An Analysis of Film Granularity in Television Reproduction: Reprint of BBC Engineering Monograph

The transfer of emulsion granularity in a television system when film is the picture source is considered in some detail using the Wiener spectrum of the film-grain to describe its near-random statistical properties. The modifying effects of some basic parameters associated with television film-scanning and the subsequent processing of the generated video signal are discussed, and illustrated by numerical examples based on the measured Wiener spectra of several commonly-used black-and-white cine-film emulsions. — The differences in the character and magnitude of the granularity obtained, in the final display, due to the several methods and processes employed in the various television applications of film, are examined. Displayed granularity curves are deduced for each of four processes, by selecting appropriate emulsions and by assuming specific processing conditions considered to be representative of operational practice. — After discussing briefly several important factors associated with the visibility of the displayed granularity, an attempt is made to establish, from existing experimental evidence, realistic thresholds of perceptibility in terms of the standard deviation of luminance in the display. Finally, the probable subjective rating, on a six-point scale, of the displayed granularity is deduced for the specific examples representing the four main processes mentioned earlier.

Print ISSN

0361-4573

Published

1964-12

Content type

Original Research

DOI

10.5594/J15384