Shadow Effects for Representing Hovering-and-Contact States of a Projected Hand in Spatial Augmented Reality

By projecting a user-controllable computer graphics (CG) hand into real-world space, users can interact with out-of-reach objects by pointing or touching them using the projected CG hand (referred to as the projected hand). However, due to the nature of projection, the projected hand cannot appear to hover in mid-air. This study proposes a method that represents a shadow of the projected hand and dynamically alters its appearance based on user input. This allows users to perceive whether the projected hand is hovering or in contact with an object. A user study suggests that the proposed shadow effect effectively enhances the perception of the projected hand’s hovering state.