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Proceedings Paper

System analysis of x-ray-sensitive CCDs and adaptive restoration of intraoral radiographs
Author(s): Burkhard Peters; Dietrich Meyer-Ebrecht; Thomas Martin Lehmann; Walter Schmitt
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Paper Abstract

An adaptive Wiener-filter image restoration approach is being described. It is exemplarily applied to intraoral radiographs generated by two x-ray-sensitive CCDs, one having an additional scintillator screen. The devices' MTFs were determined by means of a slightly angulated slit according to DIN 6867/2. Noise power spectra at various exposures were measured and decomposed into quantum and detector noise with respect to the signal and noise model. Both noise power levels were proportional to the incident exposure. Wiener filters for high, low and medium exposures were designed. Weight tables for superpositions of these filters were calculated by minimizing the mean square errors between the superposition MTFs and Wiener filter MTFs for arbitrary exposures. The pixelwise weights depending on the local mean were calculated after a preceding lowpass filtering. The final restored images were composed from spatially invariant filtered images generated by 2D-IIR filtering. The results indicate that the presented adaptive restoration method is a promising approach with regard to both image quality and processing speed demands.

Paper Details

Date Published: 16 April 1996
PDF: 12 pages
Proc. SPIE 2710, Medical Imaging 1996: Image Processing, (16 April 1996); doi: 10.1117/12.237947
Show Author Affiliations
Burkhard Peters, Technical Univ. Aachen (Germany)
Dietrich Meyer-Ebrecht, Technical Univ. Aachen (Germany)
Thomas Martin Lehmann, Technical Univ. Aachen (Germany)
Walter Schmitt, Technical Univ. Aachen (Germany)

Published in SPIE Proceedings Vol. 2710:
Medical Imaging 1996: Image Processing
Murray H. Loew; Kenneth M. Hanson, Editor(s)

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