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Synthetic Aperture Radar, 2009. APSAR 2009. 2nd Asian-Pacific Conference on

Date 26-30 Oct. 2009

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Displaying Results 1 - 25 of 267
  • Imaging and locating multiple ground moving targets based on keystone transform and FrFT for single channel SAR system

    Page(s): 771 - 774
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (197 KB) |  | HTML iconHTML  

    Synthetic aperture radar (SAR) imaging techniques have been successfully developed for static ground targets, but if the moving target returns are processed in the conventional imaging way, the resulting SAR image of moving targets will appear blurred and be misplaced in azimuth direction. In this paper, we proposed a method which is based on keystone transform and fractional Fourier transform (FrFT) to solve these problems. Firstly, first order keystone transform is performed on range compression results to correct range walk, then estimates of Doppler Centroid and Doppler modulation rate are obtained by using fractional Fourier transform, finally focused image of multiple moving targets is achieved by making use of the Doppler estimates. It can ascertain initial positions of multiple moving targets; moreover, it can estimate azimuth velocity, radial velocity and radial acceleration for every moving target. The simulation results show that this method can image and locate multiple ground moving targets effectively. View full abstract»

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  • 3-D back-projection imaging in circular SAR with impulse signal

    Page(s): 775 - 778
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (169 KB) |  | HTML iconHTML  

    Circular Synthetic Aperture Radar (CSAR) travels along a circular track and can obtain a 3-D image for the observed space. Conventional 2-D Back-projection imaging algorithm is transformed to 3-D Back-Projection (BP) algorithm for Circular SAR here, which adopts impulse signals. This algorithm is compared with the confocal imaging algorithm, and they are essentially the same which has been proved in this paper. So the analysis with ¿generalized ambiguity function¿, which is used by the confocal algorithm, is introduced here to analyze the vertical resolution of 3-D BP algorithm. Some simulations demonstrate the validity of the algorithm and the resolution analysis result. Finally, an outside experiment shows the practical 3-D imaging result. View full abstract»

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  • An eigenspace-like algorithm for multibaseline InSAR phase unwrapping

    Page(s): 779 - 783
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (735 KB) |  | HTML iconHTML  

    In this work we present an eigenspace-like technique for the estimation of the unwrapped phase which is based on the model of the multi-baseline joint data group. The method is shown to work well even in the presence of the image coregistration misalignment and the steering vector mismatch, and has the ability to overcome the conflict associated with the computational complexity and the lack of the independent and identically distributed (i.i.d.) samples. The performance analysis of the technique is carried out based on Monte Carlo simulations and Cramer-Rao lower bounds (CRLBs) calculation. Numerical results on simulated data demonstrate the efficiency and precision of the proposed method. View full abstract»

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  • Research on parallel processing of SAR imaging algorithm

    Page(s): 784 - 787
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (89 KB) |  | HTML iconHTML  

    A parallel SAR imaging algorithm based on RDA is presented in this paper on the basis of the existing sequential algorithms after deeply studying parallel processing of SAR imaging. The algorithm which is on task level adapts well to the parallel processing system with high communication performance. The results of experiments on IBM blade server verify that the algorithm has highly real time property and parallel efficiency. View full abstract»

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  • A track-to-track association algorithm with chaotic neural network

    Page(s): 788 - 791
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (86 KB) |  | HTML iconHTML  

    A great deal of attentions is currently focused on multisensor data fusion. A very important aspect of it is track-to-track association and track fusion in distributed multisensor-multitarget environments. The approach based on Hopfield neural network has been developed. But the performance of this approach is limited because Hopfield neural network is often trapped in the local minima. This paper try to solve this problem with an approach based on chaotic neural network (CNN). Furthermore, in order to improve the performance of neural network, the association statistic between tracks from different sensors is modified. Computer simulation results indicate that this approach is more efficient than the algorithm based on continuous Hopfield neural network (CHNN). View full abstract»

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  • Feature extraction method for micro-Doppler using LFM

    Page(s): 792 - 795
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (93 KB) |  | HTML iconHTML  

    This paper mainly deals with the problem of extracting the micro-Doppler feature. The micro-Doppler can be regarded as the unique signature of the micro-motion target. Based on introducing the concept of the micro-Doppler, a method is proposed to extract the micro-Doppler feature, which can estimate two micro-motion parameters, i.e., initial angle and frequency simultaneously. Then the mathematical formula of this method is derived. Finally, the computer simulation confirms theoretical analysis, providing theoretical foundation for micro-Doppler feature extraction. View full abstract»

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  • SAR image retrieval based on Gaussian Mixture Model classification

    Page(s): 796 - 799
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (116 KB) |  | HTML iconHTML  

    SAR image retrieval, lacking of well performance recently due to the particularity of SAR image, has drawn more and more attention with the increasing volume of SAR data and the dramatically enlarging application range of SAR image. This paper considers both the characteristic of content-based image retrieval (CBIR) and SAR image, proposing a novel SAR image retrieval method. The proposed method can be divided into two parts: image classification and matching. Firstly we use Gaussian Mixture Model (GMM) to gain a precise result of classification, and then we get the retrieval results through the integrated region matching (IRM) algorithm. Experimental results show that the proposed method can retrieve SAR images which contain all kinds of surface features effectively. View full abstract»

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  • Derivation of bald earth digital elevation models with X band airborne InSAR

    Page(s): 800 - 804
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB) |  | HTML iconHTML  

    Interferometric Synthetic Aperture Radar (InSAR) is a powerful instrument for large scale acquisition of height data for bare earth as well as for vegetated areas and artificial above-ground objects. For many applications, the generation of a bald earth digital elevation model (DEM) is also required. This paper introduces the method of generating a bald earth DEM, referred to as the hierarchical surface fitting technique [7], which operates on the digital surface models (DSM) created using the X band InSAR data provided by the Institute of Electronic, Chinese Academe Sciences. After a short description of the algorithms, the paper presents the results of this technique applied to several DSM data sets, which are accomplished by VC++ program and show that this technique can remove artificial above-ground objects while retaining most of the detail of the original data. View full abstract»

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  • Polarimetric SAR image classification using Multiple-Component Scattering Model and Support Vector Machine

    Page(s): 805 - 808
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB) |  | HTML iconHTML  

    The classification of polarimetric SAR image based on Multiple-Component Scattering Model (MCSM) and Support Vector Machine (SVM) is presented in this paper. MCSM is a potential decomposition method for a general condition. SVM is a popular tool for machine learning tasks involving classification, recognition or detection. The scattering powers of single-bounce, double-bounce, volume, helix, and wire scattering components are extracted from full polarimetric SAR images. Combined with the scattering power and the texture feature, SVM is used for the polarimetric classification. We generate a validity test for the method using EMISAR L-band full polarized data of Foulum Area (DK), Denmark. The preliminary result indicates that this method can classify most of the areas correctly. View full abstract»

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  • Unsupervised SAR image segmentation based on quantum-inspired evolutionary gaussian mixture model

    Page(s): 809 - 812
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (221 KB) |  | HTML iconHTML  

    In this paper, an unsupervised SAR image segmentation algorithm (QEAGMM) based on quantum-inspired evolutionary Gaussian Mixture Models (GMM) is proposed. The method first divides the original image into small blocks. Then, the heterogeneous and homogeneous blocks are obtained using FCM clustering. Finally, the parameters of gaussian mixture model are trained by expectation-maximization (EM) algorithm using a part of homogeneous samples. However, the EM algorithm is apt to fall into a local optimum and the result is sensitive to initialization. So we embed the EM algorithm in quantum evolutionary algorithm (QEA) and propose a quantum-inspired-based EM algorithm (QEA-EM) to train the gaussian mixture model. This method not only improves the accuracy of parameters estimation but also performs better than immune clonal selection EM algorithm (ICSEM) on computational complexity. The experimental results show that compared to gaussian mixture model clustering algorithm (GMMC), the proposed method is successfully applied to texture mosaic images and SAR images, and shows overall improvement in performance. View full abstract»

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  • Study on outline extraction for ground buildings in high resolution SAR images

    Page(s): 813 - 816
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (300 KB) |  | HTML iconHTML  

    This paper analyses the visual characteristics of ground buildings in high resolution SAR images: the L-shaped echoes resulted from layer over and corner reflection effects give expression to the information of location and height of buildings. Therefore, to vectorize the L-shaped outline of the buildings has a great value in the field of city mapping. Focusing on L-shaped echoes, this paper investigates an outline vectorization algorithm for buildings. Firstly, the method counters the image after segmentation, then gets the main direction of buildings based on Hough Transform. After using polygon approaches on the outline, finally, the method adopts piecewise linear fitting by least-square algorithm and constructs 3-D model of buildings. Experiments on SAR images show that this approach is much fast in extraction of ground buildings with convenience and practicality. View full abstract»

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  • SAR image segmentation using quantum clonal selection clustering

    Page(s): 817 - 820
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB) |  | HTML iconHTML  

    A novel clustering algorithm is proposed, which is derived from physical intuition of quantum mechanics and biological principle based on immune clonal selection. As extension ideas of scale-space clustering and support vector clustering, quantum clustering method deduces the clustering allocation by gradient descent, which is prone to getting stuck in local extremes. By designing a novel and high-efficiency affinity function, we adopt an immune clonal selection algorithm with elite preservation strategy to search the global optimum. The experimental results on texture images and SAR images segmentation we demonstrate show that quantum clonal selection clustering method performs well both in precision and efficiency. View full abstract»

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  • Change detection based on image segment and fusion in multitemporal SAR images

    Page(s): 821 - 824
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (302 KB) |  | HTML iconHTML  

    In this paper, a new change detection method based on image segmentation and fusion in multi-temporal SAR image is presented. The proposed fusion method exploits the conditional probability of difference image to two original images to fuse the segment results of two original SAR images. The new method can be divided into four steps: (1) the original SAR images are segmented into two classes using the proposed segmentation method based on canny edge match. (2) The two segmentation result images are fused with conditional probability rule and a fusion difference image considering spatial context is obtained. (3) The fusion image is thresholded with OTSU threshold, and the initial change detection result is obtained. (4) With subtraction operation and absolute operation between two segment results of original SAR images, a Boolean image with 0 and 1 value is obtained. Then the change detection result is composed of the regions in the Boolean image corresponding to the change regions in the initial change detection result. Experimental results obtained on simulate and real SAR images confirm the effectiveness of the proposed approach. View full abstract»

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  • A novel registration method for interferometric SAR images

    Page(s): 825 - 827
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (174 KB) |  | HTML iconHTML  

    In this paper, an novel method for interferometric synthetic aperture radar (InSAR) image registration is proposed. The approach is more accurate than conventional methods since it uses a continuous interpolation technique. The approach gets rid of the limitation of restricted registration accuracy caused by discrete interpolation. The performances of the proposed method are shown by using simulated and real data and compared with those of representative existing registration method. View full abstract»

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  • A new orbit fitting algorithm of space-borne SAR based on householder transformation

    Page(s): 832 - 835
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (350 KB) |  | HTML iconHTML  

    With the development of space-borne SAR and wide application of SAR image, the accurate positioning in geometric rectification of SAR image becomes more and more important. It corrects the image by using orbit parameters and RD location model. The orbit parameter accuracy affects the accuracy of geo-coding directly. In this paper, a new orbit fitting algorithm based on householder transformation is presented. A comparison which uses ENVISAT images as the experimental data is made between householder transformation algorithm and the traditional least squares polynomial fitting, the result shows that the new algorithm in this paper not only avoids the ill condition of traditional least squares polynomial fitting, but also have a higher positioning accuracy. View full abstract»

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  • Downward-looking 3D-SAR with dual-transmit and multiple-receive linear array antennas based on time and waveform diversity

    Page(s): 17 - 20
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (219 KB) |  | HTML iconHTML  

    The dual-transmit and multiple-receive (DTMR) configuration of linear array antennas (LAA) is firstly introduced in downward-looking 3D-SAR imaging in this paper. The geometrical model and the signal model based on the principle of time diversity and waveform diversity are analyzed. The three-dimensional imaging processing algorithm for downward-looking 3D-SAR with DTMR-LAA is given via a stepwise mathematical derivation and the analytic expression of 3D PSF after 3D imaging processing is presented. The simulation results confirm the feasibility of the downward-looking 3D-SAR with DTMR-LAA imaging concept. View full abstract»

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  • Imaging model of forward-looking ground penetrating radar with split-aperture transmitting configuration

    Page(s): 21 - 24
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (119 KB) |  | HTML iconHTML  

    In this paper, a novel antenna configuration for the forward-looking ground penetrating radar is studied. In the novel configuration, the two transmitting antennas are located at two ends of the receiving array, which is referred to as the split-aperture transmitting (SAT) configuration. Firstly, a modified back-projection (MBP) image formation is proposed according to the imaging geometry of the SAT configuration. And then the analytical azimuth resolution expression of the SAT configuration is derived. Based on the analytical form of the azimuth resolution, the relationship of target scattering information between received raw echo and focused imagery is obtained. The theoretic calculation and analysis in this paper are validated by the field data of the forward-looking ground penetrating radar with the SAT configuration developed by the National University of Defense Technology (NUDT). View full abstract»

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  • Investigation on converse beam cross sliding spotlight SAR

    Page(s): 25 - 28
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (165 KB) |  | HTML iconHTML  

    This is the first investigation on converse beam cross sliding spotlight SAR (CBC sliding spotlight SAR) which was firstly proposed in this essay. In conventional sliding spotlight SAR, the azimuth scene extension is larger than that of a pure spotlight mode and the azimuth resolution of scatterers is higher than in classical stripmap mode. The geometry and properties of classical standard and inverse sliding spotlight SAR were reviewed and a novel operation mode called converse beam cross sliding spotlight SAR was proposed in this essay. It's imaging geometry and properties were detailed investigated and a unified sliding factor was deduced, both classical sliding spotlight SAR and CBC sliding spotlight SAR can be realized by choosing a proper sliding factor. Simulations were executed and the point spread functions were gained. All results proved that CBC sliding spotlight SAR can gain images with azimuth resolution higher than stripmap SAR, azimuth scene extension larger than pure spotlight SAR and it plays an important complementary function in completing the operation mode of SAR. View full abstract»

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  • Experimental analysis of vehicle imaging verification of airborne SAR system

    Page(s): 29 - 33
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (200 KB) |  | HTML iconHTML  

    This paper presents the ground vehicle imaging test of the airborne SAR system, shows the imaging results through point targets simulation in detail, analyses the effects of slow SAR platform based on ground vehicle imaging results. Finally, the analysis and scheme are validated by the results on vehicle imaging. View full abstract»

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  • C-Band multi-polarimetric SAR and the flight experiment of land and sea

    Page(s): 34 - 38
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (459 KB) |  | HTML iconHTML  

    The C-Band multi-polarization SAR system has a wide range of applications in the earth observation field, and it can be applied to ocean observing, crop monitoring, mapping and other fields. The application flight experiment is introduced, and some SAR image, inversion results of land, sea are presented. View full abstract»

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  • Angle and doppier ambiguity mitigation for spaceborne sparse array GMTI radar

    Page(s): 39 - 42
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (305 KB) |  | HTML iconHTML  

    Ground moving target indication (GMTI) using spaceborne sparse array radar is attractive. To mitigate angle and Doppler ambiguities of the moving target detection for sparse array, the paper presented the model of a multi-carrier-frequency radar system and analyzed the basic principle of space time adaptive processing (STAP). Finally, the paper presented preliminary simulations to show that the angle and Doppler ambiguities can be effectively reduced by using multi-carrier-frequency technique. View full abstract»

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  • Analysis of bistatic ground clutter characteristics and effects on space-time adaptive processing

    Page(s): 43 - 47
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (140 KB) |  | HTML iconHTML  

    In-depth study of ground clutter characteristics of airborne bistatic radar is significant to clutter suppression and moving target detection (MTD) through space-time adaptive processing (STAP). Based on the geometry configuration that transmitter and receiver align at the same velocity, the paper presents the equation of ellipse on ground and analytic resolution of clutter scatterer location when the two-way distance between receiver and transmitter is constant, derives the clutter ridge expression and gives theoretic explanations to the nonlinear and nonstationary properties of bistatic clutter. Changes of clutter ridge are given under mathematical analysis; meanwhile, STAP performance is briefly analyzed with parameters of platforms at different bounds. Simulations verify the correctness of conclusions given in the paper. View full abstract»

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  • Study on synthetic aperture imaging lidar based on a laboratory-scale sliding guide system

    Page(s): 48 - 50
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (147 KB) |  | HTML iconHTML  

    Synthetic Aperture Imaging Lidar (SAIL) is an extension of conventional microwave Synthetic Aperture Radar (SAR) to much shorter wavelengths (by a factor of about 100,000). This kind of active imaging radar can offer finer resolution and better image feature which is closer to optical image. In this paper, we introduce our laboratory-scale SAIL system in detail, elaborate difficulties that we have solved and will solve, and report our infrared optical synthetic aperture image of a fixed, diffusely scattering target with an aperture moving along with a sliding guide. View full abstract»

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  • Investigation on spatial resolving capability of bistatic SAR

    Page(s): 51 - 54
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (231 KB) |  | HTML iconHTML  

    Bistatic synthetic aperture radar (Bistatic SAR) have became the focus of increasing research activity these years, but the resolution of bistatic SAR is quite complex than that of monostatic SAR. In this paper, a general approach to estimate bistatic SAR ground range resolution based on spatial gradient is developed. This approach has more adaptability and can be agilely applied to different bistatic SAR configuration. The characteristic of gradient is analyzed and ground range resolution based on the spatial gradient is deduced. Detailed simulations test the validity of this approach and range resolution distribution in ground plane of airborne bistatic SAR is analyzed. View full abstract»

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  • Azimuth resolution acquisition through trajectory optimization for a SAR seeker

    Page(s): 55 - 59
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (110 KB) |  | HTML iconHTML  

    For a SAR seeker, how to acquire the best azimuth resolution within a fixed time is still a problem. As well known, the trajectory and the look angle have an effect on the azimuth resolution of imaging. This paper proposes a trajectory design and optimization method based on genetic algorithms. It builds the constraints of the missile at the flight time, uses a sequence of piecewise constant command acceleration demands as the control variables, sets up the objective function about the dwell time and the desired azimuth resolution, optimizes the control variables using the genetic algorithm, and so gets the optimal trajectory. Simulation results demonstrate the validity of the method. View full abstract»

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