The visual resolution of a grating depends upon the criterion chosen by the observer. Responding to the slightest change in appearance from a uniform unresolved grating leads to a low minimum angle of resolution but it is a false resolution. The results obtained when indicating the orientation of the grating and when the lines are just seen as parallel lines are significantly different from those arrived at with the criterion of a slightest change of appearance. It is concluded that the most valid criterion is to request S to indicate the orientation of the grating.
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References
1.
ByramG. M.The physical and photochemical basis of visual resolving power. Journal of the Optical Society of America, 1944, 34, 718–738.
2.
CampbellF. W.KulikowskiJ. J.LevinsonJ.The effect of orientation on the visual resolution of gratings. Journal of Physiology, 1966, 187, 427–436.
3.
FreemanR. D.MitchellD. E.MillodotM.A neural effect of partial visual deprivation in humans. Science, 1972, 175, 1384–1386.
4.
HelmholtzH. V.Physiological optics. New York: Optical Society of America, 1924. Vol. 2. (Reprinted by Dover, 1962).
5.
Le GrandY.Form and space vision. Bloomington: Indiana Univer. Press, 1967.
6.
LeibowitzH.Some observations and theory on the variation of visual acuity with the orientation of the test object. Journal of the Optical Society of America, 1953, 43, 902–905.
7.
ShlaerS.The relation between visual acuity and illumination. Journal of General Physiology, 1937, 21, 165–188.
8.
WestheimerG.Visual acuity. Annual Review of Psychology, 1965, 16, 359–380.
