McEwen, JD;
Price, MA;
(2019)
Scale-discretised ridgelet transform on the sphere.
In:
Proceedings of the 2019 27th European Signal Processing Conference (EUSIPCO).
IEEE: A Coruna, Spain.
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Abstract
We revisit the spherical Radon transform, also called the Funk-Radon transform, viewing it as an axisymmetric convolution on the sphere. Viewing the spherical Radon transform in this manner leads to a straightforward derivation of its spherical harmonic representation, from which we show the spherical Radon transform can be inverted exactly for signals exhibiting antipodal symmetry. We then construct a spherical ridgelet transform by composing the spherical Radon and scalediscretised wavelet transforms on the sphere. The resulting spherical ridgelet transform also admits exact inversion for antipodal signals. The restriction to antipodal signals is expected since the spherical Radon and ridgelet transforms themselves result in signals that exhibit antipodal symmetry. Our ridgelet transform is defined natively on the sphere, probes signal content globally along great circles, does not exhibit blocking artefacts, supports spin signals and exhibits an exact and explicit inverse transform. No alternative ridgelet construction on the sphere satisfies all of these properties. Our implementation of the spherical Radon and ridgelet transforms is made publicly available. Finally, we illustrate the effectiveness of spherical ridgelets for diffusion magnetic resonance imaging of white matter fibers in the brain
Type: | Proceedings paper |
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Title: | Scale-discretised ridgelet transform on the sphere |
Event: | 2019 27th European Signal Processing Conference (EUSIPCO) |
Location: | A Coruna, SPAIN |
ISBN-13: | 978-9-0827-9703-9 |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.23919/EUSIPCO.2019.8903034 |
Publisher version: | https://doi.org/10.23919/EUSIPCO.2019.8903034 |
Language: | English |
Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
Keywords: | Harmonic analysis, spheres, spherical Radon transform, Funk Radon transform, spherical wavelets, spherical ridgelets. |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10171093 |
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