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Proceedings of the 5th International Conference on Information Technologies and Electrical Engineering

作者： Yi Jiang Shizhao Huang School of Electronic Engineering AnHui XinHua University China

ISBN: (纸本)9781450396806

Conventional spaceborne SAR is limited by range and Doppler blur, so it cannot achieve simultaneous high-resolution wide mapping band. To solve this problem, this paper adopts the multi-channel ScanSAR technology scheme of azimuth-oriented multi-phase center bias combined with range beam scanning. The application of multi-channel system in ScanSAR operation mode can effectively make up for the defects of low azimuth-oriented resolution of conventional ScanSAR, so as to obtain high resolution wide mapping band. This paper describes the principle of multi-channel ScanSAR to realize high-resolution wide-band mapping, and proposes a multi-channel frequency domain reconstruction algorithm combined with full-aperture RD algorithm to realize multi-channel ScanSAR imaging. The effectiveness of the algorithm is verified by 7×7 lattice imaging simulation, which lays a foundation for the engineering implementation of high-resolution wide-band mapping SAR.

关键词： imaging algorithm High resolution Beam scanning Multichannel ScanSAR

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A Novel imaging algorithm for High-Resolution Wide-Swath Space-Borne SAR Based on a Spatial-Variant Equivalent Squint Range Model

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REMOTE SENSING 2022年第2期14卷 368-368页

作者： Guo, Yanan Wang, Pengbo Chen, Jie Men, Zhirong Cui, Lei Zhuang, Lei Beihang Univ Sch Elect & Informat Engn Beijing 100191 Peoples R China Shanghai Inst Satellite Engn Shanghai 201100 Peoples R China

High-Resolution Wide-Swath (HRWS) is an important development direction of space-borne Synthetic Aperture Radar (SAR). The two-dimensional spatial variation of the Doppler parameters is the most significant characteristic of the sliding spotlight space-borne SAR system under the requirements of HRWS. Therefore, the compensation of the two-dimensional spatial variation is the most challenging problem faced in the imaging of HRWS situations. The compensatory approach is then proposed to address this problem in this paper. The spatial distribution of the Doppler parameters for the HRWS space-borne SAR data in the sliding spotlight working mode is firstly analyzed, based on which a Spatial-Variant Equivalent Slant Range Model (SV-ESRM) is put forward to accurately formulate the range history for the distributed target. By introducing an azimuth-varying term, the SV-ESRM can precisely describe the range history for not only central targets but also marginal targets, which is more adaptive to the HRWS space-borne SAR requirements. Based on the SV-ESRM, a Modified Hybrid Correlation algorithm (MHCA) for HRWS space-borne SAR imaging is derived to focus the full-scene data on one single imaging processing. A Doppler phase perturbation incorporated with the sub-aperture method is firstly performed to eliminate the azimuth variation of the Doppler parameters and remove the Doppler spectrum aliasing. Then, an advanced hybrid correlation is employed to achieve the precise differential Range Cell Migration (RCM) correction and Doppler phase compensation. A range phase perturbation method is also utilized to eliminate the range profile defocusing caused by range-azimuth coupling for marginal targets. Finally, a de-rotation processing is performed to remove the azimuth aliasing and the residual azimuth-variance and obtain the precisely focused SAR image. Simulation shows that the SAR echoes for a 20 km x 20 km scene with a 0.25 m resolution in both the range and azimuth directions

关键词： synthetic aperture radar (SAR) high-resolution wide-swath (HRWS) Spatial-Variant Equivalent Slant Range Model (SV-ESRM) imaging algorithm Doppler phase perturbation

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KT and azimuth sub-region deramp-based high-squint SAR imaging algorithm mounted on manoeuvring platforms

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IET RADAR SONAR AND NAVIGATION 2020年第3期14卷 388-398页

作者： Li, Gen Ma, Yanheng Shi, Lin Hou, Jianqiang Army Engn Univ Dept UAV Engn Shijiazhuang Campus Shijiazhuang 050003 Hebei Peoples R China Army Engn Univ Dept Elect & Opt Engn Shijiazhuang Campus Shijiazhuang 050003 Hebei Peoples R China

Owing to the existence of high-order motion parameters and vertical velocity, severe range-azimuth coupling and two-dimensional spatial variability of the imaging parameters degrade the image quality of high-squint synthetic aperture radar (SAR) mounted on manoeuvring platforms. To accommodate these issues, a novel sub-aperture SAR imaging algorithm based on keystone transform (KT) and azimuth sub-region deramp is proposed. In the range dimension processing, a correction function is constructed based on the scene centre to realise non-spatial-variant range cell migration (RCM) correction and range-azimuth decoupling, and then the residual spatial-variant RCM is removed by the KT. In the azimuth dimension processing, considering the impact of the range distortion on the azimuth modulated phase, accurate analytical formula of the signal in the azimuth time domain is deduced. On this basis, a fast azimuth compression method based on the azimuth sub-region deramp is proposed, and the theoretical effective imaging area is analysed. The theoretical analysis and the simulations show that the proposed imaging algorithm has high computational efficiency and can effectively expand the imaging area of high-squint SAR mounted on manoeuvring platforms.

关键词： radar imaging synthetic aperture radar frequency-domain analysis transforms data compression range distortion azimuth modulated phase azimuth time domain fast azimuth compression method theoretical effective imaging area imaging algorithm high computational efficiency manoeuvring platforms azimuth sub-region deramp-based high-squint SAR high-order motion parameters severe range-azimuth coupling two-dimensional spatial variability imaging parameters image quality high-squint synthetic aperture radar sub-aperture SAR range dimension processing nonspatial-variant range cell migration correction range-azimuth decoupling spatial-variant RCM azimuth dimension processing

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An imaging algorithm for High-speed Side-scan Sonar Based on Multi-beam Forming Technology

An Imaging Algorithm for High-speed Side-scan Sonar Based on...

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Global OCEANS Singapore - U.S. Gulf Coast Conference

作者： Meng Xiang-Jian Xu Wen Shen Bin-jian Guo Xinxin Liu Xin-yu Liu Yushi Chinese Acad Sci Inst Deep Sea Sci & Engn Sanya Peoples R China Univ Chinese Acad Sci Beijing Peoples R China Zhejiang Univ Ocean Coll Zhoushan Peoples R China

ISBN: (数字)9781728154466

ISBN: (纸本)9781728154466

With the increasing attention on oceanography, more effective exploration technology has been of great interests in the community of ocean engineering. Side-scan sonar is a popular imaging equipment for seabed topography;however, it is commonly used under 4 knots, which does not meet the actual demand of the modern oceanographic research. This paper proposes a high-speed side-scan sonar imaging scheme based on multi-beam forming technology. In this scheme, the digital signal processing system can adjust the maximum response direction of the receiving array by introducing appropriate phase shift or time delay to the output, so as to increase the scanning range and then improve operation efficiency. In order to verify the feasibility of this imaging algorithm, an ocean environment model is constructed, which simulates the acoustic propagation theory, the principle of seabed acoustic backscattering and the acoustic signal modulation method. After analyzing the acoustic characteristics of uniform linear array, an underwater acoustic transducer with multiple receiving subarrays is designed. In the process of simulated navigation, the receiving subarrays will generate the electrical signal containing seabed acoustic information. Based on the simulation signal, the parameters of the digital filter in the actual system can be determined in advance, which provides convenience for later processing. The time delay matrix of each receiving channel based on dynamic focusing beamforming method can be verified by imaging the seabed model. The processed acoustic data are combined with GPS information and heading angle to generate seabed scanning image in the host computer system. This paper mainly presents the imaging algorithm of multi-beam side-scan sonar digital signal processing system.

关键词： side-scan sonar imaging algorithm multi-beam forming technology seabed topography

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Fractional Fourier Transform based imaging algorithm for Near-range Radar and Discretisation Formats

Fractional Fourier Transform based Imaging Algorithm for Nea...

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SPIE Future Sensing Technologies Conference

作者： Zou, Lilong Tosti, Fabio Alani, Amir M. Univ West London London Sch Comp & Engn St Marys Rd London W5 5RF England

ISBN: (纸本)9781510638624;9781510638617

In this work, the novel imaging algorithm of synthetic aperture radar (SAR) system to be used in near-range based on fractional Fourier transform is presented. The algorithm projects the target reflectivity function onto pseudopolar coordinates and focuses along the short time through the fractional Fourier transform. The discrete format procedure for imaging near-range target is also introduced in this paper. The numerical simulation results show that the algorithm is more suitable for the high-precision synthetic aperture radar imaging in the near field.

关键词： imaging algorithm near-range radar fractional Fourier transform synthetic aperture radar matrix description

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A novel computational imaging algorithm based on split Bregman iterative for electrical capacitance tomography

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MEASUREMENT SCIENCE AND TECHNOLOGY 2021年第12期32卷 125401-125401页

作者： Zhao, Qing Liu, Shi Chai, Xinxin Guo, Hongbo North China Elect Power Univ Sch Control & Comp Engn Beijing 102206 Peoples R China China Railway Xian Grp Co Ltd Vehicle Depot Xian 710000 Shanxi Peoples R China Acad Mil Med Sci Natl Innovat Inst Def Technol Beijing 100000 Peoples R China

As an advanced detection technology in the industrial field, electrical capacitance tomography (ECT) can better reconstruct the material distribution state in the measured area by selecting the appropriate algorithm. In order to improve the reconstruction quality, this paper devises a novel objective function to model the ECT image reconstruction problem, in which L (1)-norm is deployed as data fidelity with the focus on weakening the influence of capacitance outliers on the reconstruction quality, L (P) regularization reinforces the sparseness of the phantom objects, and L (1) regularization applies to model deviation variables to increase the robustness of the system. Based on the fast-iterative shrinkage thresholding technique and the soft thresholding method as sub-solvers, the split Bregman iterative method is designed as an effective solver for the proposed objective function. Numerical simulation and experimental validate that the proposed algorithm has excellent imaging ability compared with other imaging algorithms, which provides a good choice for the practical application of ECT in the future.

关键词： electrical capacitance tomography imaging algorithm Tikhonov regularization split Bregman iterative method

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An Efficient and Accurate GB-SAR imaging algorithm Based on the Fractional Fourier Transform

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2019年第11期57卷 9081-9089页

作者： Zou, Lilong Sato, Motoyuki Univ West London Sch Comp & Engn London W5 5RF England Tohoku Univ Ctr Northeast Asian Studies Sendai Miyagi 9808576 Japan

In this paper, an efficient and accurate imaging algorithm is presented for Ground-Based Synthetic Aperture Radar (GB-SAR) or other radar systems that could be formed by a physical or synthetic linear aperture. The imaging algorithm is based on the fractional Fourier transform (FrFT) for the azimuth compression. A mathematical framework is derived according to the projection of a sample reflectivity image onto the pseudopolar coordinate, and its implementation was presented. With the data acquisition geometry and the pseudopolar imaging coordinate, the phase of a point target can be expressed as a quadratic phase exponential. It makes that only 1-D FrFT is needed for the azimuth compression of the time-domain backscatter data for the GB-SAR imaging problem. By further research, the optimal transformation order that represents the spatial frequency changes by the FrFT was given subsequently. Taking advantage of this optimal representation, the proposed approach avoids the large calculation that occurs in the time-domain back projection (TDBP). Comparing to the far-field pseudopolar format algorithm (FPFA), the accuracy of the proposed algorithm is much improved. Meanwhile, the proposed approach holds almost the same computational cost and complexity as the FPFA. The proposed approach keeps the advantages of the imaging quality of the TDBP and the computational cost of the FPFA that are two important aspects of the GB-SAR applications. Both the numerical simulation and the field GB-SAR experiment show that the algorithm is more suitable for the high-precision GB-SAR imaging, especially for the near field.

关键词： Radar imaging Time-domain analysis Synthetic aperture radar Focusing Apertures Fourier transforms Ground-Based Synthetic Aperture Radar (GB-SAR) imaging algorithm linear aperture radar near-field imaging fractional Fourier transform (FrFT)

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High-resolution imaging algorithm based on temporal focal characteristic of time-reversed signal

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SYSTEMS SCIENCE & CONTROL ENGINEERING 2019年第1期7卷 198-209页

作者： Zhang, Guangmin Zhu, Junxiao Li, Jiaquan Wang, Ning Dongguan Univ Technol Sch Elect Engn & Intelligentizat Dongguan Peoples R China Univ Houston Dept Mech Engn Houston TX USA Texas Southern Univ Dept Comp Sci Houston TX 77004 USA

Although the high-resolution materials can improve the resolution of the conventional time-reversal imaging (TRI) algorithms, they also limit the applications of TRI. In this paper, a new TRI algorithm with high-resolution is presented. Since the proposed algorithm utilizes multiple time reversal operation steps to improve resolution, it can realize high-resolution without invoking any high-resolution materials. The results show the resolution of the proposed algorithm is superior to that of the conventional TRI.

关键词： High-resolution imaging algorithm time-reversal

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New imaging algorithm for material damage localisation based on impedance measurements under noise influence

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MEASUREMENT 2020年 163卷 107953-107953页

作者： de Castro, Bruno Albuquerque Baptista, Fabricio Guimaraes Ciampa, Francesco Sao Paulo State Univ UNESP Sch Engn Dept Elect Engn BR-17033360 Bauru SP Brazil Univ Surrey Fac Engn & Phys Sci Dept Mech Engn Sci Aerosp Div Guildford GU2 7XH Surrey England

The electro-mechanical impedance (EMI) measurements have been extensively studied in recent years to provide a reliable diagnosis of aerospace infrastructures. Existing imaging algorithms for EMI-based damage localisation have been proposed for controlled inspection environments or under the sole influence of temperature variations. However, the presence of signal noise may alter impedance signals and limit the use of the EMI method in real operating scenarios. Based on this issue, this short communication proposes a novel EMI probabilistic imaging algorithm for damage localisation under noisy inspections. Furthermore, as another advantage compared to traditional techniques, which do not perform a noise compensation, the proposed application does not require high computational cost since it does not require licensed software or the calculation of acoustic parameters. Experimental results on an aluminium plate-like structure revealed that the new algorithm proved to be adequate to image the location of damage under noise influence as opposed to traditional approaches. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Impedance measurements SHM imaging algorithm Signal processing Probabilistic image CCSD Damage localisation

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imaging algorithm for multi-channel scan synthetic aperture radar with channel error estimation and compensation

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JOURNAL OF ENGINEERING-JOE 2019年第20期2019卷 6688-6691页

作者： Xiao, Feng Ding, Zegang Ke, Meng Beijing Inst Technol Sch Informat & Elect Radar Res Lab Beijing Key Lab Embedded Real Time Informat Proc Beijing 100081 Peoples R China

The wide swath synthetic aperture radar (SAR) imaging with a fine resolution is fundamentally a contradiction in conventional SAR imaging. To meet the demand of high-resolution width swath (HRWS) imaging, multi-channel scan mode has received a great deal of attention as a promising concept to realise HRWS observation. In this article, based on extended Chirp Scaling algorithm, an imaging algorithm for multi-channel scan SAR is proposed. Furthermore, channel error estimation and compensation are the key point in multi-channel scan imaging and are integrated into the proposed imaging algorithm. The computer simulation is shown to verify the presented imaging algorithm.

关键词： synthetic aperture radar radar imaging geophysical image processing image resolution HRWS observation imaging algorithm wide swath synthetic aperture radar multichannel scan synthetic aperture radar multichannel scan imaging channel error estimation multichannel scan SAR extended Chirp Scaling algorithm multichannel scan mode high-resolution width swath imaging conventional SAR imaging fine resolution

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