The effect of rotation on legibility of dot-matrix characters

Abstract

<p>When dot-matrix characters are rotated, as might be the case 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 the direction (clockwise or counterclockwise) and the angle of stimulus image rotation, and the target character's distance from the center of screen, which was also the center of rotation; the dependent variables were response time and response correctness.</p> <p> Significant effects were found in the angle of rotation, the target character's distance from the center, and the target character. The results indicate that (1) 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, (2) the target character's (radial) distance from the center of screen is the determining factor for search time, while the x and y coordinates of the target contributed to dot-matrix pattern distortion, and (3) the target characters interacted differently with the angle and distance factors to determine the extent of distortion and their legibility.</p> <p>Means to quantify the extent of distortion were discussed and the direction for future research is offered.</p>