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

Niehorster, Diederick C. LU orcid ; Zemblys, Raimondas ; Beelders, Tanya and Holmqvist, Kenneth LU (2020) In Behavior Research Methods 52(6). p.2515-2534
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.... (More)

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.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Data quality, Eye tracking, Fixational eye movements, Power spectrum, Precision, Signal color
in
Behavior Research Methods
volume
52
issue
6
pages
20 pages
publisher
Springer
external identifiers
  • scopus:85085602185
  • pmid:32472501
ISSN
1554-351X
DOI
10.3758/s13428-020-01400-9
language
English
LU publication?
yes
id
ce52880c-3824-4f2a-a6d0-17e11b670f11
date added to LUP
2020-06-06 22:41:24
date last changed
2024-06-13 17:13:06
@article{ce52880c-3824-4f2a-a6d0-17e11b670f11,
  abstract     = {{<p>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.</p>}},
  author       = {{Niehorster, Diederick C. and Zemblys, Raimondas and Beelders, Tanya and Holmqvist, Kenneth}},
  issn         = {{1554-351X}},
  keywords     = {{Data quality; Eye tracking; Fixational eye movements; Power spectrum; Precision; Signal color}},
  language     = {{eng}},
  number       = {{6}},
  pages        = {{2515--2534}},
  publisher    = {{Springer}},
  series       = {{Behavior Research Methods}},
  title        = {{Characterizing gaze position signals and synthesizing noise during fixations in eye-tracking data}},
  url          = {{http://dx.doi.org/10.3758/s13428-020-01400-9}},
  doi          = {{10.3758/s13428-020-01400-9}},
  volume       = {{52}},
  year         = {{2020}},
}