Granularity of dental X-ray film. Fundamental study of Wiener spectrum measurement.

Abstract

We developed a 16k dots x 100 lines Wiener spectrum measurement system using a microscope-television camera combination. Heretofore, the granularity of film was evaluated from Wiener spectrum using Wiener spectral value in the spatial-frequency independent region obtained by microphotometer as the input device, but this factor is determined by the measurement system and the film emulsion density and there were problems in the evaluation of granularity. Therefore we established a new method for evaluating the granularity from Wiener spectral values in the spatial-frequency independent region through a Wiener spectrum measurement system that utilized a microscope-television camera setup as the input device.