title: Computational calibration method for optical tomography.
abstract: We propose a computational calibration method for optical tomography. The model of the calibration scheme is based on the rotation symmetry of source and detector positions in the measurement setup. The relative amplitude losses and phase shifts at the optic fibers are modeled by complex-valued coupling coefficients. The coupling coefficients can be estimated when optical tomography data from a homogeneous and isotropic object are given. Once these coupling coefficients have been estimated, any data measured with the same measurement setup can be corrected for the relative variation in the data due to source and detector losses. The final calibration of the data for the source and detector losses and the source calibration between the data and the forward model are obtained as part of the initial estimation for reconstruction. The calibration method was tested with simulations and measurements. The results show that the coupling coefficients of the sources and detectors can be estimated with good accuracy. Furthermore, the results show that the method can significantly improve the quality of reconstructed images.
authors.affiliation: Department of Applied Physics, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland. Tanja.Tarvainen@uku.fi
authors.forename: Tanja
authors.initials: T
authors.lastname: Tarvainen
authors.forename: Ville
authors.initials: V
authors.lastname: Kolehmainen
authors.forename: Marko
authors.initials: M
authors.lastname: Vauhkonen
authors.forename: Antti
authors.initials: A
authors.lastname: Vanne
authors.forename: Adam P
authors.initials: AP
authors.lastname: Gibson
authors.forename: Martin
authors.initials: M
authors.lastname: Schweiger
authors.forename: Simon R
authors.initials: SR
authors.lastname: Arridge
authors.forename: Jari P
authors.initials: JP
authors.lastname: Kaipio
mesh_terms: D000465:Algorithms; D002138:Calibration; D019544:Equipment Failure Analysis / Q000379:methods*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041622:Tomography, Optical / Q000295:instrumentation* / Q000379:methods*