Abstract
Nonlinear diffusion equations have been successfully used for image enhancement by reducing the noise in the image while protecting the edges. In discretized form, the denoising requires the solution of a sequence of linear systems. The underlying system matrices stem from a discrete diffusion operator with large jumps in the diffusion coefficients. As a result these matrices can be very ill-conditioned, which leads to slow convergence for iterative methods such as the Conjugate Gradient method. To speed-up the convergence we use deflation and preconditioning. The deflation vectors are defined by a decomposition of the image. The resulting numerical method is easy to implement and matrix-free. We evaluate the performance of the method on a simulated image and on a measured low-field MR image for various types of deflation vectors.
Original language | English |
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Title of host publication | Numerical Mathematics and Advanced Applications, ENUMATH 2019 - European Conference |
Editors | Fred J. Vermolen, Cornelis Vuik |
Publisher | Springer |
Pages | 459-468 |
Number of pages | 10 |
ISBN (Print) | 978-3-0305-5873-4 |
DOIs | |
Publication status | Published - 2021 |
Event | European Conference on Numerical Mathematics and Advanced Applications, ENUMATH 2019 - Egmond aan Zee, Netherlands Duration: 30 Sept 2019 → 4 Oct 2019 |
Publication series
Name | Lecture Notes in Computational Science and Engineering |
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Volume | 139 |
ISSN (Print) | 1439-7358 |
ISSN (Electronic) | 2197-7100 |
Conference
Conference | European Conference on Numerical Mathematics and Advanced Applications, ENUMATH 2019 |
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Country/Territory | Netherlands |
City | Egmond aan Zee |
Period | 30/09/19 → 4/10/19 |
Bibliographical note
Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-careOtherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.