Abstract

The term hyperacuity refers to visual tasks for which the question asked of the observer is, for example, "Where is the upper line in relation to the bottom one?", as in vernier acuity and stereoacuity. Resolution tasks ask a different question; for example, "Do you see one or two lines?" It is not uncommon in hyperacuity tasks that one can judge relative spatial position to an accuracy of 3 seconds of arc, a visual angle 10 times smaller than the center-to-center spacing of individual foveal cones. This is the basis for the term "hyper"-acuity (Westheimer, 1979).

© 1985 Optical Society of America