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Proceedings Paper

Light photon equalization for laser film digitizers
Author(s): Yoshiyuki Ishimitsu; H. K. Huang
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Paper Abstract

A new technique to digitize X-ray radiographs was investigated. This technique is based on the principle of light photon equalization (LPE). In this method, the light source is modulated so that the dynamic range of the transmitted light into a photo-detector is precisely controlled to obtain improved signal-to-noise ratio. The modulation of the light source is derived from a smoothed image of the original. The final output digital image is reconstructed by multiplying the modulation function and the resultant LPE image. The LPE was implemented in a laser film digitizer as a prototype. The results show that, although the dynamic range of X-ray films is about 104:1, the range of the transmission light into a photo detector was reduced to 102:1 with this technique. Also the SNR improved by maximum factor of five in the lung area of a digitized chest radiograph.

Paper Details

Date Published: 1 May 1994
PDF: 11 pages
Proc. SPIE 2163, Medical Imaging 1994: Physics of Medical Imaging, (1 May 1994); doi: 10.1117/12.174262
Show Author Affiliations
Yoshiyuki Ishimitsu, Univ. of California/San Francisco (United States)
H. K. Huang, Univ. of California/San Francisco (United States)


Published in SPIE Proceedings Vol. 2163:
Medical Imaging 1994: Physics of Medical Imaging
Rodney Shaw, Editor(s)

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