STUDIES OF DISPLAY SYMBOL LEGIBILITY. PART 9. THE EFFECTS OF RESOLUTION, SIZE, AND VIEWING ANGLE OF LEGIBILITY
Donald A. Shurtleff, M Marsetta, Diana J. Showman · 1966
Abstract : An investigation was made to determine the visual sizes required for the identification of standard and revised Leroy alphanumerics, which were televised at resolutions of 10, 8, and 6 lines per symbol height. The visual size needed for 99-percent identification accuracy was similar for resolutions of 10 and 8 lines, but a significantly larger visual size was required for symbols resolved by 6 lines. There were no significant differences in visual sizes required for identification of standard versus revised Leroy symbols at any value of resolution. The findings were used to calculate the effective area for viewing televised symbols.