A comparative study of the sense of presence and anxiety in an invisible marker versus a marker augmented reality system for the treatment of phobia towards small animals

Phobia towards small animals has been treated using exposure in vivo and virtual reality. Recently, augmented reality (AR) has also been presented as a suitable tool. The first AR system developed for this purpose used visible markers for tracking. In this first system, the presence of visible markers warns the user of the appearance of animals. To avoid this warning, this paper presents a second version in which the markers are invisible. First, the technical characteristics of a prototype are described. Second, a comparative study of the sense of presence and anxiety in a non-phobic population using the visible marker-tracking system and the invisible marker-tracking system is presented. Twenty-four participants used the two systems. The participants were asked to rate their anxiety level (from 0 to 10) at 8 different moments. Immediately after their experience, the participants were given the SUS questionnaire to assess their subjective sense of presence. The results indicate that the invisible marker-tracking system induces a similar or higher sense of presence than the visible marker-tracking system, and it also provokes a similar or higher level of anxiety in important steps for therapy. Moreover, 83.33% of the participants reported that they did not have the same sensations/surprise using the two systems, and they scored the advantage of using the invisible marker-tracking system at 5.19±2.25 (on a scale from 1 to 10). However, if only the group with higher fear levels is considered, 100% of the participants reported that they did not have the same sensations/surprise with the two systems, scoring the advantage of using the invisible marker-tracking system at 6.38±1.60 (on a scale from 1 to 10). 1. Introduction This paper presents an augmented reality (AR) invisible marker-tracking system for the treatment of a phobia towards small animals. AR refers to the introduction of virtual content into the real world, that is, the user is seeing an image composed of a real image and virtual elements superimposed over it. A phobia towards small animals has traditionally been treated using exposure in vivo and also using virtual reality (VR) (e.g. Carlin, Hoffman & Weghorst, 1997). Recently, the used of AR was presented as an alternative technology for this type of treatment (Juan et al., 2005; Botella et al., 2005). In that work, visible markers were used for tracking. In this paper, we present a second version of the visible marker-tracking AR system (VMARS) in which markers that are …