Image restoration in computed tomography: estimation of the spatially variant point spread function

Author

Rathee, Satyapal ; Koles, Zoly J. ; Overton, T.R.

Author_Institution

Dept. of Appl. Sci. in Med., Alberta Univ., Edmonton, Alta., Canada

Volume

11

Issue

4

fYear

1992

fDate

12/1/1992 12:00:00 AM

Firstpage

539

Lastpage

545

Abstract

An indirect method for determining the point-spread-function (PSF) in computed tomography (CT) is described. Unlike experimental techniques in which a resolution phantom is scanned to obtain the system PSF, the approach estimates the parameters of a model which describes the two-dimensional X-ray beam profile at each point as a convolution of the appropriately scaled focal spot intensity and detector sensitivity distributions. The model was validated by experimental measurement of the focal spot intensity distribution. Using known X-ray beam profiles, the PSF of a CT scanner can be derived by simulating the data collection process and applying conventional image reconstruction techniques. Visual comparison of directly measured and computed PSFs reveals an asymmetry resulting from misregistration of the phantom wires and the image grid

Keywords

computerised tomography; medical diagnostic computing; medical image processing; 2D X-ray beam profile; computed tomography image restoration; data collection process; detector sensitivity; focal spot intensity; image grid; image reconstruction; indirect method; misregistration; model parameters; phantom wires; spatially variant point spread function; Computational modeling; Computed tomography; Convolution; Image reconstruction; Image restoration; Imaging phantoms; Parameter estimation; X-ray detection; X-ray detectors; X-ray imaging;

fLanguage

English

Journal_Title

Medical Imaging, IEEE Transactions on

Publisher

ieee

ISSN

0278-0062

Type

jour

DOI

10.1109/42.192689

Filename

192689