- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A Markovian Approach to Unsupervised Change Detection with Multiresolution and Multimodality SAR Data
摘要： In the framework of synthetic aperture radar (SAR) systems, current satellite missions make it possible to acquire images at very high and multiple spatial resolutions with short revisit times. This scenario conveys a remarkable potential in applications to, for instance, environmental monitoring and natural disaster recovery. In this context, data fusion and change detection methodologies play major roles. This paper proposes an unsupervised change detection algorithm for the challenging case of multimodal SAR data collected by sensors operating at multiple spatial resolutions. The method is based on Markovian probabilistic graphical models, graph cuts, linear mixtures, generalized Gaussian distributions, Gram–Charlier approximations, maximum likelihood and minimum mean squared error estimation. It bene?ts from the SAR images acquired at multiple spatial resolutions and with possibly different modalities on the considered acquisition times to generate an output change map at the ?nest observed resolution. This is accomplished by modeling the statistics of the data at the various spatial scales through appropriate generalized Gaussian distributions and by iteratively estimating a set of virtual images that are de?ned on the pixel grid at the ?nest resolution and would be collected if all the sensors could work at that resolution. A Markov random ?eld framework is adopted to address the detection problem by de?ning an appropriate multimodal energy function that is minimized using graph cuts.
关键词： Markov random ?elds (MRF),maximum likelihood (ML) estimation,synthetic aperture radar (SAR),Gram–Charlier approximation,multiresolution data fusion,multimodality data fusion,graph cuts,minimum mean squared error (MMSE) estimation,generalized Gaussian
更新于2025-09-10 09:29:36
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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 - Land Subsidence Monitoring by Integrating PSI and Geodetic Deformation Measurements
摘要： Leveling provides vertical ground deformation and Global Positioning System (GPS) provides three-dimensional (3-D) deformation with subcentimeter accuracy level, but these measurements are point observations. In order to achieve a high spatial resolution, synthetic aperture radar (SAR) is an effective approach. In particular, Persistent Scatterers Interferometry (PSI) can accurately measure wide range of land subsidence by using multi-temporal SAR images. Thus, in this paper, we will merge the results from PSI and geodetic deformation measurements (GPS and leveling) to estimate the 3-D displacement velocities of Kansai International Airport with high spatial resolution. We apply the least square (LS) approach to combine the interpolated result from GPS and leveling, and estimated results by PSI from SAR images observed on ascending- and descending-orbits. Finally, we compared the estimated results with leveling survey data. The root mean squared error (RMSE) was 18 mm/year, and it was found that the fusion of the results from PSI and geodetic deformation measurements is effective for land subsidence monitoring.
关键词： GPS,land subsidence,PSI,leveling,synthetic aperture radar (SAR)
更新于2025-09-10 09:29:36
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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 - A Classification Method for Polsar Images using SLIC Superpixel Segmentation and Deep Convolution Neural Network
摘要： Deep convolution neural networks (DCNN) have been successfully introduced in the field of Polarimetric SAR image classification. However, the commonly used DCNN will classify each pixel in the image and neglect the fact that neighboring pixels may have similar intensity. Besides, the fixed size input in DCNN cannot be well adopted in remote sensing image which includes a great deal of different-scale information. Thus, superpixel segmentation (SS) and the input pyramid are introduced in this paper to improve the performance of DCNN. The former will guide the DCNN to classify superpixel instead of single pixel and the latter will include different-scale information around the pixel. Experiments carried out on two scenes of ALOS-2 PALSAR-2 POLSAR images demonstrate that the introduced technic can help DCNN achieve good accuracy and smooth boundary adherence with highly efficiency.
关键词： superpixel segmentation,convolution neural network,Polarimetric synthetic aperture radar
更新于2025-09-10 09:29:36
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Bistatic ISAR Imaging for Non-Uniformly Rotating Targets
摘要： When a target undergoes non-uniform rotational motion (RM), conventional motion compensation (MOCOM) approaches for monostatic inverse synthetic aperture radar (ISAR) systems fail to correct the non-uniform RM error in bistatic radar systems; this failure is caused by nonlinear phase relationships between scatterers in bistatic ISAR (Bi-ISAR) systems. To address this problem, in this paper, we propose a new MOCOM framework for Bi-ISAR imaging of non-uniformly rotating targets. In the proposed method, a newly devised correction is performed to ensure successful RM compensation, followed by translational motion compensation (TMC). Because the phase relationships of the scatterers become virtually linear after this correction, non-uniform RM can be successfully converted into uniform RM. Namely, using the proposed method, translational and rotational motion errors are correctly removed, and focused Bi-ISAR images are obtained even for a target involved in non-uniform RM. Further, for more effective use of Bi-ISAR images, a method to restore sheared Bi-ISAR images is exploited in the proposed framework. In the simulations and experiments, we determined that the proposed method can provide high-quality Bi-ISAR images for non-uniformly rotating targets.
关键词： rotational motion compensation (RMC),Autofocus,rotational motion (RM),motion compensation (MOCOM),bistatic inverse synthetic aperture radar (Bi-ISAR) imaging,non-uniform rotational motion
更新于2025-09-10 09:29:36
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Real-Time Multi-View SAR Imaging Using a Portable Microwave Camera with Arbitrary Movement
摘要： This paper presents the ?rst demonstrator of a portable, multi-view, high-resolution, three-dimensional (3D) and real-time microwave imaging system. The system is based on a recently-developed real-time 3D microwave camera, which performs quasi-monostatic acquisitions, equipped with an optical depth camera providing target surface pro?le information. Additionally, the entire system can be arbitrarily moved along the target performing microwave and depth camera synchronized acquisitions from different views with a twofold purpose, namely; a) enabling a coverage area much larger than that possible with a static imaging system, and b) allowing for incorporation of several tilt angles (or views) to enhance capturing specular re?ection imaging data to improve the overall image quality. At each scanning position, the imaging data from the microwave camera are processed to build a local 3D microwave image. The information is then merged, using recently-proposed techniques for multi-view synthetic aperture imaging, to compose the global image. The synchronized optical camera depth acquisitions enable tracking the entire imager movements so that the position and attitude are known. Moreover, the data acquired by the depth camera are also use to build a complementary 3D outer surface pro?le model of the target, producing a combined and realistic image of the internal and external geometries of the target. Finally, the performance of the combined system is evaluated using several examples related to hidden contraband covered by clothing (i.e., people screening).
关键词： 3D microwave camera,multi-view imaging,synthetic aperture imaging,depth camera
更新于2025-09-10 09:29:36
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All-Directions Through-the-Wall Imaging Using a Small Number of Moving Omnidirectional Bi-Static FMCW Transceivers
摘要： Through-the-wall radar imaging is a powerful tool for mapping buildings’ interiors and hidden objects behind the walls. Through-the-wall imaging systems require large linear arrays of directive antennas to form a large aperture for obtaining images with a high cross-range resolution. However, the low mobility and limited field of view of the conventional systems limit their imaging capability. The concept of all-directions through-the-wall imaging has recently been proposed to enhance the mobility, cross-range resolution, and field of view of the through-the-wall imaging systems. In this technique, the large linear array of directive antennas is replaced by a dense 2-D synthetic array formed by small moving transceivers utilizing omnidirectional antennas. The 2-D synthetic array provides 360° high cross-range resolution images. This paper focuses on the implementation of a system realizing all-directions through-the-wall imaging and measurement results. A bi-static frequency-modulated continuous wave (FMCW) radar system utilizing a simple wireless synchronization scheme and wideband omnidirectional antennas is fabricated and an image formation technique compatible with bi-static FMCW imaging system is presented. Measurement results show that the imaging system can provide 360° high-resolution image of objects and walls in a short time.
关键词： through-the-wall imaging,Bi-static,frequency-modulated continuous wave (FMCW),circular polarization,synthetic aperture,imaging
更新于2025-09-10 09:29:36
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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 - IBIS-ArcSAR: an Innovative Ground-Based SAR System for Slope Monitoring
摘要： In the last decade Ground-Based SAR (GB-SAR) technology has been demonstrated to be one of the most efficient tool for slope monitoring in open pit mines scenarios. However, especially for open pit mines application, one of the relevant limits is the azimuth coverage, being the mine often of elliptical shape. In this context, the IBIS-FM product of IDS GeoRadar company can reach about 80° of horizontal coverage, and can be overcome by IBIS-Rover product that can reach 270° of horizontal coverage but increasing the acquisition time. The recent IBIS-ArcSAR product developed by IDS GeoRadar can overcome these limits, offering a full 360° of horizontal coverage in less than 1 minute of acquisition time, with additional feature of a constant angular resolution. Moreover, by exploiting the new capability of MIMO (Multiple Input Multiple Output) Radar channels, the vertical height or Digital Elevation Model (DEM) of the mine can be reconstructed through simple and computationally fast interferometric processing algorithms, together with an enhanced focusing of 2D SAR Image that is an open issue in Arc-scanning SAR systems.
关键词： Interferometry,Ground-based Synthetic Aperture Radar,Digital Elevation Models,MIMO Radar,Radar Imaging
更新于2025-09-10 09:29:36
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Reference Module in Materials Science and Materials Engineering || Optical Lithography
摘要： Optical lithography is a photon-based technique comprised of projecting, or shadow casting, an image into a photosensitive emulsion (photoresist) coated onto the substrate of choice. Today it is the most widely used lithography process in the manufacturing of nano-electronics by the semiconductor industry, a $400 Billion industry worldwide. Optical lithography’s ubiquitous use is a direct result of its highly parallel nature allowing vast amounts of information (i.e., patterns) to be transferred in a very short time. For example, considering the specification of a modern leading edge scanner (150–300-mm wafers per hour and 40-nm two-dimensional pattern resolution), the pixel throughput can be found to be approximately 1.8T pixels per second. Continual advances in optical lithography capabilities have enabled the computing revolution we have undergone over the past 50 years.
关键词： Nano-electronics,Numerical Aperture (NA),Coherence,Resolution,Photoresist,Depth of Focus (DOF),Optical Lithography,Extreme Ultraviolet (EUV),Semiconductor
更新于2025-09-10 09:29:36
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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 - An Efficient Image Formation Algorithm for Spaceborne Video SAR
摘要： To avoid unnecessary duplication of processing and meet the real-time requirement of video SAR. An image formation algorithm of spaceborne video SAR based on sub-aperture extended chirp scaling processing was proposed in this paper. Firstly the SAR raw data segmentation approach was presented to realize the SAR video frames continuous output. Then the raw data of a video frame was divided to several sub-apertures, after the extended CS processing in the sub-apertures, the frequency sub-bands of sub-apertures were combined to achieve the desired high azimuth resolution video SAR frames. This innovative image formation algorithm can avoid the duplication of processing, so as to improve computation efficiency. Finally, experiments on simulated data show that the proposed algorithm is effective.
关键词： spaceborne video SAR,extended chirp scaling algorithm,data overlap,sub-aperture processing
更新于2025-09-10 09:29:36
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Underlying Topography Estimation Over Forest Areas Using Single-Baseline InSAR Data
摘要： In this paper, a method for digital elevation model (DEM) extraction over forest areas from single-baseline interferometric synthetic aperture radar (InSAR) data is proposed. The main idea of this method is that some backscattering variations which are linked to the geometrical structures of forest occur during the radar acquisition. The time–frequency analysis is used to retrieve these variations by dividing the synthesized SAR image into multiple SAR images in the Fourier domain called sublook images. Then, by interferometry, the sublook images characterized by the same Doppler bandwidth and acquired from spatially separated locations at either end of a baseline are used to estimate the sublook coherences and the above backscattering variations are converted into the variations the number of InSAR of sublook coherences. As a result, observations can be increased. The sublook coherences are then interpreted by the two-layer vegetation scattering model and are assumed to follow a near-linear relationship in the complex plane. The ground phase can then be estimated by linear regression of the sublook coherences. The performance of the proposed method was validated by E-SAR L- and P-band SAR data acquired over coniferous and tropical forests. For the coniferous scenario, the underlying DEM estimated by the proposed method has a root-mean-square error (RMSE) of 4.39 m, which is slightly less accurate than the DEM (with an RMSE of 4.07 m) derived by the polarimetric line-?t (LF) method, but represents a signi?cant improvement in DEM accuracy over the HH InSAR method. For the tropical scenario, the DEMs derived by the proposed method and the polarimetric LF method are closer to the ground surface than those derived by the HH InSAR method, and their mean ground height difference is 0.62 m. The two experiments con?rm that it is feasible to extract a DEM by the proposed method, which has a comparable performance in DEM inversion to the polarimetric LF method and only requires single-polarization InSAR data.
关键词： time–frequency (TF) analysis,underlying topography,two-layer vegetation scattering model,Interferometric synthetic aperture radar (InSAR)
更新于2025-09-10 09:29:36