Text readability in augmented reality: a multivocal literature review

Augmented reality (AR) is making its way into many sectors. Its rapid evolution in recent years has led to the development of prototypes demonstrating its effectiveness. However, to be able to push these prototypes to the scale of fully usable applications, it is important to ensure the readability of the texts they include. To this end, we conducted a multivocal literature review (MLR) to determine the text parameters a designer can tune, as well as the contextual constraints they need to pay attention to, in relation to Optical See-Through (OST) and Video See-Through (VST) displays. We also included guidelines from device manufacturing and game engines sites to compare the current state of research in the academic and industrial worlds. The results show that parameters pertaining more to letter legibility have been extensively studied (e.g., color and size), while those pertaining to the whole text still require further research (e.g., alignment or space between lines). The former group of parameters, and their associated constraints, were assembled in the form of two decision trees to facilitate implementation of AR applications. Finally, we also concluded that there was a lack of alignment between academic and industrial recommendations.