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ELEMENT SPECIFIC IMAGE ACQUISITION BY SAMPLING FOURIER COMPONENTS
"... In electron microscopy, elemental information is usually acquired in real space by scanning a focussed probe over the specimen. We think there is a method to acquire elemental maps in Fourier space by sequentially sampling Fourier components. The method is based on the illumination of the specimen w ..."
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In electron microscopy, elemental information is usually acquired in real space by scanning a focussed probe over the specimen. We think there is a method to acquire elemental maps in Fourier space by sequentially sampling Fourier components. The method is based on the illumination of the specimen
TRANSFORM NOISE STATISTICS AND FOURIER COMPONENT ESTIMATION
"... As a first step towards more absolute quantitative procedures for evaluating images, new and better ways are presented of estimating the spacings and complex amplitudes present in the image of a crystalline specimen by examining the peaks in its calculated transform. So that the expected performance ..."
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of the transform noise. The role of image windowing in minimising systematic errors due to interference between different Fourier components is made clear, and the properties of three different windows evaluated; the halfcosine window is recommended as a useful compromise between the (trivial) unit window
Study of Magnetic Fourier Components Effect on Ion Viscosity
"... The influence of the low order rational surface (n, m) = (5, 3) on an ion viscosity and the formation of the radial electric field were investigated by the electrode current sweep biasing with a hot cathode in Tohoku University Heliac (TUHeliac). During the improved mode, the position of the maxim ..."
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of the maximum electric field stayed on the n/m = 5/3 rational surface. After the HL transition the local maxima shifted outward to the plasma periphery of ρ ~ 0.8. The low order magnetic islands were formed resonating the magnetic Fourier components of (n, m) = (5, 3) by external perturbation coils. As widths
The Fourier components of a set of position or density variab...
"... Abstract Collectivedensity variables have proved to be a useful tool in the prediction and manipulation of how spatial patterns form in the classical manybody problem. Previous work has employed properties of collectivedensity variables along with a robust numerical optimization technique to find ..."
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states of directional pair potentials in two dimensions. Our study focuses on directional potentials whose Fourier representations are nonzero on compact sets that are symmetric with respect to the origin and zero everywhere else. We choose to focus on one representative set that has exotic ground
CONSTRAINED DECONVOLUTION BY EXPLICIT CORRECTION OF FOURIER COMPONENTS OF THE UNKNOWN DISTRIBUTION
, 1999
"... SUMMARY: The physical constraints were applied in the problem of deconvolution by explicitly correcting noise affected Fourier components of the unknown distribution. The method gives the constrained estimate optimal in the quadratic sense, i.e. the estimate closest to the exact solution in the Euc ..."
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SUMMARY: The physical constraints were applied in the problem of deconvolution by explicitly correcting noise affected Fourier components of the unknown distribution. The method gives the constrained estimate optimal in the quadratic sense, i.e. the estimate closest to the exact solution
The curvelet transform for image denoising
 IEEE TRANS. IMAGE PROCESS
, 2002
"... We describe approximate digital implementations of two new mathematical transforms, namely, the ridgelet transform [2] and the curvelet transform [6], [5]. Our implementations offer exact reconstruction, stability against perturbations, ease of implementation, and low computational complexity. A cen ..."
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Cited by 404 (40 self)
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central tool is Fourierdomain computation of an approximate digital Radon transform. We introduce a very simple interpolation in Fourier space which takes Cartesian samples and yields samples on a rectopolar grid, which is a pseudopolar sampling set based on a concentric squares geometry. Despite
A Local Algorithm for the Computation of Optic Flow via Constructive Interference of Global Fourier Components
"... A novel Fourierbased technique for the estimation of opticflow fields from image sequences is proposed. In this method, the instantaneous velocities of local image points are inferred directly from the global 3D Fourier components of the image sequence. This is done by selecting those velocities f ..."
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Cited by 3 (3 self)
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A novel Fourierbased technique for the estimation of opticflow fields from image sequences is proposed. In this method, the instantaneous velocities of local image points are inferred directly from the global 3D Fourier components of the image sequence. This is done by selecting those velocities
Response Functions from Fourier Component Variational Perturbation Theory applied to a TimeAveraged
, 1998
"... ABSTRACT: It is demonstrated that frequencydependent response functions can conveniently be derived from the timeaveraged quasienergy. The variational criteria for the quasienergy determines the timeevolution of the wavefunction parameters and the timeaveraged timedependent Hellmann]Feynman th ..."
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Cited by 1 (0 self)
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theory to a Fourier component variational perturbation theory. The generality and simplicity of this approach are illustrated by derivation of linear and higherorder response functions for both exact and approximate wave functions and for both variational and nonvariational wave functions. Examples
Negative refraction makes a perfect lens
 Phys. Rev. Lett
, 2000
"... With a conventional lens sharpness of the image is always limited by the wavelength of light. An unconventional alternative to a lens, a slab of negative refractive index material, has the power to focus all Fourier components of a 2D image, even those that do not propagate in a radiative manner. Su ..."
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Cited by 292 (3 self)
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With a conventional lens sharpness of the image is always limited by the wavelength of light. An unconventional alternative to a lens, a slab of negative refractive index material, has the power to focus all Fourier components of a 2D image, even those that do not propagate in a radiative manner
Results 1  10
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2,571