An experiment is described whose objective was to determine a set of alphanumeric characters of equal recognizability. Constraints were that the characters be similar in aspect ratio to the conventional tri-bar target, i.e., 5:1, and that they and the surround have a low density difference. Such a set is described, together with the experimental technique and data analysis used by the present authors to evaluate the set. At an alpha risk of 0.10 the set of characters E S 2 3 8 9 was found to have equal recognizability under two varied viewing conditions.
Library of Congress Subject Headings
Visual discrimination; Photographic optics; Resolution (Optics); Visual acuity
Donaldson, Keith C. and Gough, Harry O., "The determination of a set of alphanumeric characters of equal recognizability" (1967). Thesis. Rochester Institute of Technology. Accessed from
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