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Influence of simulated blur on kinematic of eye movements

Compartir 08/09/2016 Publicaciones Científicas

M. Salvador, J. Gautier, C.E. Garcia-Guerra, C. Otero, J. Pujol

Purpose

The goal of this study was to assess the influence of visual blur (defocus) on fixations, macrosaccades(>22º) and microsaccades(<1º). Is visual blur involved in adjusting eye movements at both large and fine scale?

Methods

  • A data base of eye movements recorded on 168 natural images at 5 different levels of blur (using a low-pass filter) on 64 subjects was used
  • All images were presented in random order of blur magnitude and participants were told to move their gaze freely across each image during 3 seconds.
  • Monocular Eye-Data were obtained with the Eye-tracker ETL 400 ISCAN (240Hz,<1º).
  • We established the amount of dioptric blur matching the Gaussian blur.
  • The properties of the macro saccades, fixations and micro saccades in blurred images were measured.

Conclusions

  • When blur increased: The number of fixations decreased. It may be that fixations tend to be longer to extract the high frequency information of the scene.
    • The number of microsaccades decreased and there were a large variety of microsaccades.
    • It appears that microsaccade production have a potential role in counteracting the increasing blur.
    • Macrosaccades amplitude(>22º)increased and all them were almost of the same size. Probably, we do more large exploratory saccades roughly of the same size in order to identify the gist of the scene.
  • Ocular movements in this context of free-viewing could help to discriminate, objectively, the observer’s perception of blur.
influence_-of-stimulated-blur-on-kinematic-of-eye-movements-salvador.pdf

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