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Journal articles

Tiny changes in tomographic system matrices can cause large changes in reconstruction quality

Feriel Khellaf 1 Rolf Clackdoyle 1 Simon Rit 2 Laurent Desbat 1 
1 TIMC-GMCAO - Gestes Medico-chirurgicaux Assistés par Ordinateur
TIMC - Translational Innovation in Medicine and Complexity / Recherche Translationnelle et Innovation en Médecine et Complexité - UMR 5525
2 Imagerie Tomographique et Radiothérapie
CREATIS - Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé
Abstract : This paper studies the impact of tiny changes in region-of-interest (ROI) tomography system matrices on the variance of the reconstructed ROI. In small-scale and medium-scale examples, the variance in the reconstructed ROI was estimated for different system matrices. The results revealed a striking and counterintuitive phenomenon: a tiny change in the system matrix can dramatically affect the variance of the ROI estimate. In one of our examples, a decrease of 0.1% in one element out of hundreds of thousands of the system matrix resulted in a systematic reduction of the variance inside the ROI, and by a factor of 5 to 10 for some pixels. Our results agree with a recently proven theorem about the ability of additional measurements to reduce the variance in ROI tomography.
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Submitted on : Monday, April 11, 2022 - 9:59:18 PM
Last modification on : Thursday, May 12, 2022 - 2:55:59 PM


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Feriel Khellaf, Rolf Clackdoyle, Simon Rit, Laurent Desbat. Tiny changes in tomographic system matrices can cause large changes in reconstruction quality. Physics in Medicine and Biology, IOP Publishing, inPress, ⟨10.1088/1361-6560/ac65d5⟩. ⟨hal-03637819⟩



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