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A New Synthetic Aperture Radar (SAR) Imaging Method Combining Match Filter Imaging and Image Edge Enhancement

SENSORS 2018年第12期18卷 4133-4133页

作者： Sun, Bing Fang, Chuying Xu, Hailun Gao, Anqi Beihang Univ Sch Elect & Informat Engn Beijing 102200 Peoples R China

In general, synthetic aperture radar (SAR) imaging and image processing are two sequential steps in SAR image processing. Due to the large size of SAR images, most image processing algorithms require image segmentation before processing. However, the existence of speckle noise in SAR images, as well as poor contrast and the uneven distribution of gray values in the same target, make SAR images difficult to segment. In order to facilitate the subsequent processing of SAR images, this paper proposes a new method that combines the back-projection algorithm (BPA) and a first-order gradient operator to enhance the edges of SAR images to overcome image segmentation problems. For complex-valued signals, the gradient operator was applied directly to the imaging process. The experimental results of simulated images and real images validate our proposed method. For the simulated scene, the supervised image segmentation evaluation indexes of our method have more than 1.18%, 11.2% and 11.72% improvement on probabilistic Rand index (PRI), variability index (VI), and global consistency error (GCE). The proposed imaging method will make SAR image segmentation and related applications easier.

关键词： imaging edge detection image segmentation back-projection algorithm differential operation

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BP-Based Matrix Completion for Near-Field MIMO Array Imaging 36

BP-Based Matrix Completion for Near-Field MIMO Array Imaging

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第36届中国控制会议

作者： Liechen Yu Xiongjun Wu National Defense Key Laboratory of Science and Technology on Electromagnetic Scattering The 802 Institute of Shanghai Academy of Space Flight TechnologyThe Eighth Academy of China Aerospace Science and Technology Corporation

ISBN: (纸本)9781538629185

The near-field array-based imaging radar systems have been widely used for concealed weapon detection,medical imaging,***,traditional systems always require a large number of real antenna elements,which increase the cost and complexity of the *** paper firstly introduces an optimization method for near-field MIMO array design referring to the convolution *** antenna elements of the MIMO array are sparse which can obviously decrease the cost and complexity of the *** back-projection（BP） algorithm is usually used for the MIMO radar imaging,which is a time-consuming ***,the paper presents a fast imaging algorithm which combines matrix completion with *** completion is a new technique which can be applied to recover a low-rank matrix from a subset of the matrix *** are provided to demonstrate the performance of the proposed algorithm,which proves that it is an effective way to solve the near-field sparse MIMO array imaging problem in a fast speed.

关键词： Near-field MIMO array back-projection algorithm Matrix completion

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Efficient Global back-projection on an FPGA

Efficient Global Back-Projection on an FPGA

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IEEE International Radar Conference (RadarCon)

作者： Pritsker, Dan Altera Corp San Diego CA USA

ISBN: (纸本)9781479982325

The Global back-projection (GBP) algorithm has been known for use in Synthetic Aperture Radar (SAR) image formation for many years. But, despite many advantages compared to other algorithms, GBP usage is limited. It requires significant computational complexity and consumes more power. This paper presents a high-performance architecture which allows efficient and scalable implementation of the GBP algorithm on a Field Programmable Gate Array (FPGA). Such an architecture is based on a systolic array that performs back-projection in a pipelined way, using parallelism over image pixels and radar pulses. A GBP systolic array is built using specially designed back-projection streaming cores. The cores utilize a floating-point calculation on the FPGA to achieve accurate and high-dynamic range in GBP integration. Results presented herein, show the achieved performance of GBP-based image formation using an FPGA and details the power consumption of the described implementation. Comparison is made to other computational platforms in order to determine advantage for real-time and power constrained SAR applications and platforms.

关键词： Synthetic Aperture Radar SAR back-projection algorithm Image Formation FPGA GPU Floating-Point

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Comparison of SIMO-Based Wavenumber Domain and back-projection Imaging algorithms

Comparison of SIMO-Based Wavenumber Domain and Back-Projecti...

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Asia-Pacific Microwave Conference (APMC)

作者： Liu, Shuang Li, Shiyong Zhao, Guoqiang Sun, Houjun Beijing Inst Technol Beijing Key Lab Millimeter Wave & Terahertz Techn Beijing 100081 Peoples R China

ISBN: (纸本)9781479987672

The single-input multiple-output (SIMO) array based imaging system has been applied for remote sensing and concealed weapon detection. In this paper, comparisons of the back-projection (BP) algorithm and wavenumber domain (omega k) algorithm applied to SIMO imaging are provided both in the near-field case and far-field case. Simulations demonstrate that the BP algorithm performs better in the near-field case. For the wk algorithm, there would appear deviation and slight defocusing of the target due to the Taylor approximation in the near-field case. In the far-field case, the imaging result of BP algorithm is almost identical with that of omega k algorithm but the former would need more operation time.

关键词： single input multiple output (SIMO) wavenumber domain algorithm back-projection algorithm two dimensional imaging

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WIDE-FIELD CIRCULAR SAR IMAGING: AN EMPIRICAL ASSESSMENT OF LAYOVER EFFECTS

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2015年第2期57卷 489-497页

作者： Demirci, Sevket Yigit, Enes Ozdemir, Caner Mersin Univ Dept Elect Elect Engn TR-33343 Ciftlikkoy Mersin Turkey Mersin Univ Vocat Sch Tech Sci TR-33343 Ciftlikkoy Mersin Turkey

In circular synthetic aperture radar (CSAR), targets are usually scanned over the complete azimuthal aperture of 360 degrees. A major challenge inhibiting successful CSAR image production is encountered in two-dimensional imaging of relatively large scenes (i.e. wide-field scenarios). For such cases, the spatially variant radar signature gives rises to image degradations known as layover effects. In this paper, the imaging results for hypothetical and real complex targets using their CSAR data at C band are demonstrated to characterize these effects. In real experiments, a ground-based, outdoor CSAR system is exploited thanks to the circular balcony of a building that provides 270 degrees view of targets. A spherical back-projection algorithm is used to focus near-field data and the reconstructed images are also cleaned out from clutter to more easily visualize the layover artifacts. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:489-497, 2015

关键词： circular synthetic aperture radar layover back-projection algorithm clutter reduction automatic target detection

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Topography-Dependent Eikonal Traveltime Tomography for Upper Crustal Structure Beneath an Irregular Surface

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PURE AND APPLIED GEOPHYSICS 2015年第6期172卷 1511-1529页

作者： Ma, Ting Zhang, Zhongjie Chinese Acad Sci Inst Geol & Geophys State Key Lab Lithospher Evolut Beijing 100029 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

Seismic modeling of the crust with nonflat topography can be made by first-arrival traveltime tomography, which faces the challenge of an irregular free surface. A feasible way to deal with this problem consists of expanding the physical space by overlapping a low velocity layer above the irregular surface in order to have a flat topography, besides using the classical eikonal equation solver for traveltime computation. However, the undesirable consequences of this method include seismic ray deviations due to the transition from an irregular surface that is the free boundary to an inner discontinuity lying in the expanded computational space. An alternative solution, called irregular surface flattening, which involves the transformation between curvilinear and Cartesian coordinate systems, has been recently proposed through the formulation of the topography-dependent eikonal equation (TDEE) and a new solver for forward modeling of traveltimes. Based on the solution of this equation, we present topography-dependent eikonal traveltime tomography (hereafter TDETT) for seismic modeling of the upper crust. First-arrival traveltimes are calculated using the TDEE solver and the raypaths with the minimum traveltime that can be found by following the steepest traveltime gradient from the receiver to the source. By solving an algebraic equation system that connects the slowness perturbations with the already determined traveltimes, these variables can be obtained making use of the back-projection algorithm. This working scheme is evaluated through three numerical examples with different topographic complexities that are conducted from synthetic data and a fourth example with somewhat more complicated topography and real data acquired in northeastern Tibet. The comparison of the results obtained by both methods, i.e., physical space expansion above the irregular surface and irregular surface flattening, fully validates the tomography scheme that is proposed to construct seismi

关键词： Upper crust first-arrival traveltime tomography velocity structure topography-dependent Eikonal equation solver back-projection algorithm

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Comparison of SIMO-Based Wavenumber Domain and back-projection Imaging algorithms

Comparison of SIMO-Based Wavenumber Domain and Back-Projecti...

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Asia-Pacific Microwave Conference

作者： Shuang Liu Shiyong Li Guoqiang Zhao Houjun Sun Beijing Key Laboratory of Millimeter Wave and Terahertz Technology Beijing Institute of Technology

ISBN: (纸本)9781479987689

The single-input multiple-output (SIMO) array based imaging system has been applied for remote sensing and concealed weapon detection. In this paper, comparisons of the back-projection (BP) algorithm and wavenumber domain (ωk) algorithm applied to SIMO imaging are provided both in the near-field case and far-field case. Simulations demonstrate that the BP algorithm performs better in the near-field case. For the ωk algorithm, there would appear deviation and slight defocusing of the target due to the Taylor approximation in the near-field case. In the far-field case, the imaging result of BP algorithm is almost identical with that of ωk algorithm but the former would need more operation time.

关键词： Single input multiple output (SIMO) Wavenumber domain algorithm back-projection algorithm Two dimensional imaging

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Spaceborne-airborne SAR interferometry based on BP algorithm

Spaceborne-airborne SAR interferometry based on BP algorithm

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IET International Radar Conference 2015

作者： Xinxin Tang Xiaoling Zhang Shunjun Wei Jianing Liu University of Electronic Science and Technology of China

ISBN: (纸本)9781510822023

In this paper, an interferometric synthetic aperture radar (InSAR) technique based on spaceborne-airborne bistatic SAR interferometry (SA-BiInSAR) is presented, in which the transmitter and receivers are mounted on the spacecraft and aircraft respectively. Due to the separated transmitter and receivers, and also the common non-ideal trajectory of the airborne received platform, the conventional frequency-domain SAR imaging approaches, such as range-doppler algorithm and chirp scaling algorithm, are very difficult for SA-BiInSAR imaging processing directly. To obtain high-quality of SA-BiInSAR image formation and interferogram, in this paper a back-projection algorithm, based on time-domain coherent integration of target signals, is developed for SA-BiInSAR imaging and phase extraction in the case of non-ideal trajectory. In this scheme, the echoes of SA-BiInSAR master and slave channels are projected into the same imaging space, and the interferometric phase of SA-BiInSAR is derived utilizing the principle of BP algorithm. Simulation results demonstrate the performances of SA-BiInSAR, and verify the effectiveness of the presented BP algorithm for SA-BiInSAR image formation and phase extraction in the case of non-ideal trajectory.

关键词： SA-BiInSAR SAR Interferometry back-projection algorithm Interferometric phase Synthetic aperture radar projection algorithms Receivers algorithms interferometry interference pattern Transmitters Image formation trajectory Spacecraft

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Wide-field circular SAR imaging: 2D imaging results for simulation data

Wide-field circular SAR imaging: 2D imaging results for simu...

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6th International Conference on Recent Advances in Space Technologies (RAST)

作者： Demirci, Sevket Yigit, Enes Ozdemir, Caner Mersin Univ Dept Elect & Elect Engn Mersin Turkey

ISBN: (纸本)9781467363969;9781467363952

Circular synthetic aperture radar (CSAR) systems collect data over circular trajectories. Due to the curved, wide-angle geometry, focusing of CSAR data is known to be a difficult process. Additionally, when the spatial extent of the scene to be imaged is a significant fraction of the SAR path radius (i.e. in wide-field scenarios), layover phenomenon occurs which may further limit successful imaging of targets. In this paper, to characterize these layover effects, various simulation results for wide-field single-pass CSAR geometry are presented under point scattering assumption.

关键词： Circular synthetic aperutre radar (CSAR) synthetic aperture radar (SAR) near-field scattering back-projection algorithm

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Wide-field circular SAR imaging: 2D imaging results for simulation data

Wide-field circular SAR imaging: 2D imaging results for simu...

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International Conference on Recent Advances in Space Technologies

作者： Sevket Demirci Enes Yigit Caner Ozdemir The Department of Electrical and Electronics Engineering Mersin University

ISBN: (纸本)9781467363952

关键词： Circular synthetic aperutre radar (CSAR) Synthetic aperture radar (SAR) Near-field scattering back-projection algorithm

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