You are not currently logged in.
Access JSTOR through your library or other institution:
An Empirical Formula for Visual Search
Bernard O. Koopman
Vol. 34, No. 3 (May - Jun., 1986), pp. 377-383
Published by: INFORMS
Stable URL: http://www.jstor.org/stable/170928
Page Count: 7
You can always find the topics here!Topics: Mathematical constants, Diameters, Experimental data, Luminance, Approximation, Information search, Range searching, Tangents, Asymptotic value, Natural logarithms
Were these topics helpful?See somethings inaccurate? Let us know!
Select the topics that are inaccurate.
Preview not available
This paper presents an empirically derived formula for computing the threshold contrast C for visually detecting distant objects in search situations. The threshold contrast is the value of contrast that produces detection probability 1/2 on a single glimpse of about 1/3 to 1 second in duration. The formula allows one to compute C as a function of background luminance, target angular area A, and an empirically determined constant K. For small A, the formula reduces to Ricco's law, which says that the threshold constrast C, and Area A, are directly proportional for small values of A. The limiting threshold contrast is determined by K. Results of fitting this formula to a set of observational data are shown. The formula provides a useful approximation for determining detection capability for planning visual searches.
Operations Research © 1986 INFORMS