Abstract

The traditional definition of visibility of a suprathreshold object involves the distance at which it is just seen. Such a definition involves a number of problems: (1) it relies on criterion-uncontrolled psychophysics; (2) the object is taken to its threshold and so is no longer suprathreshold; (3) the site of the object is altered in the task. Practical applications of visual science often seek quantitative specification of target visibility when targets are above threshold. We apply the bootstrap procedure of signal detection theory to document the problems cited and to yield a detectability-based measure of how visible targets are. In ideal conditions the measure has metric properties and is amenable to manipulation based upon parameters known to affect threshold. Use of the new visibility measure is illustrated.

© 1985 Optical Society of America