Evaluation of Radiographic Mottle Using a Single Frequency Value of the Psychophysical Wiener Spectrum

Abstract

In radiographs, the Wiener spectral values al low frequency have been used for the evaluation of radiographic mottle. The validity of the psychophysical RMS granularity a,, as a new measure for the evaluation of radiographic mottle was confirmed in our previous paper IJ. Photogr. Sci., 43, 103 (1995)1.

We calculate the density dependence at various frequencies of the Wiener spectrum W(v) and the psychophysical Wiener spectrum W^p(v), which is psycliophysically corrected, and compare with that of σ_p². The density dependence of Wr(v) at a frequency of 2.0 mm ^-1 is in good agreement with that of σ_p². It is therefore possible to evaluate the radiographic mottle using the W/v) value, at a frequency of 2.0 mm ^-1 instead of ap in this example. The time to obtain the density dependence of ap, which requires the measurement of ΔD,_mm, values at many frequencies and integration with respect to frequency, can be reduced using this method.