Direct Measurement of the System Latency of Gaze-contingent Displays
Overview
Authors
Affiliations
Gaze-contingent displays combine a display device with an eyetracking system to rapidly update an image on the basis of the measured eye position. All such systems have a delay, the system latency, between a change in gaze location and the related change in the display. The system latency is the result of the delays contributed by the eyetracker, the display computer, and the display, and it is affected by the properties of each component, which may include variability. We present a direct, simple, and low-cost method to measure the system latency. The technique uses a device to briefly blind the eyetracker system (e.g., for video-based eyetrackers, a device with infrared light-emitting diodes (LED)), creating an eyetracker event that triggers a change to the display monitor. The time between these two events, as captured by a relatively low-cost consumer camera with high-speed video capability (1,000 Hz), is an accurate measurement of the system latency. With multiple measurements, the distribution of system latencies can be characterized. The same approach can be used to synchronize the eye position time series and a video recording of the visual stimuli that would be displayed in a particular gaze-contingent experiment. We present system latency assessments for several popular types of displays and discuss what values are acceptable for different applications, as well as how system latencies might be improved.
The fundamentals of eye tracking part 4: Tools for conducting an eye tracking study.
Niehorster D, Nystrom M, Hessels R, Andersson R, Benjamins J, Hansen D Behav Res Methods. 2025; 57(1):46.
PMID: 39762687 PMC: 11703944. DOI: 10.3758/s13428-024-02529-7.
Biebl B, Arcidiacono E, Kacianka S, Rieger J, Bengler K Front Neuroergon. 2024; 3:916169.
PMID: 38235462 PMC: 10790882. DOI: 10.3389/fnrgo.2022.916169.
Assessing the data quality of AdHawk MindLink eye-tracking glasses.
Huang Z, Duan X, Zhu G, Zhang S, Wang R, Wang Z Behav Res Methods. 2024; 56(6):5771-5787.
PMID: 38168041 DOI: 10.3758/s13428-023-02310-2.
Eisma Y, Bakay A, de Winter J Hum Factors. 2023; 66(6):1770-1785.
PMID: 37210670 PMC: 11044528. DOI: 10.1177/00187208231176148.
Biles M, Maniglia M, Yadav I, Vice J, Visscher K Invest Ophthalmol Vis Sci. 2023; 64(1):14.
PMID: 36656567 PMC: 9872837. DOI: 10.1167/iovs.64.1.14.