2D directional ramp filter
Résumé
Usual tomographic reconstruction methods start by filtering projections before backpro-jecting the data. In some cases, inverting the filtering and the backprojection steps can be useful to preserve spatial information. In this paper, an intermediate between a filter-backproject and a backproject-filter approach is proposed, based on the extension of the usual ramp filter to two dimensions. To this end, an expression for a band-limited 2D version of the ramp filter is derived. We have tested this filter on simulated X-ray CT projections of a Shepp-Logan phantom and on proton CT list-mode data. We accurately reconstructed the X-ray CT and the proton CT data, although the reconstruction can be slightly noisier than a standard filtered backprojection in some cases. A slight improvement of the spatial resolution of proton CT images reconstructed with this 2D filter has been observed.
Domaines
Imagerie médicaleOrigine | Fichiers produits par l'(les) auteur(s) |
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