CT filtration aliasing artifacts

Author

Crawford, Carl R.

Author_Institution

GE Med. Syst., Milwaukee, WI, USA

Volume

10

Issue

1

fYear

1991

fDate

3/1/1991 12:00:00 AM

Firstpage

99

Lastpage

102

Abstract

Two methods for filtering computerized tomography (CT) projections for the filtered backprojection reconstruction algorithm are evaluated. The methods are based on derivations made in the spatial and Fourier domains. The Fourier method of filtration produces images with DC shifts and low-frequency shading. The spatial method does not generate similar artifacts. It is shown that the artifacts result because of aliasing artifacts that arise when a spatial waveform with infinite extent is sampled in the Fourier domain. It is also shown that it is possible to connect the artifacts generated with the Fourier method by replacing the DC and the first two frequency components with the corresponding terms from the discrete Fourier transforms of the filter used in the spatial method

Keywords

computerised tomography; CT filtration aliasing artifacts; Fourier method; LF shading; computerized tomography projections; filtered backprojection reconstruction algorithm; medical diagnostic imaging; spatial waveform; Computed tomography; DC generators; Equations; Filters; Filtration; Fourier transforms; Frequency response; Image reconstruction; Image sampling; Sampling methods;

fLanguage

English

Journal_Title

Medical Imaging, IEEE Transactions on

Publisher

ieee

ISSN

0278-0062

Type

jour

DOI

10.1109/42.75616

Filename

75616