basic research on eye tracking

8/2/2019 Basic Research on Eye Tracking

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Eye Tracking Research

Daniela ZambarbieriUniversity of Pavia

“Innovative Solutions for Behavioral Research” - Milano, April 7 th , 2009

Eye Tracking Research• Basic Research

Understanding the oculomotorcontrol system

• Applied ResearchEye movement analysis as a tool forstudying human behavior



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Basic Research• Saccades• Smooth Pursuit• Eye-Head Coordination• Vestibular Nystagmus• Visuo-Vestibular Interaction

• Eye movements induced by auditorystimulation• Learning and prediction

Applied research

Eye Tracking Analysis in the Evaluationof e-learning Systems



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Applied research

• Web Usability & HCI• Market research• Measuring the visual span in a P-300

based BCI

• Sport• Emotions



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Fitts P.M., Jones R.E., Milton J.L.Eye movements of pilots during instruments landingapproachAeronautical Engineering Review, 9, 1-7, 1950

White C.T., Ford A.Eye movements during simulated radar searchJournal of the Optical Society of America, 50, 909-913, 1960

Llewellyn T., Lansdown D.M.R.Visual search patterns of radiologists in trainingRadiology, 81, 288-292, 1963



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A.L. Yarbus: “Eye Movements and Vision”, Plenum Press 1967



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Seven records of eyemovements by the samesubject. Each record lasted 3minutes.1) Free examination. Beforesubsequent recordings, thesubject was asked to:2) estimate the materialcircumstances of the family;3) give the ages of the people;4) surmise what the family hadbeen doing before the arrival ofthe "unexpected visitor;"5) remember the clothes wornby the people;6) remember the position of thepeople and objects in the room;7) estimate how long the"unexpected visitor" had beenaway from the family



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Recording eye movements

• Electrooculography

• Infrared Reflection

• Search Coil• Videooculography

A recording device should be ….

• Comfortable for the subject• Not affected by the amount of light

(indoor vs. outdoor)• Compatible with eyeglasses, sunglasses,

contact lenses• Friendly for the experimenter

– Quick and easy set up and calibration



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Other requirements• Viewing angle

• Measurement range

• Sampling rate

• Head movement

Electrooculography• Non invasive• Any kind of head, and body, movement allowed• Wide range of H & V measurement

• Eye closed• Analog signal: no limits of sampling rate• No problems due to

– Glasses and contact lenses– Environment light



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Videooculography

• Head fixed system

• Remote system

• Head mounted system



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Head fixed system

Head fixed system• Within lab experiments

– The head of the subject is fixed to therecording apparatus

– Controlled environment light– Controlled experimental material– Automatic data analysis– High sampling rate



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Remote system

Remote system• HCI and any study that makes use of

the computer display

– Controlled environment light– Controlled experimental material– Automatic data analysis– How much tolerance to head movement?– Low sampling rate



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Head mounted system

Head mounted system



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Head mounted system• Real world studies and behavioral

research– Different levels of subject’s comfort– Eyeglasses and contact lenses?– Influence of the environment light?– Manual tracking of the recorded video– Low sampling rate

Data analysis• The first step for quantitative data

analysis is the identification offixations and saccades

– Velocity-based saccade detectionalgorithms

– Dispersion- and duration-based fixation detection algorithms

– How many different algorithms exist?



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Analysis SW• Easy to use• Flexible in order to adapt to the need

of the experiment• Raw data must be always available• Let the user know exactly which

algorithm is implemented and what isthe influence of analysis settings

Heatmaps

they are appealing

but ….

handle with care !!



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Video files analysis• Head mounted devices for behavioral studies

video

• Need to be coded on a frame-by-frame basis• The analysis SW should allow the storage of

the frame code for subsequent quantitativeanalysis

Data mining• Data from eye movements can provide a lot of

information, consistent or not, depending onthe expertise and the knowledge backgroundof the user

• Fully automatic systems that provide maps,histograms, pie charts and any otherattractive visual representation could be verydangerous for the reliability of eye trackingresearch if the underlying analysis algorithmare not “certified”



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Last but not least• A further technical aspect is important

for behavioral studies in case othersignals need to be recorded:

synchronization

Lund Eye Tracking Academy• Two courses in 2008• Three courses in 2009

• Waiting for the publication of KennethHolmqvist's book about eye-trackingtheory and methods.



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European Conferences onEye Movements (ECEM)

• ECEM 1 1981 Bern, Switzerland• ECEM 2 1983 Nottingham, United Kingdom• ECEM 3 1985 Dourdan (Paris), France• ECEM 4 1987 Göttingen, Germany• ECEM 5 1989 Pavia, Italy• ECEM 6 1991 Leuven, Belgium• ECEM 7 1993 Durham, UK• ECEM 8 1995 Derby, UK• ECEM 9 1997 Ulm, Germany• ECEM 10 1999 Utrecht University, the Netherlands

• ECEM 11 2001 Turku, Finland• ECEM 12 2003 Dundee, Scotland• ECEM 13 2005 Bern, Switzerland• ECEM 14 2007 Potsdam, Germany

Next conference23 - 27 August 2009University of Southampton, UK

http://www.ecem2009.org/

Rudolf Groner is planning for ECEM2009 a symposium on

"Combining eye tracking with other data sources in usabilityresearch"



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Eye movements

in Italy ?

Gruppo Italiano per lo studio deiMovimenti Oculari (GIMO)

• GIMO è nato nel 1987 allo scopo di favorire l’incontrotra i ricercatori appartenenti a diverse discipline che,in ambito nazionale, si occupano di motilità oculare.

• GIMO ha organizzato periodicamente incontri

nazionali, e corsi di aggiornamento che sono statiraccolti in una collana pubblicata da Patron Editore.

• I movimenti saccadici• I movimenti di inseguimento lento• Le interazioni visuo-vestibolari

a cura di SebastianoTraccis e Daniela Zambarbieri



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Daniela Zambarbieri - Movimenti OculariPatron Editore, 2006



• Clear description of technicalspecifications

• Adoption of a common language

• Super partes scientific committee for

quality assessment

• Definition of standards

E E ye ye T T racking racking the world the world

Laboratory of Eye Movement and Eye-Head Coordination

University of Pavia

http://eye-head.unipv.it [email protected]

basic research on eye tracking

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