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Quantitative characterization of edge enhancement in phase contrast x‐ray imaging
Author(s) -
Monnin P.,
Bulling S.,
Hoszowska J.,
Valley J.F.,
Meuli R.,
Verdun F. R.
Publication year - 2004
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 - 10.1118/1.1755568
Subject(s) - optics , phase contrast imaging , detector , image resolution , phase (matter) , holography , edge enhancement , interference (communication) , physics , refraction , resolution (logic) , beam (structure) , energy (signal processing) , materials science , pixel , medical imaging , amplitude , image processing , phase contrast microscopy , image (mathematics) , channel (broadcasting) , quantum mechanics , artificial intelligence , computer science , medicine , electrical engineering , engineering , radiology
The aim of this study was to model the edge enhancement effect in in‐line holography phase contrast imaging. A simple analytical approach was used to quantify refraction and interference contrasts in terms of beam energy and imaging geometry. The model was applied to predict the peak intensity and frequency of the edge enhancement for images of cylindrical fibers. The calculations were compared with measurements, and the relationship between the spatial resolution of the detector and the amplitude of the phase contrast signal was investigated. Calculations using the analytical model were in good agreement with experimental results for nylon, aluminum and copper wires of 50 to 240 μm diameter, and with numerical simulations based on Fresnel–Kirchhoff theory. A relationship between the defocusing distance and the pixel size of the image detector was established. This analytical model is a useful tool for optimizing imaging parameters in phase contrast in‐line holography, including defocusing distance, detector resolution and beam energy.