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What is a blink? : Classifying and characterizing blinks in eye openness signals

Nyström, Marcus LU orcid ; Andersson, Richard LU ; Niehorster, Diederick C. LU orcid ; Hessels, Roy S. and Hooge, Ignace T. C. LU (2024) In Behavior Research Methods
Abstract

Blinks, the closing and opening of the eyelids, are used in a wide array of fields where human function and behavior are studied. In data from video-based eye trackers, blink rate and duration are often estimated from the pupil-size signal. However, blinks and their parameters can be estimated only indirectly from this signal, since it does not explicitly contain information about the eyelid position. We ask whether blinks detected from an eye openness signal that estimates the distance between the eyelids (EO blinks) are comparable to blinks detected with a traditional algorithm using the pupil-size signal (PS blinks) and how robust blink detection is when data quality is low. In terms of rate, there was an almost-perfect overlap... (More)

Blinks, the closing and opening of the eyelids, are used in a wide array of fields where human function and behavior are studied. In data from video-based eye trackers, blink rate and duration are often estimated from the pupil-size signal. However, blinks and their parameters can be estimated only indirectly from this signal, since it does not explicitly contain information about the eyelid position. We ask whether blinks detected from an eye openness signal that estimates the distance between the eyelids (EO blinks) are comparable to blinks detected with a traditional algorithm using the pupil-size signal (PS blinks) and how robust blink detection is when data quality is low. In terms of rate, there was an almost-perfect overlap between EO and PS blink (F1 score: 0.98) when the head was in the center of the eye tracker's tracking range where data quality was high and a high overlap (F1 score 0.94) when the head was at the edge of the tracking range where data quality was worse. When there was a difference in blink rate between EO and PS blinks, it was mainly due to data loss in the pupil-size signal. Blink durations were about 60 ms longer in EO blinks compared to PS blinks. Moreover, the dynamics of EO blinks was similar to results from previous literature. We conclude that the eye openness signal together with our proposed blink detection algorithm provides an advantageous method to detect and describe blinks in greater detail.

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Please use this url to cite or link to this publication:
author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Blink, Eye tracking
in
Behavior Research Methods
pages
20 pages
publisher
Springer
external identifiers
  • scopus:85186611630
  • pmid:38424292
ISSN
1554-3528
DOI
10.3758/s13428-023-02333-9
language
English
LU publication?
yes
id
4a4c43fd-5d39-4809-abcc-d5fc43022e34
date added to LUP
2024-03-02 21:44:15
date last changed
2024-04-24 14:46:04
@article{4a4c43fd-5d39-4809-abcc-d5fc43022e34,
  abstract     = {{<p>Blinks, the closing and opening of the eyelids, are used in a wide array of fields where human function and behavior are studied. In data from video-based eye trackers, blink rate and duration are often estimated from the pupil-size signal. However, blinks and their parameters can be estimated only indirectly from this signal, since it does not explicitly contain information about the eyelid position. We ask whether blinks detected from an eye openness signal that estimates the distance between the eyelids (EO blinks) are comparable to blinks detected with a traditional algorithm using the pupil-size signal (PS blinks) and how robust blink detection is when data quality is low. In terms of rate, there was an almost-perfect overlap between EO and PS blink (F1 score: 0.98) when the head was in the center of the eye tracker's tracking range where data quality was high and a high overlap (F1 score 0.94) when the head was at the edge of the tracking range where data quality was worse. When there was a difference in blink rate between EO and PS blinks, it was mainly due to data loss in the pupil-size signal. Blink durations were about 60 ms longer in EO blinks compared to PS blinks. Moreover, the dynamics of EO blinks was similar to results from previous literature. We conclude that the eye openness signal together with our proposed blink detection algorithm provides an advantageous method to detect and describe blinks in greater detail.</p>}},
  author       = {{Nyström, Marcus and Andersson, Richard and Niehorster, Diederick C. and Hessels, Roy S. and Hooge, Ignace T. C.}},
  issn         = {{1554-3528}},
  keywords     = {{Blink; Eye tracking}},
  language     = {{eng}},
  month        = {{02}},
  publisher    = {{Springer}},
  series       = {{Behavior Research Methods}},
  title        = {{What is a blink? : Classifying and characterizing blinks in eye openness signals}},
  url          = {{http://dx.doi.org/10.3758/s13428-023-02333-9}},
  doi          = {{10.3758/s13428-023-02333-9}},
  year         = {{2024}},
}