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Proceedings Paper

Restoration Of Radiographs Using A Spatially Variant Filter
Author(s): Piet W. Verbeek; C.Carl Jaffe
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Paper Abstract

Various components of the x-ray imaging process contribute differing forms of degradation. One of the most significant sources of blur is object scatter which cannot be fully eliminated by grids and often contributes more than 60% of the final image exposure. Because the amount of scatter varies locally as a function of attenuation, the low pass filtering which this blurring creates is spatially variant, being most severe in the most attenuated areas (lowest density - most translucent parts) of the image. By taking advantage of this density dependent property we have devised a technique which restores high frequencies only in low, but not in high density areas. The method first creates a high frequency Laplacian filtered version of the original which produces reduced and enhanced high frequency amplitude in originally dark and translucent areas respectively. This high frequently image is then multiplied by a low-pass version of the original image. By then adding the product image to the original a final result is obtained in which only the translucent areas of the image receive significant high frequency restoration. The technique is capable of rapid implementation and can be additive with image processing methods aimed at other, less spatially variant sources of blur.

Paper Details

Date Published: 3 August 1984
PDF: 6 pages
Proc. SPIE 0515, Medical Images and Icons, (3 August 1984); doi: 10.1117/12.964752
Show Author Affiliations
Piet W. Verbeek, Yale University (United States)
C.Carl Jaffe, Delft University of Technology (Netherlands)

Published in SPIE Proceedings Vol. 0515:
Medical Images and Icons
Andre J. Duerinckx; Murray H. Loew; Judith M. S. Prewitt, Editor(s)

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