Visual Occlusion and User Experience in Augmented Reality Post-Stroke Therapy

Abstract

The objective of this study is to investigate the effect of visual occlusion on users’ perception in a prototype augmented reality post stroke therapy system. A review of the literature shows a need for affordable therapy systems, and that the effects of visual occlusion on user experience had not previously been investigated. An upper limb rehabilitation exercise was implemented using the Kinect motion controller to enable depth sensing, spatial interaction with virtual objects, and correct visual occlusion of the upper limb and virtual elements of the augmented reality scene. Thirty participants evaluated the exercise under three different occlusion modes representative of those seen in augmented reality systems: correct visual occlusion, virtual always occludes real, and semi-transparency. The analysis of their reported experience showed that correct visual occlusion was the preferred mode for performing the task, providing a more tangible and realistic interactive experience, and that the therapy task was easy and satisfying to perform using the prototype system. The results of the experiment are encouraging, and suggest that correctly resolving occlusion should be a key consideration for future work in the field of augmented reality for physical rehabilitation.