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Measurement of the presampling modulation transfer function of film digitizers using a curve fitting technique
Author(s) -
Yin FangFang,
Giger Maryellen L.,
Doi Kunio
Publication year - 1990
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 - 10.1118/1.596463
Subject(s) - optical transfer function , curve fitting , optics , transfer function , gaussian function , nyquist frequency , scanner , residual , exponential function , fourier transform , root mean square , gaussian , physics , algorithm , computer science , mathematics , computer vision , mathematical analysis , statistics , electrical engineering , filter (signal processing) , quantum mechanics , engineering
A curve fitting technique combined with an angulated slit image has been developed for the measurement of the presampling modulation transfer function (MTF) of film digitizers. The noisy line spread functions (LSFs) acquired from an angulated slit image are fitted using a combination of two functions by means of a nonlinear least‐square fitting technique. The parameters in the model function for each LSF are obtained by minimizing the residual root mean square (RMS), and then averaged over all the LSF fittings. The resulting analytical function is representative of the continuous presampled LSF. We have found that a combination of Gaussian and exponential functions provides a good fit to the LSFs obtained with film digitizers. The corresponding analytical Fourier transformation of the model function yields the presampling MTF, without Nyquist frequency limitation. Measurements of spatial resolution properties using this method were performed for two laser scanners and an optical drum scanner.