Characterizing gaze position signals and synthesizing noise during fixations in eye-tracking data.

Content Provider	Europe PMC
Author	Niehorster, Diederick C. Zemblys, Raimondas Beelders, Tanya Holmqvist, Kenneth
Abstract	The magnitude of variation in the gaze position signals recorded by an eye tracker, also known as its precision, is an important aspect of an eye tracker’s data quality. However, data quality of eye-tracking signals is still poorly understood. In this paper, we therefore investigate the following: (1) How do the various available measures characterizing eye-tracking data during fixation relate to each other? (2) How are they influenced by signal type? (3) What type of noise should be used to augment eye-tracking data when evaluating eye-movement analysis methods? To support our analysis, this paper presents new measures to characterize signal type and signal magnitude based on RMS-S2S and STD, two established measures of precision. Simulations are performed to investigate how each of these measures depends on the number of gaze position samples over which they are calculated, and to reveal how RMS-S2S and STD relate to each other and to measures characterizing the temporal spectrum composition of the recorded gaze position signal. Further empirical investigations were performed using gaze position data recorded with five eye trackers from human and artificial eyes. We found that although the examined eye trackers produce gaze position signals with different characteristics, the relations between precision measures derived from simulations are borne out by the data. We furthermore conclude that data with a range of signal type values should be used to assess the robustness of eye-movement analysis methods. We present a method for generating artificial eye-tracker noise of any signal type and magnitude.
Related Links	https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC7725698&blobtype=pdf
ISSN	1554351X
Journal	Behavior Research Methods [Behav Res Methods]
Volume Number	52
DOI	10.3758/s13428-020-01400-9
PubMed Central reference number	PMC7725698
Issue Number	6
PubMed reference number	32472501
e-ISSN	15543528
Language	English
Publisher	Springer US
Publisher Date	2020-12-01
Publisher Place	New York
Access Restriction	Open
Rights License	Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. © The Author(s) 2020
Subject Keyword	Eye tracking Precision Data quality Fixational eye movements Power spectrum Signal color
Content Type	Text
Resource Type	Article
Subject	Experimental and Cognitive Psychology Arts and Humanities Developmental and Educational Psychology Psychology