Running head: The Effects of Direct and Global Illumination on Presence in AR The Effects of Direct and Global Illumination on Presence in Augmented Reality

In this paper we present an experiment, which was designed and conducted with the goal to study the effect of lighting on the sense of presence in Augmented Reality. We compared presence ratings between global illumination rendering and direct illumination and asked study participants to judge which of the shown objects are virtual and which ones are real. Thirty people participated in a within-group experiment. A set of questionnaires was used to measure the sense of presence, perception of realism and the rate of interpretation of virtual objects as real ones with both global and direct illumination conditions. The results of our experiment show that global illumination rendering increases the sense of presence in comparison to direct illumination and that there is a correlation between perception of realism and feeling of presence in augmented reality. We discuss the major differences between real and virtual objects as observed by the users and the categories of important features for visual realism in Augmented Reality.