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Derivation of large-screen display requirements

Large screen displays are typically viewed from distances which are proportionally greater than smaller CRT displays. In specifying large screen displays, conventional performance standards such as HFS-88-100 must be augmented to consider the effects of visual acuity limitations in the user. Using an expression for the viewer's modulation threshold as a function of angular frequency and luminance presented by Barten, we derive a requirement for screen modulation as a function of observer position. We define a parametric relationship between display contrast ratio and display modulation transfer function which bounds the set of usable values for these parameters. This analysis predicts luminance and resolution requirements often unobtainable from current systems. This analysis is presented in the context of a case study derived from the installation of a large screen display at the Gaston Steam Plant control room of Alabama Power Company. The use of front or rear projection, as well as the implications of the color usage in the displayed images is discussed.