Evaluation of Drop Shadows for Virtual Object Grasping in Augmented Reality

Area of Science:

• Human-Computer Interaction
• Computer Graphics
• Virtual Reality

Background:

• Exocentric augmented reality (AR) systems present virtual objects from an external viewpoint.
• Accurate grasping of virtual objects is crucial for effective AR interaction.
• Visual cues like drop shadows can potentially enhance user perception and interaction fidelity.

Purpose of the Study:

• To investigate the impact of drop shadows as a visual cue on the usability and accuracy of grasping interactions in monitor-based exocentric AR.
• To quantify the effects of drop shadows on grasp metrics, task completion time, and user perception.

Main Methods:

• Two experimental conditions were compared: grasping with and without drop shadows.
• 1620 grasps of virtual cubes and spheres were analyzed from 30 participants.
• Metrics included Grasp Aperture (GAp), Grasp Displacement (GDisp), completion time, and usability ratings for the Medium Wrap grasp.

Main Results:

• Drop shadows significantly increased the usability of AR grasping interactions.
• Task completion times were significantly decreased with the use of drop shadows.
• User depth estimation of AR object position was significantly improved by drop shadows.

Conclusions:

• Drop shadows are an effective visual cue for enhancing usability and efficiency in AR grasping.
• While improving depth perception, drop shadows do not resolve challenges in user's object size estimation within AR interactions.
• Further research is needed to address object size estimation issues in AR grasping literature.