Abstract
This study examined the legibility threshold value for color Chinese characters when presented on optical head-mounted displays (OHMDs) during walking. We used the Minnesota Low Vision Reading test (MNREAD test) to determine character legibility thresholds. A full factorial design was employed, using the following three main factors: hue (0°, 60°, and 120°), saturation (33%, 66%, and 99%), and brightness (33%, 66%, and 99%). Twenty-seven colors were used as experimental colors. The results indicated that the character colors shown on the OHMD with the 0° hue (red color) had a higher character recognition threshold value than characters presented in the 60° (yellow color) and 120° hues (green color). Furthermore, characters presented with higher color saturation had higher character recognition threshold values than those presented with lower color saturation, and characters presented with lower color brightness had higher character recognition threshold values than those presented with higher color brightness. These findings indicate that the hue, saturation, and brightness of character colors on OHMDs must be taken into consideration as they may affect legibility.