EYE TRACKING TECHNOLOGY Presented by : RAJEESH. P

Contents Introduction What is eye tracking?.. How does it work?.. Technology Calibration Applications Eye tracking- an example Advantages Disadvantages Conclusion References

Introduction Human- computer interaction has become an increasingly important part of our daily lives . Now a days, smart phones and touch screens use fingers as input source . Eye movements are the most frequent of all human movements .

Eye movements are fundamental to the operation of the visual system Therefore the movement of user’s eyes can provide a convenient and natural source of input.

What is Eye Tracking ?.. The process of using sensors to locate features of the eyes and estimate where someone is looking .

How does it work ?..

How we look ?.. Our pupils are constantly in motion . When the pupil is moving, it’s called a ‘saccade’. During a saccade, visual perception is unlikely or even impossible .

The pupil must focus on a point in order to perceive colour, faces, writing, etc . That is called a ‘Fixation’. Fixations are linked to attention. Moving your eyes means moving attention .

The Red Eye Effect There’s a layer in our eyes that reflects infrared light . This is where the red- eye effect in photos comes from as photo flashes use infrared light . The eye tracking monitor makes use of this effect .

Technology Technology relies on infrared illumination . Most commercial eye- tracking systems available today measure point- of- regard by the “corneal- reflection/pupil- centre” method .

These kinds of trackers usually consist of a standard desktop computer with an infrared camera mounted beneath a display monitor, with image processing software to locate and identify the features of the eye used for tracking .

In operation, infrared light from an LED embedded in the infrared camera is first directed into the eye to create strong reflections in target eye .

The light enters the retina and a large proportion of it is reflected back, making the pupil appear as a bright, well defined disc (known as the “bright pupil” effect) . The corneal reflection is also generated by the infrared light, appearing as a small, but sharp,glint .

The vector between the centre of pupil and the location of the corneal reflection is measured, and, with further trigonometric calculations point- of- regard can be found .

Calibration Calibration is a key factor defining the accuracy of any eye tracker . Before using an eye tracking system , it must be calibrated for each user .

This is usually done by showing a number of calibration points on the screen and asking the user to consecutively fixate at these points, one at a time .

The relationship between the pupil position and the corneal reflections changes as a function of eye gaze direction . The images of the eye and its orientation are analyzed by the computer for each calibration point .

Each image is associated with corresponding screen coordinates . These main points are used to calculate any other point on- screen via interpolation of the data .

Applications Active : Involve device control. Eg : Gaming Eye activated login Hands-free typing

Passive : Include performance analysis of design, layout and advertising. Eg : TV commercials Street advertising Web advertising

Using Eye Tracking – an Example Two versions of an ad design were tested using eye tracking . The goal of the ad is to draw attention to the product name . Version A Version B

Eye tracking result for Version A : We see a “face effect” : The model’s face draws a lot of attention . The slogan is the other hot spot of the design. Participants will likely have read it . The product and its name get some, but not a lot of attention .

Eye tracking result for Version B : Again, we see a strong face effect. In this version, the models gaze is in line with the product and its name. The product image and name get considerably more attention. Additionally, even the product name at the bottom is noticed by a number of participants.

Advantages Eye movement is faster than other current input media . No training is required of normal users . Determine where the user’s interest is focused automatically . It is Helpful for handi-cap people when there is no option for hands and speech .

Disadvantages Can't work with the equipment (for example if they wear contact lenses or have long eye lashes). Calibrating the equipment takes time . Difficult to control eye position consciously and precisely at all times . The equipment is expensive .

Conclusion Eye tracking technology has many applications in different fields of life . It is very useful for physically disabled persons . We speculate that further developments will produce smaller, cheaper eye trackers . So, the conclusion is that it can be used and useful to everyone .

References www. theeyetribe.com/about www.newtechworld.net/senseye-a-technology-to- control-your-tablet-using-your-eye www.assistivetechnologyblog.com/2012/12/the-eye- tribe-eye-tracker-in-tablets.html

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