- 标题
- 摘要
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- 实验方案
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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 - Parametrization of a Dielectric Mixture Model to Retrieve Soil Moisture at Field Scale Using Sentinel-1 Data and in Situ Soil Moisture Measurements
摘要： In the framework of the H2020 APOLLO project a significant focus has been put on the use of high resolution satellite based products to serve small farmers in their agricultural practices. This paper presents first results achieved by using Sentinel-1 Synthetic Aperture Radar (SAR) data as input to a semi-empirical soil moisture (SM) retrieval model based on an algorithm originally developed for ERS SAR data and successively modified to handle ENVISAT ASAR acquisitions. In this work the model has been adapted to Sentinel-1 images and calibrated by using ground measurements taken in two test sites characterized by bare soil and cotton cultivation, aiming at testing its capability to represent the SM behavior at different stages of the vegetation cycle. The model performance has been assessed through the correlation R and root mean squared error (RMSE) between in situ and satellite retrieved SM data. Very good results have been achieved for bare soil (R>0.8, RMSE<0.04 m3m-3); however, the model performed worse in the cotton fields (R<0.6, RMSE>0.08 m3m-3).
关键词： Soil moisture,SAR,Sentinel-1,agricultural fields
更新于2025-09-04 15:30:14
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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 - Semi-Automatic Deforestation Detection Algorithm with PALSAR-2/ScanSAR HH/HV Polarizations
摘要： A preliminary version of the semi-automatic deforestation detection algorithm was developed for the JJ-FAST system, which monitors deforestation and forest changes in tropical regions for approximately every 1.5 months and covers 77 countries. PALSAR-2/ScanSAR HH, HV, HH and HV ratio were used to detect various deforestation stages. Multi-temporal data were used to suppress the effect of seasonality and rainfall. Moreover, the deforestation accuracies for the active deforestation spots in Brazil and Peru were estimated. The user’s accuracies achieved as 80.5% in the dry season, but these decreased to 11.1% in the rainy season.
关键词： polarization,L-and SAR,Forest monitoring
更新于2025-09-04 15:30:14
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NOVEL DATA ACQUISITION METHOD FOR INTERFERENCE SUPPRESSION IN DUAL-CHANNEL SAR
摘要： Various interference sources either intentional or unintentional can mask the synthetic aperture radar (SAR) signals and cause image degradation. With a novel data acquisition mode, a new method based on dual-channel SAR is applied to suppress the interference. Using the received dual-channel data, the two-dimensional location of the interference source can be estimated and then the interference can be removed via a Two-Channel-Cancelation method. By establishing a linear model of the interference-removed signal, the SAR image is reconstructed based on compressed sensing (CS) theory. Our method requires only a minor change to the traditional SAR system hardware while obtains a higher resolution. Simulation results are shown to demonstrate the validity of the proposed method.
关键词： interference suppression,SAR,dual-channel,data acquisition,compressed sensing
更新于2025-09-04 15:30:14
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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 - Automatic Coregistration of SAR and Optical Images Exploiting Complementary Geometry and Mutual Information
摘要： Image coregistration aims at stacking two or multiple images in a way such that, for each image, the same pixel corresponds to the same point of the target scene (possibly with sub-pixel accuracy). We can distinguish two families of image coregistration problems, basically depending on if the images to be coregistered are taken by sensors of the same or different type (e.g., sensing different wavelenghts), and with similar or different illumination and acquisition geometries (e.g. different sun illumination conditions and/or different acquisition incidence angles).Whilst the first type of image coregistration is well established, multimodal coregistration is not yet well founded and due to difficulty of finding correspondences between the images (tie points) in a robust way, and the available approaches often recur to manual assistance. The multimodal image coregistration technique proposed in this work overcomes the problems due to differences in radiometries and in geometries by exploiting two main concepts: complementary geometry information between the images to be coregistered, and mutual information (or entropy) as similarity metric. The method focuses on coregistration of very high resolution synthetic aperture radar (SAR) and optical images, but the approach is of general validity. The tests performed on real very high resolution optical and SAR data confirm the validity of the method.
关键词： SAR feature extraction,image coregistration,mutual information,bundle adjustment,multimodal image coregistration
更新于2025-09-04 15:30:14
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[IEEE 2018 China International SAR Symposium (CISS) - Shanghai, China (2018.10.10-2018.10.12)] 2018 China International SAR Symposium (CISS) - A New Method of Phase-Perturbed LFM Chirp Signals for SAR ECCM
摘要： The active coherent jamming based on Digital Radio Frequency Memory (DRFM) is an effective method of jamming for synthetic aperture radar (SAR). The traditional linear frequency modulated signal (LFM) signal synthetic aperture radar has poor capability of counting active coherent jamming. In this paper, a new SAR signal based on phase- perturbed LFM (PPLFM) signal was proposed to improve the ability of radar to resist active coherent jamming. First, the design method of PPLFM signal is presented, after which the disturbance amplitude matrix is optimized. Then the electronic counter countermeasures (ECCM) performance and imaging performance of the PPLFM signal are analyzed with different disturbance parameters. Finally, the ability to suppress false target jamming and frequency shift jamming is compared with the LFM signal. Simulation results show that the PPLFM signal can effectively suppress the active coherent jamming compared with the LFM signal.
关键词： Electronic Counter Countermeasures (ECCM),Pulse diversity,Synthetic Aperture Radar (SAR)
更新于2025-09-04 15:30:14
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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 - Sea Ice Classification with Convolutional Neural Networks Using Sentinel-L Scansar Images
摘要： In this paper, the Sentinel-1 ScanSAR IR GRD products are used for sea ice mapping using convolutional neural networks (CNN). The sea and ice are classified as 2 types and 4 types respectively according to their SAR image textures. They are smooth sea, rough sea, granular ice, massive ice, smooth ice and striped ice. The Sentinel-1 SAR images are firstly pre-processed using ESA SNAP software. Then the classes are interpreted manually for chip preparation and annotations. Chips with 3 spatial scales (32x32, 64x64, 128x128) are used for training input of the CNN. The trained CNN is then used for generation of sea ice map from the ScanSAR image. The results are promising. Further work is still going on.
关键词： sea ice,classification,convolutional neural networks,deep learning,SAR
更新于2025-09-04 15:30:14
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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 - Spherical Harmonic-Based Spectral Projection Model for Holographic SAR Imaging
摘要： A spectral projection model which is based on spherical harmonics is developed for three-dimensional holographic SAR imaging. The addition theorem for spherical harmonics is used for describing the SAR measurement process as a projection of a source spectral vector onto an observation spectral vector. The source vector for a particular scatterer is determined by the spherical coordinates of that scatterer. The dimension of the source vector is determined by the largest dimension of the SAR viewing area. The observation vectors are similarly defined in terms of the spherical coordinates of each measurement point along the SAR flight path. By separating the source and observation terms in the addition theorem, the contribution from each scatterer to each specific SAR measurement is described as the projection of the source spectral vector onto the observation spectral vector. Simulations are used to investigate the spectral properties of a variety of source distributions and SAR flight paths. Sample holographic images are simulated using this spectral projection model.
关键词： addition theorem,Holographic SAR,spectral projection model,spherical harmonics
更新于2025-09-04 15:30:14
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On the Use of Cross-Correlation between Volume Scattering and Helix Scattering from Polarimetric SAR Data for the Improvement of Ship Detection
摘要： Synthetic Aperture Radar (SAR) ship detection is an important maritime application. However, azimuth ambiguities caused by the finite sampling of the Doppler spectrum are often visible in SAR images and are always mistaken as ships by classic detection techniques, like the Constant False Alarm Rate (CFAR). It is known that radar targets and azimuth ambiguities have different characteristics in polarimetric SAR (PolSAR) data, i.e., first ambiguities usually have strong odd- or double-bounce scattering and the maximum amplitude of the first ambiguity in SHV is always considerably smaller than that of the corresponding target for zero or high velocity. On the basis of this characteristics, this paper finds that first ambiguities usually have low volume scattering power relative to ships and almost have no helix scattering by Yamaguchi decomposition. But some residual ambiguities still exit in the volume scattering power and have similar scattering intensity to small ships, and some parts of a ship also have zero helix scattering owing to some physical factors (e.g., ship structure, radar incidence angle, etc.). Thus, for high-precision ship detection, a new ship detection method based on cross-correlation between the volume and helix scattering mechanisms derived from Yamaguchi decomposition is proposed to avoid false alarms caused by azimuth ambiguities and enhance Target-to-Clutter Ratio (TCR) for improving the miss detection rate of small ships. By experiments, it is proved that our method can work effectively and has high detection accuracy.
关键词： CFAR,azimuth ambiguity,polarimetric SAR,ship detection,Yamaguchi decomposition
更新于2025-09-04 15:30:14