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- 1. Eye Movement-Based Human Computer InteractionTechniques Presented by Abhilash Aravindakshan Roll no:5
- 2. Contents • Introduction • CurrentTechniques • Eye Tracking system • Methods of Measuring • Applications • Advantages • Limitation • Conclu
- 3. Introduction • Eye movement-basedinteraction is one of several areas of current research in human computer interaction in which a new interface style seems to be emerging. In the non- command style, the computer passively monitors the user and responds as appropriate, rather than waiting for the user to issue specific commands.
- 4. Current Interfacing Techniques •Normal Interface • Touch Screen • Voice • Wave • Eye movement
- 5. The Eye • Corneais a transparent structure that covers the iris pupil; a part of the focusing an eye. • Pupil is the adjustable opening at the center of the iris that varying amounts of light to eye. • Lens helps to focus light on retina. • Retina includes rods (94%), are sensitive to light and cones that capture colors. Cones are concentrated in the centre of retina - the fovea
- 6. Vision Field • Visionfield is divided in to three regions • Fovea provides the sharpest vision • Parafovea previews foveal information • Peripheral vision reacts to flashing objects and sudden movements
- 7. Types of EyeMovements • Fixation • Saccade • Pursuit • Tremor • Rotation • Drift
- 8. Methods for MeasuringEye Movements • Electronic • Mechanical • Optical/Video 1. Single point 2. Two point
- 9. Electronic Method • Themost used method is to place skin electrodes around the eyes and measure the potential differences in eye • Wide range -- poor accuracy • Better for relative than absolute eye movements • Mainly used in neurological diagnosis
- 10. Mechanical Method 1. Basedon contact lenses with • mirror planes + reflecting IR-light • coil + magnetic field 2. Very accurate 3. Very uncomfortable for users who are not used to wear lenses • Usable only for lab studies
- 11. Optical/Video based Method-single point 1.Tracking one visible feature of the eyeball, e.g.: • limbus (bondary of sclera and iris) • pupil 2. A video camera observes one of the user's eyes • Image processing software analyzes the video image and traces the tracked feature 3. Based on calibration, the system determines where the user is currently looking 4. Head movements not allowed • Bite bar or head rest is needed
- 12. Optical/Video based Method-two point 1.The same idea as in the single point method except now two features of eye are tracked – typically • corneal reflection • pupil 2. Uses IR light (invisible to human eye) to • produce corneal reflection • cause bright or dark pupil, which helps the system to recognize pupil from video image Bright pupil Corneal reflection
- 13. Eye Tracking System Cornealreflection plus pupil eye tracker
- 14. Cont... • Corneal reflectionplus pupil eye tracker • The pupil camera and illuminator operate along the same optical axis • Servo controlled mirror is used to compensate for the user’s head motions. • tracks the corneal reflection from an infrared light shining on eye and the outline of the pupil illuminated by same light. • Computes the visual line of eye gaze by relationship between two tracked points
- 15. Applications • Automated drugscreening. • Retail advertising effectiveness. • SurgicalTraining • Training and simulation • Vision Research
- 16. Advantages • Eye movementis faster than other current input media. • No training or particular coordination is required of normal users. • Can determine where the user’s interest is focused automatically. • Helpful for usability studies to understand users interact with their environments
- 17. Limitations • Equipment isexpensive • Some users can't work with the equipment (if they wear contact lenses or have long eye lashes) • Moving one's eyes is often an almost subconscious act.
- 18. Conclusion • Emerging InteractionTechnique •Eye tracking is far from “perfect” • show the intensity of the user’s attention
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