Designing Adaptive Transparency User Interface for Pedestrian Safety in Mobile AR

Abstract

As augmented reality (AR) glasses become integrated into daily life, their use during walking introduces critical safety challenges: virtual overlays can occlude real-world information, forcing users to divide attention between digital content and environmental hazards. While transparency control can mitigate this issue, fixed settings may be inadequate for dynamic walking contexts where lighting, scene complexity, and user motion change continuously. This paper presents an environment-aware transparency control system that dynamically adjusts AR interface opacity in real-time using a lightweight, interpretable heuristic. The system extracts visual features from the headset's passthrough camera, including scene motion, ambient brightness, and visual complexity, and combines them with head rotation velocity from inertial sensors to compute continuous transparency values. A within-subjects study (N=10) in a real-world indoor walking environment compared three interfaces: Opaque, Semi-Transparency, and Adaptive Transparency. Results show that both transparency-enabled interfaces significantly improved perceived safety and situational awareness while reducing interface interference compared to the Opaque condition (p < 0.001). Cognitive workload was reduced by 46.3–51.1% under both the Semi and Adaptive conditions. No significant differences were observed in objective walking behavior across interfaces. Although no significant differences were found between the Semi and Adaptive in either objective or subjective measures, 60% of participants preferred the Adaptive interface, suggesting that dynamic responsiveness offers perceived benefits for mobile AR safety and user experience.

Keywords: Augmented Reality, Adaptive User Interfaces, Pedestrian Safety, Transparency Control, Cognitive Workload, User Experience

DOI: 10.54941/ahfe1008143