"Subpixel smoothing by floating grids for ring artifact reduction in fan-beam tomography"
Pickalov V.V.

The distinctions between the artifacts of the tomographic data acquisition systems with parallel and fan-beam geometry are studied. A new method for suppressing such artifacts on the basis of subpixel smoothing by floating grids is proposed. A non-iterative algorithm based on the classical Shepp-Logan method of filtered back-projection with random shifts (within fractions of a pixel) of each detector element or each pixel of a tomogram is developed. According to the results of mathematical simulation using a variety of models, it is shown that the level of ring artifacts can be reduced by subpixel smoothing comparable to the existing methods of artifact suppression.

Keywords: inverse problems, gas flow tomography, numerical algorithms, fan-beam tomography, tomogram artifacts, subpixel smoothing, Shepp-Logan filter.

  • Pickalov V.V. – Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch of Russian Academy of Sciences; Institutskaya ulitsa 4/1, Novosibirsk, 630090, Russia; Dr. Sci., Principal Scientist, e-mail: pickalov@itam.nsc.ru