An empirical equation for screen MTFs.

An empirical equation is described which accurately fits intensifying-screen MFT data within the accuracy of the MTF measurements. The equation is S (u) = 0.5 erfc[alpha1n(u/u0)]. The equation was fitted to data for 27 intensifying screens. Graphical and numerical results are presented. The maximum standard error was 0.02 and typical standard error was 0.01. Comparisons between results for three experimenters are also presented.