The Effect of Rotation on Legibility of Dot-Matrix Characters
Technical memo. (Final)
HUMAN ENGINEERING LAB ABERDEEN PROVING GROUND MD
Pagination or Media Count:
When dot-matrix characters are rotated, as may be in a moving map display, their dot-matrix patterns are distorted and their legibility is thus affected. In this experiment, 16 subjects performed a random search task in which they were asked to look for a target in a random character pattern. The independent variables were a the direction clockwise or counterclockwise, b the angle of stimulus image rotation, and c the target characters distance from the center of the screen, which was also the center of rotation. The dependent variables were response time and response correctness. Significant effects were found for the angle of rotation, the target characters distance from the center, and the target character. The results indicate that a no angle-dependent mechanism is involved in performing this task and the angle of rotation influences recognition mainly through the distortion of dot-matrix patterns b the target characters radial distance from the center of the screen is the determining factor for search time, while the x and y coordinates of the target contributed to dot-matrix pattern distortion and c the target characters interacted differently with the angle and distance factors to determine the extent of distortion and their legibility. Means to quantify the extent of distortion are discussed and the direction for future research is suggested.
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