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Proceedings Paper

Image Noise And Smoothing In Computed Tomography (CT) Scanners
Author(s): Peter M. Joseph
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Paper Abstract

The question of what spatial frequency response gives optimum image quality in computed tomography (CT) images is studied. We have developed a technique for smoothing these images by using a modified back projection filter with attenuated high frequency response. The results are images with a blurred appearance but dramatically reduced image noise. On processing raw data from the EMI head scanner in this way, grey and white matter distributions are clearly visualized with no increase in radiation dose. These results are analyzed in terms of the Weiner spectrum and correlation properties of CT noise. In particular, a "noise equivalent aperture" is defined in a way analogous to that of Shade. It is shown that the prediction of the simple Rose model of noise sampling can not explain the improvement produced by smoothing, even when the correlated character of the noise is taken into account.

Paper Details

Date Published: 27 December 1977
PDF: 8 pages
Proc. SPIE 0127, Application of Optical Instrumentation in Medicine VI, (27 December 1977); doi: 10.1117/12.955913
Show Author Affiliations
Peter M. Joseph, Columbia-Presbyterian Medical Center (United States)


Published in SPIE Proceedings Vol. 0127:
Application of Optical Instrumentation in Medicine VI
Joel E. Gray; William R. Hendee, Editor(s)

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