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.

1. Introduction

Mobility has become an important topic in many perspectives. Computers have become portable and mobile nowadays. They facilitate a distributed, location-independent information access for many applications. But using computers outdoors leads to high demands on the display technology. Environmental outdoor conditions, e.g. varying lighting conditions (day, night, sunlight, etc.) conditions and altering background textures (sky, vegetation, building, etc.), differ from standard desktop workplaces. Therefore, information access and visualization are challenging issues for Human Computer Interaction (HCI). In order to design an ergonomic HCI for outdoor applications the adequate consideration of these characteristics is essential.