Abstract

The magnitude of a measurement of the noise power spectrum (NPS) of a radiographic screen-film system is affected by the light-scattering properties of the film studied and the optical characteristics of the microdensitometer used to sample the image. To facilitate absolute NPS intercomparisons among laboratories, NPS in terms of instrument density must be converted to diffuse density. Conversion in terms of a Callier Q factor was found to be inadequate due to nonlinearity of the density response of the microdensitometer. By establishing instrument-to-diffuse density characteristic curves for the microdensitometers at two laboratories and correcting the NPS by the square of the slopes of these curves at the density of the image, good agreement was achieved for independent NPS measurements of a given film sample.

© 1982 Optical Society of America

Radiographic screen–film noise power spectrum: variation with microdensitometer slit length

John M. Sandrik and Robert F. Wagner
Appl. Opt. 20(16) 2795-2798 (1981)

Noise power spectrum analysis of a scanning microdensitometer

Phillip C. Bunch and Richard Van Metter
Appl. Opt. 27(16) 3468-3474 (1988)

Analysis of the detective quantum efficiency of a radiographic screen–film combination

Phillip C. Bunch, Kenneth E. Huff, and Richard Van Metter
J. Opt. Soc. Am. A 4(5) 902-909 (1987)

X-ray calibration of Kodak Direct Exposure film

P. D. Rockett, C. R. Bird, C. J. Hailey, D. Sullivan, D. B. Brown, and P. G. Burkhalter
Appl. Opt. 24(16) 2536-2542 (1985)

Method of Measuring Diffuse RMS Granularity

H. C. Schmitt and J. H. Altman
Appl. Opt. 9(4) 871-874 (1970)