Optimal Font Size for Head-Mounted-Displays in Outdoor Applications

Modern mobile IT-systems offer a great potential for various applications and enable a user to work autonomously, to communicate or to retrieve information nearly everywhere. However, displaying information outdoors is still challenging for the system designer. Numerous approaches of Augmented Reality (AR) tend to integrate additional information into the real context of the user's environment. Using this technology outdoors is strongly affected by special environmental conditions like lighting and background textures. These factors differ substantially from indoor and are likely to reduce the recognizing and reading performance, which is important in combination with different font colours. This paper presents an empirical analysis of the influence of background texture and font colour on text recognition performance. N=20 participants took part in the experiments. The results clearly show significant differences to the standards for desktop systems (10pt). Applying the resulting font sizes for outdoor systems will drastically reduce the amount of information that can be displayed.