Parsing visual stimuli into temporal units through eye movements

Carlo Robino, Sofia Crespi, Ottavia Silva, Claudio De'Sperati

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Automatic segmentation of a video stream poses a serious challenge to multimedia research. Here we explore the idea that temporal segmentation might include the observers' watching style. We propose a way to parse a visual stimulus into temporally-defined units by exploiting the difference of exploratory eye movements between novice and expert observers. The difference was condensed into a single quantity, the quasi-instantaneous spatial extension of the regions fixated significantly longer by either group of observers, which we termed Visual Differential Attractor (VDA). As test-bed, we presented a videotaped billiard match to novice and professional players, and recorded their eye movements. We assessed whether VDA, in tracing over time the oculomotor difference between experts and novices, would mark the individual shots embedded in the movie. Indeed, VDA showed systematic modulations over time, with peaks and toughs occurring before and after the shots, respectively. The effect disappeared by analyzing separately the scanpath of novices and experts. This finding suggests that it is possible to parse a visual stimulus into behaviorally relevant temporal units by comparing the gaze of expert and naïf observers.

Original languageEnglish
Title of host publicationEye Tracking Research and Applications Symposium (ETRA)
Number of pages4
Publication statusPublished - 2012
Event7th Eye Tracking Research and Applications Symposium, ETRA 2012 - Santa Barbara, CA, United States
Duration: Mar 28 2012Mar 30 2012


Other7th Eye Tracking Research and Applications Symposium, ETRA 2012
Country/TerritoryUnited States
CitySanta Barbara, CA


  • billiards
  • expertise
  • eye movements
  • fixations
  • indexing
  • method
  • motion
  • movies
  • parsing
  • time
  • video

ASJC Scopus subject areas

  • Computer Vision and Pattern Recognition
  • Human-Computer Interaction
  • Ophthalmology
  • Sensory Systems


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