomposite coating over a spherically curved substrate whose transmission layer is physically designed for frequency-tuned outputs. This demands a fabrication method that can provide such a nanocomposite structure. We demonstrate photoacoustic lenses operated in an unexplored frequency range of 1–10 MHz, which can simultaneously produce high-amplitude pressure outputs suf?cient for pulsed acoustic cavitation. We physically design a spatially elongated photoacoustic output and then fabricate a transmitter by controlling the density of light-absorbing nanoscale elements in a solution form and by using a replica mold to shape the lens curvature. Our approach is validated by fabricating and characterizing planar transmitters and then applied to focal con?gurations. This offers various possibilities for LGFU-based treatments (e.g., pulsed cavitational therapy such as histotripsy) over the low-megahertz frequency range, which has not been realized by conventional LGFU systems.
关键词： laser-generated focused ultrasound,sub-10-MHz range,frequency-tuned outputs,photoacoustic lenses,acoustic cavitation
更新于2025-09-19 17:13:59
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[IEEE 2019 Photonics North (PN) - Quebec City, QC, Canada (2019.5.21-2019.5.23)] 2019 Photonics North (PN) - Modeling the Incorporation of Microbeads into Concentrator Photovoltaic Systems
摘要： The Range Extensions (RExt) of the High Efficiency Video Coding (HEVC) standard have recently been approved by both ITU-T and ISO/IEC. This set of extensions targets video coding applications in areas including content acquisition, postproduction, contribution, distribution, archiving, medical imaging, still imaging, and screen content. In addition to the functionality of HEVC Version 1, RExt provide support for monochrome, 4:2:2, and 4:4:4 chroma sampling formats as well as increased sample bit depths beyond 10 bits per sample. This extended functionality includes new coding tools with a view to provide additional coding efficiency, greater flexibility, and throughput at high bit depths/rates. Improved lossless, near-lossless, and very high bit-rate coding is also a part of the RExt scope. This paper presents the technical aspects of HEVC RExt, including a discussion of RExt profiles, tools, applications, and provides experimental results for a performance comparison with previous relevant coding technology. When compared with the High 4:4:4 Predictive Profile of H.264/Advanced Video Coding (AVC), the corresponding HEVC 4:4:4 RExt profile provides up to ～25%, ～32%, and ～36% average bit-rate reduction at the same PSNR quality level for intra, random access, and low delay configurations, respectively.
关键词： extensions (RExt),range MPEG-H,compression,High Efficiency Video Coding (HEVC),H.265,video standards
更新于2025-09-19 17:13:59
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Hybrid Transversea??Longitudinal Modes for High Figurea??ofa??Merit Localized Plasmonic Refractometric Sensing in the Visible Spectrum
摘要： The nanoscale confinement of plasmonic fields, coupled with their high susceptibility to refractive index changes, makes localized surface plasmons (LSPs) an excellent platform for rapid and label-free sensing. However, the small spatial overlap of the LSP fields with the adsorbed analyte dictates the sensitivity and figure of merit (FOM) of LSP-based sensing. The linear dependence of sensitivity on resonance wavelength, coupled with the dependence of FOM on the achievable resonance Q factor, leads to a sensitivity of ≈100–300 nm per RIU and FOM < 5 for gold-based LSP resonance in the visible range. This presents a dilemma for the realization of a practical sensing platform that requires high sensitivity and high FOM in the visible spectrum. Higher sensitivity and resonance Q factor can be achieved with a larger interaction volume between the plasmonic field and the analyte. This work explores a hybrid mode resulting from an interaction between transverse LSP and longitudinal Fabry–Perot (FP) modes, capable of improving the sensitivity and FOM simultaneously. This hybrid mode is demonstrated in tall v-shaped split ring resonator structures, fabricated via seedless pulsed gold electrodeposition, with FOM of ≈24 in the visible range.
关键词： plasmonics,sensing,visible range,nanofabrication,seedless electrodeposition
更新于2025-09-19 17:13:59