Marking the Virtual: Exploring Visual Indicators for Distinguishing Physical and Virtual Objects in Augmented Reality

Abstract

As Augmented Reality (AR) applications and their respective virtual components approach photorealism, users are challenged to distinguish physical objects from virtually rendered ones, which can undermine trust in the environment and lead to interaction errors. We address this challenge by introducing three indicators that mark virtual content to support reliable physical-virtual discrimination. Since photorealistic virtual content is still hard to achieve in real-time AR, we induce ambiguity instead by applying a matched Sobel edge-detection stylization to both the passthrough view and the virtual objects. We evaluated the indicators in a user study (N=20) where participants classified objects in an AR environment as either physical or virtual. Our results show that a salient hovering cue significantly improved confidence-weighted classification accuracy over the baseline and the transparency indicator, while it did not differ significantly from an outline. However, misclassifications still occurred for all indicators, suggesting that current designs are not fail-safe. These results give first indications on how users of AR applications could be informed about the physicality and virtuality of components once indistinguishable by the human eye alone.