The Sensitivity of Response Measures of Alphanumeric Legibility to Variations in Dot Matrix Display Parameters

This research evaluated the sensitivity of four observer response measures to variations in the character size and dot luminance of a dot matrix display. Specifically, the research determined the sensitivity of recognition accuracy, response time, tachistoscopic recognition accuracy, and threshold visibility. Alphanumeric characters were presented to six subjects in noncontextual form on a variable-parameter CRT display programmed and driven by a minicomputer. Recognition accuracy (percent correct response) was found to be the response measure that is most sensitive to the display parameters of character size and dot luminance. Character size, dot luminance, and viewing distance proved to have consistent and significant effects at viewing distances greater than 1.52 m. At lesser viewing distances, these parameters had little effect. The results suggest that there is no major difference between the display requirements for computer-generated dot matrix displays versus those for conventional CRT displays.