Investigating the Impact of Illumination Change on the Accuracy of Head-Mounted Eye Trackers: A Protocol and Initial Results
Mohammadhossein Salari, Roman Bednarik · 2024
The advancement of eye tracking technology, including improved portability, usability, and affordability, has facilitated the transition of eye trackers from controlled laboratory settings to diverse real-world environments. One significant challenge in these real-world settings is the wide variation in illumination levels, potentially affecting eye tracking accuracy. Despite anecdotal evidence suggesting the sensitivity of head-mounted eye trackers to environmental light conditions, systematic research on this topic has been limited. This study introduces a standardized protocol for investigating the influence of lighting conditions on the accuracy of head-mounted eye trackers. We examined the performance of SMI Eye Tracking Glasses 2 Wireless under three distinct illumination levels: Low (Dark), Moderate (Normal), and High (Bright). Our experiment involved 9 participants performing accuracy tests under each lighting condition. We measured gaze accuracy while varying the illumination level during both the calibration and data recording phases. Results indicate that eye tracking accuracy is affected by the illumination level used during data collection. Best accuracy was achieved when data recording was performed under the same illumination level as the calibration. Notably, calibration under moderate illumination led to the most consistent performance across all lighting conditions. These findings provide valuable insights for researchers and practitioners using head-mounted eye trackers in varying lighting environments. The standardized protocol presented can be applied to evaluate other eye tracking systems, contributing to developing more robust mobile eye tracking techniques. Future research should investigate the generalizability of these results across different eye tracking technologies and explore potential software solutions to mitigate illumination-related accuracy issues.