- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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GWDWT-FCM: Change Detection in SAR Images Using Adaptive Discrete Wavelet Transform with Fuzzy C-Mean Clustering
摘要： Change detection in remote sensing images turns out to play a significant role for the preceding years. Change detection in synthetic aperture radar (SAR) images comprises certain complications owing to the reality that it endures from the existence of the speckle noise. Hence, to overcome this limitation, this paper intends to develop an improved model for detecting the changes in SAR image. In this model, two SAR images captivated at varied times will be considered as the input for the change detection process. Initially, discrete wavelet transform (DWT) is employed for image fusion, where the coefficients are optimized using improved grey wolf optimization (GWO) called adaptive GWO (AGWO) algorithm. Finally, the fused images after inverse transform are clustered using fuzzy C-means (FCM) clustering technique and a similarity measure is performed among the segmented image and ground truth image. With the use of all these technologies, the proposed model is termed as adaptive grey wolf-based DWT with FCM (AGWDWT-FCM). The similarity measures analyze the relevant performance measures such as accuracy, specificity and F1 score. Moreover, the performance of the AGWDWT-FCM in change detection model is compared to other conventional models, and the improvement is noted.
关键词： Filter coefficient,Adaptive discrete wavelet transform,Grey wolf optimization,Synthetic aperture radar,Fuzzy C-means clustering
更新于2025-09-23 15:21:21
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SAR Slow Moving Target Imaging Based on Over-Sampling Smooth Algorithm
摘要： A novel Synthetic aperture radar (SAR) signal processing technique has been proposed which re-focused slow moving targets based on phase retrieval algorithm. After theoretical derivation, we can get that the raw data Fourier magnitude of slow moving targets is approximate to the stationary ones in the SAR system. By applying the Fourier magnitude of received data to phase retrieval algorithms, the blur and defocusing effect caused by the moving of the targets can be eliminated. The simulated results demonstrate the validity of this algorithm.
关键词： Over-sampling smooth,Slow moving target imaging,Synthetic aperture radar,Phase retrieval
更新于2025-09-23 15:21:21
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Estimation and Removal of Strong Range Ambiguities in Multistatic Synthetic Aperture Radar With Multiple Elevation Beams
摘要： Bistatic and multistatic synthetic aperture radar (SAR) can greatly improve system performance in various aspects, especially in achieving high-resolution wide-swath (HRWS) images. However, the specific system structure may lead to a higher degree of range ambiguities. This letter studies the structure of multistatic multiple elevation beams (MMEB) system which achieves HRWS images with the drawback of more serious range ambiguities compared with the conventional SAR which must be suppressed to get an acceptable system performance. The character that the receivers form, a prospective distributed multichannel system in azimuth, can give a guide in estimating the strong range ambiguities and remove them. An innovative method in estimating and removing (not just smearing) the strong range ambiguities based on this character is proposed. Theoretical analysis and experimental results show the effectiveness of the method. The proposed method considerably improves the range ambiguous performance of the MMEB system without using digital beamforming or pulse coding and makes full use of the system character, and thus improves the applicability of the system.
关键词： multistatic multiple elevation beams (MMEB),high-resolution wide-swath (HRWS),range ambiguities,Bistatic and multistatic,synthetic aperture radar (SAR)
更新于2025-09-23 15:21:21
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A Domain Decomposition Finite Element Method for Modeling Electromagnetic Scattering from Rough Sea Surfaces with Emphasis on Near-Forward Scattering
摘要： A high fidelity full-wave simulator is presented to perform numerical experiments for rough sea scattering problem by considering different polarizations, frequencies, grazing angles, wind speeds and sea surface spectra. The simulator is based on a novel Finite Element Domain Decomposition (FEDD) method for solving the problem of two dimensional electromagnetic scattering over one-dimensional sea surface. This non-iterative method partitions the computational domain into a number of overlapping subdomains and solves each domain individually by employing the Locally-Conformal Perfectly Matched Layer (LC-PML) at the truncation boundaries. LC-PML has a unique feature such that it can be applied to irregular domains on the contrary to standard PML methods, and hence inspired the birth of FEDD. The FEDD method is used at each Monte Carlo realization corresponding to a sample from random rough surfaces, and decreases the computational load especially for electrically-large problems. The accuracy and computational efficiency of the method is investigated through several simulations. Using the FEDD method, the statistical behavior of the bistatic Radar Cross Section (RCS) is obtained for both horizontal and vertical polarizations. A special emphasis is given to forward-scattered RCS and the mean reflection coefficient for sea surface especially at low grazing angles, and it is shown that the simulator produces results in agreement with the Ament and Miller-Brown approximations, and experimental data, proving the reliability of the simulation approach. The results are also compared with the standard finite element method and method of moments. Rough sea surfaces are created by using both Pierson-Moskowitz and Elfouhaily spectra.
关键词： Locally-Conformal Perfectly Matched Layer (PML),forward scattering,sea surface,Domain decomposition,Monte Carlo,rough surface scattering,Finite Element Method (FEM),propagation,reflection coefficient,bistatic Radar Cross Section (RCS),multipath
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Incorporating Incidence Angle Variation into Sar Image Segmentation
摘要： We present a new approach for incorporating incidence angle derived synthetic aperture radar (SAR) brightness variation directly into SAR image analysis. This approach is unique in that the incidence angle dependency is modeled explicitly into the probability density function rather than an image-wide pre-processing ‘correction’. It can then be used for supervised and unsupervised image analysis, and is notably able to account for a different dependency rate for each class. This has potential benefits for wide-swath SAR imagery over flat areas and ocean, wide angled airborne and UAV based SAR data, connecting narrow-beam SAR images at different acquisition angles, as well as land-based analysis with local topographic terrain angles. An initial example demonstrates unsupervised image segmentation applied to sea ice mapping for meteorological services and climate science, and is compared to the same algorithm without the incidence angle modeling.
关键词： Terrain Correction,Sentinel-1,Wide-swath imagery,Synthetic Aperture Radar,Incidence Angle Correction
更新于2025-09-23 15:21:21
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Low Complexity Algorithm for Range-Point Migration-Based Human Body Imaging for Multistatic UWB Radars
摘要： High-resolution, short-range sensors that can be applied in optically challenging environments (e.g., in the presence of clouds, fog, and/or dark smog) are in high demand for various applications. Ultrawideband radar is a promising sensor that is suitable for short-range surveillance or watching sensors. Range-point migration (RPM) has been recently established as a promising imaging approach to achieve accurate and real-time 3-D imaging. However, when objects with many scattering points are dealt with, such as a human body, RPM suffers from high computational costs. In this letter, we propose an algorithm with a lower complexity for an RPM-based 3-D imaging method by introducing a sampling-based scattering center extraction with a simpli?ed evaluation function, in which an ef?cient sample pattern is provided by a golden ratio. The results from a ?nite-difference time-domain-based numerical test, which introduces a realistic human body object, demonstrate that our proposed method remarkably reduces the computational cost without sacri?cing the reconstruction accuracy.
关键词： ultrawideband (UWB) radar,short-range sensor,multistatic observation model,3-D imaging,range-point migration (RPM)
更新于2025-09-23 15:21:21
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - Additive Manufactured Antenna in Mixed Material Technology for 24 GHz FMCW Miniaturized Radar
摘要： A 24 GHz antenna design for miniaturized FMCW radar is presented. The antenna was manufactured with additive manufacturing technology at TNO. The characterization of the polymer material used in the fabrication was carried out and the measurement results of the antenna are presented in this work. A good agreement between simulations and measurements was achieved.
关键词： 3D printing technology,FMCW,radar on chip
更新于2025-09-23 15:21:21
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Distance-Resolving Raman Radar Based on a Time-Correlated CMOS Single-Photon Avalanche Diode Line Sensor
摘要： Remote Raman spectroscopy is widely used to detect minerals, explosives and air pollution, for example. One of its main problems, however, is background radiation that is caused by ambient light and sample fluorescence. We present here, to the best of our knowledge, the first time a distance-resolving Raman radar device that is based on an adjustable, time-correlated complementary metal-oxide-semiconductor (CMOS) single-photon avalanche diode line sensor which can measure the location of the target sample simultaneously with the normal stand-off spectrometer operation and suppress the background radiation dramatically by means of sub-nanosecond time gating. A distance resolution of 3.75 cm could be verified simultaneously during normal spectrometer operation and Raman spectra of titanium dioxide were distinguished by this system at distances of 250 cm and 100 cm with illumination intensities of the background of 250 lux and 7600 lux, respectively. In addition, the major Raman peaks of olive oil, which has a fluorescence-to-Raman signal ratio of 33 and a fluorescence lifetime of 2.5 ns, were distinguished at a distance of 30 cm with a 250 lux background illumination intensity. We believe that this kind of time-correlated CMOS single-photon avalanche diode sensor could pave the way for new compact distance-resolving Raman radars for application where distance information within a range of several metres is needed at the same time as a Raman spectrum.
关键词： time-correlated single photon counting (TCSPC),remote Raman spectroscopy,CMOS single-photon avalanche diode (SPAD),time interval measurement,distance-resolving Raman radar,stand-off Raman spectrometer
更新于2025-09-23 15:21:21
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - Target Localization Using MIMO-Monopulse: Application on 79 GHz FMCW Automotive Radar
摘要： A novel target azimuth estimation algorithm called "MIMO-Monopulse" is proposed by combining monopulse approach with multiple-input multiple-output (MIMO) radar. Chebyshev and Zolotarev weighting are applied to synthesis sum and difference pattern of MIMO-monopulse. A new visualization method for monopulse ratio is discussed. Finally, the proposed algorithm is veri?ed successfully by processing real data from a 79 GHz FMCW automotive radar.
关键词： DoA,monopulse,automotive radar,target angle estimation,FMCW,MIMO
更新于2025-09-23 15:21:21
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - A UAV Airborne Passive Digital Radar for Aerial Surveillance
摘要： This paper presents a detailed overview of an experimental passive radar payload developed by ONERA the French Aerospace Lab., which improves the performances of VHF passive radar by using Unmanned Aerial Vehicle (UAV) as support of the receiver. This article highlights the passive radar design which is based on techniques inspired from modern digital receivers combining front-end digitizer and FPGA-based real time data signal processing.
关键词： aerial surveillance,front-end digitizer,passive detection,digital radar,unmanned aerial vehicles
更新于2025-09-23 15:21:21