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Experimental validation of the Wigner distributions theory of phase‐contrast imaging
Author(s) -
Donnelly Edwin F.,
Price Ronald R.,
Pickens David R.
Publication year - 2005
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1876552
Subject(s) - phase contrast imaging , contrast (vision) , phase (matter) , optics , measure (data warehouse) , physics , mathematics , fresnel diffraction , statistical physics , diffraction , phase contrast microscopy , computer science , quantum mechanics , database
Recently, a new theory of phase‐contrast imaging has been proposed by Wu and Liu [Med. Phys. 31, 2378–2384 (2004)]. This theory, based upon Wigner distributions, provides a much stronger foundation for the evaluation of phase‐contrast imaging systems than did the prior theories based upon Fresnel‐Kirchhoff diffraction theory. In this paper, we compare results of measurements made in our laboratory of phase contrast for different geometries and tube voltages to the predictions of the Wu and Liu model. In our previous publications, we have used an empirical measurement (the edge enhancement index) to parametrize the degree of phase‐contrast effects in an image. While the Wu and Liu model itself does not predict image contrast, it does measure the degree of phase contrast that the system can image for a given spatial frequency. We have found that our previously published experimental results relating phase‐contrast effects to geometry and x‐ray tube voltage are consistent with the predictions of the Wu and Liu model.