THE ROLE OF LATEST FIXATIONS ON ONGOING VISUAL SEARCH

A MODEL TO EVALUATE THE SELECTION MECHANISM

Giacomo Veneri, Pamela Federighi,Francesca Rosini, Elena Pretegiani, Antonio Federico, Alessandra Rufa

Eye tracking & Vision Applications Lab (EVA Lab) Department of Neurological Neurosurgical and Behavioral Science

University of Siena, Italy

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Outline

• Top-Down vs Bottom-Up on ongoing visual search

• Efficiency on Visual search• (Bayesian) Model on visual search

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Task

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“Visual Search depends on sensory, perceptual and cognitive processes” [colby 2009]

Il TMT misuar la capcità di esplorare ed eseguire una sequenza in modo corretto

TMTB è un mappa TMTB è un mappa viariante in cui i target viariante in cui i target diventano distrattoridiventano distrattori

[Wolwer 2003]

Mathematical Method

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Fixations

Direction vs Previous fixations

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In order to test an overall validity of the model, we calculated for each test the DEMINFIX(T) – DEMINFIX and the DEMAXFIX(T) – DEMAXFIX.Figures

show that saccade direction take in consideration mainly fixations of last 1000ms (1s).

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Model

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Human vs Machine

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Conclusion

• We found significant differences among tasks and a correlation between the efficiency (time elapsed) to explore the task and the ability to inhibit the BAF.

• The command constraint (goal-driven) which is modulated by the image salience versus BAF.

• The selection mechanism that drives this competition. Further works will be directed to evaluate the relation between the BAF and the inhibition of return.

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