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A method to measure the MTF of digital x‐ray systems
Author(s) -
Sones Richard A.,
Barnes Gary T.
Publication year - 1984
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 - 10.1118/1.595493
Subject(s) - imaging phantom , optical transfer function , fourier transform , measure (data warehouse) , optics , pixel , iterative reconstruction , nyquist frequency , aliasing , magnification , medical imaging , physics , computer science , undersampling , computer vision , artificial intelligence , filter (signal processing) , quantum mechanics , database
A method has been devised to accurately measure the modulation transfer function (MTF) of digital x‐ray systems up to and, for undersampled systems, beyond the pixel Nyquist frequency ( f N ). A phantom consisting of an array of parallel tungsten or similar wires is imaged, and discrete Fourier transforms of rows of pixel values are computed. Under suitable conditions of phantom orientation, wire diameter, wire spacing, and image magnification, the envelope of the modulus of the mean Fourier transform represents the system MTF. Experimental results extending beyond f N are presented for an undersampled prototype digital chest x‐ray system and shown to be in reasonable agreement with predicted values. Employment of the method with other digital imaging modalities [i.e., computerized tomography (CT) scanners and nuclear magnetic resonance (NMR) units] is also discussed as well as error considerations and practical problems in implementing the method.