title: On the use of flat-fields for tomographic reconstruction.
abstract: Seeking for quantitative tomographic images, it is of utmost importance to limit reconstruction artifacts. Detector imperfections, inhomogeneity of the incident beam, as classically observed in synchrotron beamlines, and their variations in time are a major cause of reconstruction bias such as `ring artifacts'. The present study aims at proposing a faithful estimate of the incident beam local intensity for each acquired projection during a scan, without revisiting the process of data acquisition itself. Actual flat-fields (acquired without specimen in the beam) and sinogram borders (when the specimen is present), which are not masked during the scan, are exploited to construct a suited instantaneous detector-wide flat-field. The proposed treatment is fast and simple. Its performance is assessed on a real scan acquired at ESRF ID19 beamline. Different criteria are used including residuals, i.e. difference between projections of reconstruction and actual projections. All confirm the benefit of the proposed procedure.
authors.affiliation: LMT (ENS Cachan/CNRS/Université Paris-Saclay), 61 avenue du Président Wilson, F-94235 Cachan, France.
authors.forename: Clément
authors.initials: C
authors.lastname: Jailin
authors.affiliation: MATEIS (INSA-Lyon/CNRS/Université C. Bernard, Lyon-I), F-69621 Villeurbanne, France.
authors.forename: Jean Yves
authors.initials: JY
authors.lastname: Buffière
authors.affiliation: LMT (ENS Cachan/CNRS/Université Paris-Saclay), 61 avenue du Président Wilson, F-94235 Cachan, France.
authors.forename: François
authors.initials: F
authors.lastname: Hild
authors.affiliation: LMT (ENS Cachan/CNRS/Université Paris-Saclay), 61 avenue du Président Wilson, F-94235 Cachan, France.
authors.forename: Martin
authors.initials: M
authors.lastname: Poncelet
authors.affiliation: LMT (ENS Cachan/CNRS/Université Paris-Saclay), 61 avenue du Président Wilson, F-94235 Cachan, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Roux
keywords: artifact corrections; computed tomography; flat-field normalization