title: Analytical formula for two-dimensional ring artefact suppression.
abstract: Ring artefacts are the most disturbing artefacts when reconstructed volumes are segmented. A lot of effort has already been put into better X-ray optics, scintillators and detectors in order to minimize the appearance of these artefacts. However, additional processing is often required after standard flat-field correction. Several methods exist to suppress artefacts. One group of methods is based on minimization of the Tikhonov functional. An analytical formula for processing of a single sinogram was developed. In this paper a similar approach is used and a formula for processing two-dimensional projections is found. Thus suppression of ring artefacts is organized as a two-dimensional convolution of `averaged' projections with a given filter. Several approaches are discussed in order to find elements of the filter in a faster and accurate way. Examples of experimental datasets processed by the proposed method are considered.
authors: Henry Moseley X-ray Imaging Facility, Photon Science Institute, Alan Turing Building, The University of Manchester, Manchester M13 9PL, UK.
authors: Valeriy
authors: V
authors: Titarenko
keywords: Tikhonov functional; X-ray tomography; convolution; filter; ill-posed problem; ring artefacts