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- 实验方案
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[IEEE 2018 China International SAR Symposium (CISS) - Shanghai (2018.10.10-2018.10.12)] 2018 China International SAR Symposium (CISS) - A Fast Target Detection Method for SAR Image Based on Electromagnetic Characteristics
摘要： Target detection for remote sensing images which contain optical images and radar images has attracted lots of relative researchers. With the development of deep learning, target detection for optical images has been developing towards high accuracy and real-time detection. High resolution optical images reflect geometric features of the object. Unlike optical images, SAR images reflect the electromagnetic characteristics of the target, so the SAR image detection which uses optical image detection algorithm will lead to weak detection performance. This paper studies a fast target detection algorithm for SAR images which fused electromagnetic characteristics and geometric features through support vector machine. The algorithm is based on the Faster R-CNN framework enabling nearly cost-free target detection.
关键词： real-time detection,scattering center model,electromagnetic characteristics,Faster R-CNN,target detection
更新于2025-09-23 15:22:29
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Micromagnetic Modeling of All-Optical Switching
摘要： The control of the magnetization at the microscale by pure optical means is fundamentally interesting and promises faster speeds for data storage devices. Although several experiments have shown that it is possible to locally reverse the magnetization of a ferromagnetic system by means of laser pulses, a completely theoretical description of these all-optical switching (AOS) processes is still lacking. Here, we develop an advanced micromagnetic solver that is applied to the numerical study of the AOS. The solver is based on the Landau–Lifshitz–Bloch equation that governs the dynamics of the magnetization coupled the microscopic three-temperature model, which describes the temporal evolution of the temperatures of the subsystems as caused by laser heating. The helicity-dependent magnetization switching is evaluated by a magnetooptical effective field caused by the inverse Faraday effect when a circularly polarized laser is applied to the sample. All the other usual terms of a full micromagnetic model are included (exchange, anisotropy, and Dzyaloshinskii–Moriya interaction). As a test, the model is used to describe the local magnetization switching of thin-film samples with high perpendicular anisotropy. The results are in a good agreement with available experimental observations.
关键词： Landau–Lifshitz–Bloch (LLB) equation,three temperatures model (3TM),inverse Faraday effect (IFE),micromagnetism,All-optical switching (AOS)
更新于2025-09-23 15:22:29
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[IEEE 2018 Wave Electronics and its Application in Information and Telecommunication Systems (WECONF) - Saint-Petersburg, Russia (2018.11.26-2018.11.30)] 2018 Wave Electronics and its Application in Information and Telecommunication Systems (WECONF) - Spectral Masking in MFCC Calculation for Noisy Speech
摘要： To increase noise immunity of the MFCC (mel-frequency cepstral coefficients) widely used for voice signal parametrisation it is suggested to use a psychoacoustic model of frequency masking. Additionally, taking into account the formation mechanism of the formant regions in the voice signal spectrum it is suggested to influence the spectral samples corresponding to multiple harmonics of the fundamental tone. The modified algorithm is investigated on the basis of the single word recognition system adapted for MFCC voice signal parametrisation only. The positive effect of using proposed additional voice signal transformation in the parametrisation algorithm is shown.
关键词： psychoacoustic model,voice signal,parametrisation,MFCC
更新于2025-09-23 15:22:29
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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 - Relationship Between Bistatic Radar Scattering Cross Sections and GPS Reflectometry Delay-Doppler Maps Over Vegetated Land in Support of Soil Moisture Retrieval
摘要： This paper presents the application of a coherent bistatic radar scattering model from vegetated terrains and the extension of the model to circularly polarized incident wave cases for GNSS signals. It will then present an analysis relating the bistatic scattering Radar Cross Sections (RCS) of vegetated land cover to the customary Delay Doppler Maps (DDMs) resulting, e.g., from GNSS reflectometry (GNSS-R) observations. This step is key in being able to use GNSS-R data in soil moisture retrieval algorithms. While some analyses exist for this purpose for scattering from sea surface, such analysis has not been carried out specifically for vegetated land surface. The proposed model and methods are envisioned to be applied to the airborne GNSS Reflectometer Instrument for Bistatic SAR (GRIBSAR) project currently under development, as well as to the CYGNSS mission.
关键词： GRIBSAR,Coherent bistatic radar scattering model,GNSS-R,RCS,Delay Doppler Map
更新于2025-09-23 15:22:29
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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 - A Novel Approach to Select Anchor Pixels in Sebal Model by Using Inputs from SAR Images
摘要： The proper selection of anchor pixels (hot and cold pixels) for calculating the sensible heat flux (H) in SEBAL (Surface Energy Balance Algorithm for Land) is a critical aspect to be considered. The current study proposes a novel method to select the cold and hot pixels using the soil moisture measurements derived from the SAR images. The Water cloud Model (WCM) derived soil moisture values combined with NDVI and Land Surface Temperature values were used to locate the anchor pixels in the current study. The results confirmed that the capability of SAR images combined with optical images will help in the appropriate selection of anchor pixels. The ET values obtained in the study showed good agreement with the ground conditions.
关键词： Landsat8,Hot and Cold Pixels,Water Cloud Model,Sentinel1A,SEBAL
更新于2025-09-23 15:22:29
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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 - A New Model for P-Band Pol-InSAR Based on Gamma Distribution
摘要： This work proposes a forest model based on Gamma distribution to better describe the forest vertical structure for height inversion using P-band polarimetric synthetic aperture radar interferometry (Pol-InSAR) data. The proposed model takes into account the forest vertical heterogeneity and asymmetry, to which volume interferometric coherence is sensitive. The interferometric coherence associated with a volume where the vertical backscattered power varies following a Gamma distribution is derived. The effect of scattering center height standard deviation and mean elevation to the volume interferometric coherence is investigated. Finally, the strategy of multi-baseline on the proposed model for forest height inversion using P-band Pol-InSAR data is proposed.
关键词： P-band Pol-InSAR,forest model,Gamma distribution,vertical heterogeneity
更新于2025-09-23 15:22:29
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[IEEE 2018 China International SAR Symposium (CISS) - Shanghai (2018.10.10-2018.10.12)] 2018 China International SAR Symposium (CISS) - Two Dimensional Image Formation of Interrupted FMCW SAR Through Spectral Analysis
摘要： Most of spaceborne Synthetic Aperture Radar (SAR) systems are based on pulsed mode of operation. Such systems are quite expensive and large sized. Frequency Modulated Continuous Wave (FMCW) based SAR is a light weight and less expensive solution, but the disadvantage is that it requires two antennas – one for transmit and other for receive. Interrupted-FMCW is a recently proposed idea for spaceborne SAR that uses a single antenna for transmission and reception. The main problem of this approach is discontinuity of data in azimuth. This paper proposes a two-dimensional image formation algorithm that uses spectral analysis methods for processing of interrupted-FMCW SAR data. The algorithm has been tested on simulated point target data as well as on a real FMCW data, and the results have been discussed.
关键词： spectral analysis,synthetic aperture radar,interrupted-FMCW,all-pole model,image formation
更新于2025-09-23 15:22:29
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A Surface Potential Based Model for Dual Gate Bilayer Graphene Field Effect Transistor Including the Capacitive Effects
摘要： In this work, a surface potential modeling approach has been proposed to model dual gate, bilayer graphene field effect transistor. The equivalent capacitive network of GFET has been improved considering the quantum capacitance effect for each layer and inter-layer capacitances. Surface potentials of both layers are determined analytically from equivalent capacitive network. The explicit expression of drain to source current is established from drift-diffusion transport mechanism using the surface potentials of the layers. The drain current characteristics and transfer characteristics of the developed model shows good agreement with the experimental results in literatures. The small signal parameters of intrinsic graphene transistor i.e. output conductance (gds), trans-conductance (gm), gate to drain capacitance (Cgd) and gate to source capacitance (Cgs) have been derived and finally, the cut-off frequency is determined for the developed model. The model is compared with reported experimental data using Normalised Root Mean Square Error (NRMSE) metric and it shows less than 16% NRMSE. A Verilog-A code has been developed for this model and a single ended frequency doubler has been designed in Cadence design environment using this Verilog-A model.
关键词： model,Field-effect transistor (FET),Verilog-A,Graphene,surface potential,frequency doubler.
更新于2025-09-23 15:22:29
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An Efficient and Robust Iris Segmentation Algorithm Using Deep Learning
摘要： Iris segmentation is a critical step in the entire iris recognition procedure. Most of the state-of-the-art iris segmentation algorithms are based on edge information. However, a large number of noisy edge points detected by a normal edge-based detector in an image with specular reflection or other obstacles will mislead the pupillary boundary and limbus boundary localization. In this paper, we present a combination method of learning-based and edge-based algorithms for iris segmentation. A well-designed Faster R-CNN with only six layers is built to locate and classify the eye. With the bounding box found by Faster R-CNN, the pupillary region is located using a Gaussian mixture model. Then, the circular boundary of the pupillary region is fit according to five key boundary points. A boundary point selection algorithm is used to find the boundary points of the limbus, and the circular boundary of the limbus is constructed using these boundary points. Experimental results showed that the proposed iris segmentation method achieved 95.49% accuracy on the challenging CASIA-Iris-Thousand database.
关键词： Iris segmentation,Faster R-CNN,Gaussian mixture model,Boundary point selection,Deep learning
更新于2025-09-23 15:22:29
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Evaluation of Ground Surface Models Derived from Unmanned Aerial Systems with Digital Aerial Photogrammetry in a Disturbed Conifer Forest
摘要： Detailed vertical forest structure information can be remotely sensed by combining technologies of unmanned aerial systems (UAS) and digital aerial photogrammetry (DAP). A key limitation in the application of DAP methods, however, is the inability to produce accurate digital elevation models (DEM) in areas of dense vegetation. This study investigates the terrain modeling potential of UAS-DAP methods within a temperate conifer forest in British Columbia, Canada. UAS-acquired images were photogrammetrically processed to produce high-resolution DAP point clouds. To evaluate the terrain modeling ability of DAP, first, a sensitivity analysis was conducted to estimate optimal parameters of three ground-point classification algorithms designed for airborne laser scanning (ALS). Algorithms tested include progressive triangulated irregular network (TIN) densification (PTD), hierarchical robust interpolation (HRI) and simple progressive morphological filtering (SMRF). Points were classified as ground from the ALS and served as ground-truth data to which UAS-DAP derived DEMs were compared. The proportion of area with root mean square error (RMSE) <1.5 m were 56.5%, 51.6% and 52.3% for the PTD, HRI and SMRF methods respectively. To assess the influence of terrain slope and canopy cover, error values of DAP-DEMs produced using optimal parameters were compared to stratified classes of canopy cover and slope generated from ALS point clouds. Results indicate that canopy cover was approximately three times more influential on RMSE than terrain slope.
关键词： Structure from Motion (SfM),point cloud classification,unmanned aerial systems (UAS),digital elevation model (DEM)
更新于2025-09-23 15:22:29