Abstract
In the past, two measures have been used to express the comparative effectiveness of steady and flashing light signals. These are comparative intensities (a) required for threshold; and (b) required for equal apparent brightness above threshold. The two measures agree in showing that the effectiveness of flashing signals is less than that of steady signals, when the intensity of the light phases of the flashing signal equals the intensity of the steady signal. The present study compares steady and flashing light signals with respect to conspicuity, defined as the speed of response to a signal above threshold. For large signal contrasts the conspicuity of steady and flashing signals is approximately equal. For small contrasts the conspicuity of flashing signals is considerably greater. These results suggest that flashing rather than steady signals be used for warning purposes.
© 1953 Optical Society of America
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Siegfried J. Gerathewohl
J. Opt. Soc. Am. 47(1) 27-29 (1957)
Earl Davy
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Thomas R. Corwin
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