LibGaze: Real-time gaze-tracking of freely moving observers for wall-sized displays

We present a mobile system for tracking the gaze of an observer in real-time as they move around freely and interact with a wall-sized display. The system combines a head-mounted eye tracker with a mo- tion capture system for tracking markers attached to the eye tracker. Our open-source software library libGaze provides routines for calibrating the sys- tem and computing the viewer’s position and gaze direction in real-time. The modular architecture of our system supports simple replacement of each of the main components with alternative technology. We use the system to perform a psychophysical user-study, designed to measure how users visually explore large displays. We find that observers use head move- ments during gaze shifts, even when these are well within the range that can be com- fortably reached by eye movements alone. This suggests that free movement is important in nor- mal gaze behaviour,motivating further applications in which the tracked user is free to move