FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-68/20

Title and Subtitle: Two-flash thresholds as a function of flash luminance and area

Report Date: September 1968

Authors: Lewis MF

Abstract: The recent use of strobe lights in aviation suggests the possibility of using temporal patterns of short duration flashes as information-carrying signals. Under night flight conditions, two-flash thresholds were obtained using a two-interval, temporal forced-choice technique with foveally fixated circular targets varying in luminance and area. For all subjects the results replicated a previous finding that two-flash thresholds are a negatively accelerated function of flash luminance, but the function was shown to be dependent on area, a greater threshold change occurring at smaller areas. Two-flash thresholds were also found to be a decreasing function of stimulus area, with the greatest threshold change occurring at low luminances.

Key Words: Visual perception, lighting equipment, aviation safety, optical communications, stroboscopes, information theory, response, eye, stimulaion, thresholds

No. of Pages: 10