Sage Journals: Discover world-class research

Abstract

Mariners frequently have trouble distinguishing lighted aids to navigation in areas with a high density of background lights. The Coast Guard is seeking ways to enhance the conspicuity, or likelihood of being noticed, of these aids. Literature has shown that a flashing light is more conspicuous than one that is steady. To improve conspicuity by determining optimal flash characteristics, we had 20 observers search for a flashing point of light among backgrounds of steady lights on a CRT screen. In single 360-trial sessions, observers indicated which of five screen sectors contained the flashing target, and accuracy and response time were recorded. Targets were flashed at 1, 2, and 3.85 Hz, each at duty cycles of .3, .5, and .8. An ANOVA showed significant effects of frequency, duty cycle, and background light density. Search time increased with number of background lights. Conspicuity improved as frequency increased and as duty cycle decreased.

Get full access to this article

View all access options for this article.

References

Boersema

Zwaga

H. J. G.

Adams

A. S.

(1989). Conspicuity in realistic scenes: An eye-movement measure. Applied Ergonomics, 20, 267–273.

Connors

M. M.

(1975). Conspicuity of target lights: The influence of flash rate and brightness (Report No. NASA TN D-7961). Moffett Field, CA: NASA Ames Research Center.

Gerathewohl

S. J.

(1953). Conspicuity of steady and flashing light signals: Variation of contrast. Journal of the Optical Society of America, 43, 567–571.

Gerathewohl

S. J.

(1954). Conspicuity of flashing light signals of different frequency and duration. Journal of Experimental Psychology, 48, 247–251.

Gerathewohl

S. J.

(1957). Conspicuity of flashing light signals: Effects of variation among frequency, duration, and contrast of the signals. Journal of the Optical Society of America, 47, 27–29.

Katchmar

L. T.

Azrin

N. H.

(1956). Effectiveness of warning lights as a function of flash rate (Technical Memorandum No. 23). Aberdeen Proving Ground, Md.: U. S. Army Human Engineering Laboratory.

Laxar

Benoit

S. L.

(1993). Conspicuity of Aids to Navigation: I. Temporal Patterns for Flashing Lights (Report No. 1187). Groton, CT: Naval Submarine Medical Research Laboratory.

Laxar

Luria

S. M.

(1992, October). Flashing stimuli and viewing discomfort. Poster session presented at the 36th Annual Meeting of the Human Factors Society, Atlanta, GA.

Mandler

M. B.

(1989). Conspicuity of aids to navigation: Extended light sources (Report No. RD&C 03/89). Groton, CT: U.S. Coast Guard Research and Development Center.

10.

Smith

S. L.

Goodwin

N. C.

(1971). Blink coding for information display. Human Factors, 13, 283–290.

11.

Thackray

R. I.

Touchstone

R. M.

(1991). Effects of monitoring under high and low taskload on detection of flashing and coloured radar targets. Ergonomics, 34, 1065–1081.

12.

Van Orden

K. F.

DiVita

Shim

M. J.

(1993). Redundant use of luminance and flashing with shape and color as highlighting codes in symbolic displays. Human Factors, 35, 195–204.

13.

Worthey

J. A.

(1988). Lights of New York Harbor (Report No. NBSIR 88-3807). Gaithersburg, MD: National Bureau of Standards.

The Conspicuity of Flashing Lights as Marine Aids to Navigation

Abstract

Get full access to this article

References