title: Talbot-Lau X-ray phase contrast for tiling-based acquisitions without reference scanning.
abstract: OBJECTIVE
  Grating-based Talbot-Lau interferometers are a popular choice for phase-contrast X-ray acquisitions. Here, an air reference scan has to be acquired prior to an object scan. This particularly complicates acquisition of large objects: large objects are tiled into multiple scans due to the small field of view of current gratings. However, phase reference drifts occurring between these scans may require to repeatedly move the object in and out of the X-ray beam to update the reference information.
  
  
  METHODS
  We developed an image processing technique that completely removes the need for phase reference scans in tiled acquisitions. We estimate the reference from object scans using a tailored iterated robust regression, using a novel efficient optimizer.
  
  
  RESULTS
  Our evaluation indicates that the estimated reference is not only close to the acquired reference but also improves the final image quality. We hypothesize that this is because we mitigate errors that are introduced when actually acquiring the reference phase.
  
  
  CONCLUSIONS
  Phase-contrast imaging of larger objects may benefit from computational estimation of phase reference data due to reduced scanning complexity and improved image quality.
authors.affiliation: Pattern Recognition Lab, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 3, 91058, Erlangen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kaeppler
authors.affiliation: Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, 91058, Erlangen, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Seifert
authors.affiliation: Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, 91058, Erlangen, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Horn
authors.affiliation: Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, 91058, Erlangen, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Pelzer
authors.affiliation: Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, 91058, Erlangen, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Rieger
authors.affiliation: Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, 91058, Erlangen, Germany.
authors.forename: Thilo
authors.initials: T
authors.lastname: Michel
authors.affiliation: Pattern Recognition Lab, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 3, 91058, Erlangen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Maier
authors.affiliation: Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, 91058, Erlangen, Germany.
authors.forename: Gisela
authors.initials: G
authors.lastname: Anton
authors.affiliation: Pattern Recognition Lab, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 3, 91058, Erlangen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Riess
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted; D007368:Interferometry; D011877:Radionuclide Imaging; D014965:X-Rays
keywords: grating interferometer; phase-contrast; reference image; x-ray imaging