Search for dissertations about: "Radon transforms"
Showing result 1 - 5 of 6 swedish dissertations containing the words Radon transforms.
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1. Fast Radon Transforms and Reconstruction Techniques in Seismology
Abstract : The measurements conducted in tomography and seismology typically yield large multidimensional data sets. This in combination with the fact that the data may have an irregular structure makes it computationally prohibitive to use simple reconstruction methods directly. READ MORE
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2. Studies of vector tomography
Abstract : The motivation to study the kind of problems appearing in this thesis has been ultrasound measurements of flows, from which velocity spectra along lines can be determined. These velocity spectra can mathematically be described by a new non-linear transform, here called the Doppler Spectral Transform (DST). READ MORE
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3. Inverse Problems in Tomography and Fast Methods for Singular Convolutions
Abstract : There are two, partially interlaced, themes treated in this thesis; inverse problems of tomographic type and fast and accurate methods for the application of convolution operators. Regarding the first theme, the inverse problem of Doppler tomography is considered and the Doppler moment transform is introduced for that purpose. READ MORE
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4. Topics in geometry, analysis and inverse problems
Abstract : The thesis consists of three independent parts.Part I: Polynomial amoebasWe study the amoeba of a polynomial, as de ned by Gelfand, Kapranov and Zelevinsky. A central role in the treatment is played by a certain convex function which is linear in each complement component of the amoeba, which we call the Ronkin function. READ MORE
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5. The Use of Landweber Algorithm in Image Reconstruction
Abstract : Ill-posed sets of linear equations typically arise when discretizing certain types of integral transforms. A well known example is image reconstruction, which can be modelled using the Radon transform. After expanding the solution into a finite series of basis functions a large, sparse and ill-conditioned linear system arises. READ MORE