A Unified Approach to the Performance of Photographic Film, Television Pickup Tubes, and the Human Eye<!--<xref ref-type="other" rid="fn1-10.5594_J12772">*</xref>-->

Abstract

The picture pickup devices film, television pickup tube, and eye are subject ultimately to the same limitations in performance imposed by the discrete nature of light flux. The literature built up around each of these devices does not reflect a similar unity of terminology. The present paper is exploratory and attempts a unified treatment of the three devices in terms of an ideal device. The performance of the ideal device is governed by the relation <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$$scene\ brightness=constant {(signal\hbox{-}to\hbox{-}noise\ ratio)^{2}\over picture\ element area\times quantum\ efficiency}$$</tex> — The three devices are shown to approximate this type of performance sufficiently well to use it as a guide in treating their common problems. Simple criteria are derived for characterizing the performance of any one device as well as for comparing the performance of different devices. For example, quantum efficiency is used to measure sensitivity; the signal-to-noise ratio, associated with a standard element area, is used to measure both resolution and half-tone discrimination. The half-tone discrimination of the eye governs the visibility of “noise” in the reproduced picture and, in particular, requires that pictures be photographed or picked up at increased scene brightness when the brightness of the reproduction is increased. The observation and interpretation of visual “noise” are discussed.