The phase noise suppression methods applied on the interferogram of Interferometric synthetic aperture radar (InSAR) are studied. Filtering phase noise in an interferogram is an important aspect in InSAR data processi...
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The phase noise suppression methods applied on the interferogram of Interferometric synthetic aperture radar (InSAR) are studied. Filtering phase noise in an interferogram is an important aspect in InSAR data processing. But any improper altering of the wrapped phase may influence the quality of derived DEM because the interferometric phase contains the topographic information. Therefore, one of the difficulties in phase noise filtering is how to remove the noise and preserve the spatial resolution effectively. In this paper, a new adaptive approach based on the nonlinear anisotropic diffusion equation is presented for removing the noise in the interferogram. The key idea is that for low gradients, isotropic smoothing is performed, and for high gradient, smoothing is only applied in the direction of the isophote and not across it. During the course of noise suppressing, image features and their directions are extracted. Less smoothing is in the locations with strong image feature, and more smoothing in the locations with weak image feature;minimal smoothing in the directions across the image features, and maximal smoothing in the directions along the image features. At the end of this paper, this approach is compared with some existing approachs for InSAR noise filtering and the experimental results by processing Canada Radarsatl data are used to confirm that the method is more effective in suppressing noise in the interferogram.
The paper presents a new class of memory gradient methods with inexact line searches for unconstrained minimization problems. The methods use more previous iterative information than other methods to generate a search...
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Two kinds of algebraic multigrid (AMG) algorithms with three-dimensional equal algebraic structures are constructed on the basis of a two-dimensional coarsing technique. The AMG method and the corresponding algebraic ...
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Two kinds of algebraic multigrid (AMG) algorithms with three-dimensional equal algebraic structures are constructed on the basis of a two-dimensional coarsing technique. The AMG method and the corresponding algebraic multigrid-preconditioned CG method are applied to elliptic boundary value problems with smooth coefficients and anisotropic problems. Numerical results show that the AMG algorithm is efficient and robust.
Laplace-Beltrami operator and its discretization play a central role in several applications in the fields of computer graphics and computer aided geometric *** this paper,a discrete scheme for Laplace-Beltrami operat...
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Laplace-Beltrami operator and its discretization play a central role in several applications in the fields of computer graphics and computer aided geometric *** this paper,a discrete scheme for Laplace-Beltrami operator over quadrilateral meshes is constructed based on a bilinear interpolation of the quadrilateral. Convergence results for the proposed discrete scheme are established under some conditions.
We use two fourth order geometric partial differential equations to efficiently solve several surface modelling problems, including the surface blending, the N-sided hole filling and the free-form surface fitting with...
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We use two fourth order geometric partial differential equations to efficiently solve several surface modelling problems, including the surface blending, the N-sided hole filling and the free-form surface fitting with the G/sup 1/ boundary continuity. The nonlinear equations used include the surface diffusion flow and the Willmore flow. These nonlinear equations are discretized using the mixed finite element method based on the combination of the loop's basis and the linear basis. The proposed approach is simple, efficient and gives very desirable results.
Line search method and trust region method are two important classes of techniques for solving optimization problems and have their advantages respectively. In this paper we use the Armijo line search rule in a more a...
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Line search method and trust region method are two important classes of techniques for solving optimization problems and have their advantages respectively. In this paper we use the Armijo line search rule in a more accurate way and propose a new line search method for unconstrained optimization problems. Global convergence and convergence rate of the new method are analyzed under mild conditions. Furthermore, the new Armijo-type line search strategy is shown to be equivalent to an approximation of a trust region method then has both advantages of line search strategy and trust region strategy.
The mechanical properties of a model of Y-doped intergranular glassy film in silicon nitride ceramics are studied by large-scale ab initio modeling. By linking directly to its electronic structure, it is shown that th...
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The mechanical properties of a model of Y-doped intergranular glassy film in silicon nitride ceramics are studied by large-scale ab initio modeling. By linking directly to its electronic structure, it is shown that this microstructure has a complex nonlinear deformation under stress and Y doping significantly enhances the mechanical properties. The calculation of the electrostatic potential across the film supports the space charge model in ceramic microstructures.
This paper describes an automatic system for 3D face modeling using frontal and profile images taken by an ordinary digital camera. The system consists of four subsystems including frontal feature detection, profile f...
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In this paper the methods of wave theory based prestack depth migration and their implementation are studied. Using the splitting of wave operator, the wavefield extrapolation equations are deduced and the numerical s...
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In this paper the methods of wave theory based prestack depth migration and their implementation are studied. Using the splitting of wave operator, the wavefield extrapolation equations are deduced and the numerical schemes are presented. The numerical tests for SEG/EAEG model with MPI are performed on the PC-cluster. The numerical results show that the methods of single-shot (common-shot) migration and synthesized-shot migration are of practical values and can be applied to field data processing of 3D prestack depth migration.
In this paper we are concerned with a domain decomposition method with nonmatching grids for Raviart-Thomas finite elements. In this method, the normal complement of the resulting approximation is not continuous acros...
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In this paper we are concerned with a domain decomposition method with nonmatching grids for Raviart-Thomas finite elements. In this method, the normal complement of the resulting approximation is not continuous across the interface. To handle such non-conformity, a new matching condition will be introduced. Such matching condition still results in a symmetric and positive definite stiffness matrix. It will be shown that the approximate solution generated by the domain decomposition possesses the optimal energy error estimate.
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