RemoteEye: An open-source high-speed remote eye tracker: Implementation insights of a pupil- and glint-detection algorithm for high-speed remote eye tracking

The increasing employment of eye-tracking technology in different application areas and in vision research has led to an increased need to measure fast eye-movement events. Whereas the cost of commercial high-speed eye trackers (above 300 Hz) is usually in the tens of thousands of EUR, to date, only a small number of studies have proposed low-cost solutions. Existing low-cost solutions however, focus solely on lower frame rates (up to 120 Hz) that might suffice for basic eye tracking, leaving a gap when it comes to the investigation of high-speed saccadic eye movements. In this paper, we present and evaluate a system designed to track such high-speed eye movements, achieving operating frequencies well beyond 500 Hz. This includes methods to effectively and robustly detect and track glints and pupils in the context of high-speed remote eye tracking, which, paired with a geometric eye model, achieved an average gaze estimation error below 1 degree and average precision of 0.38 degrees. Moreover, average undetection rate was only 0.33%. At a total investment of less than 600 EUR, the proposed system represents a competitive and suitable alternative to commercial systems at a tiny fraction of the cost, with the additional advantage that it can be freely tuned by investigators to fit their requirements independent of eye-tracker vendors.