Lecture 8: Eye Tracking II

Question 1

What is the Dwell-time Method?

Answer 1

With the dwell-time method the gaze has to stay (dwell) on an interaction object for a certain time, the dwell time, to trigger an action.

Typical dwell times are in the range from 300 ms to 1000 ms

A charging-discharging mechanism mitigates problems with outliers

Question 2

Name text entry systems/methods with gaze

Answer 2

Eye Typing

Dwell-time

EyeSwipe

Dasher (text entry system which works with mouse input, but also with gaze)

Smooth Pursuit-based Text Entry

Question 3

What was the Vision from 1981 - Bolt

Answer 3

Gaze-Orchestrated dynamic windows

The intent of the reported research is to introduce order and control, through the creation of a dynamic, gaze-interactive interface.

Question 4

Works Fitts’ Law for the eyes?

Answer 4

No, Fitts’ Law does not apply to saccadic eye movements. During a saccade the eye moves so quick that it is blind.

Question 5

Name a formula for measuring times for Eye Pointing

Answer 5

Question 6

What is the Midas Touch problem in gaze interaction and who identified it?

Answer 6

Jacob:

We accidentally trigger actions with our gaze. It refers to the difficulty of performing fine motor tasks

Question 7

What is the concept of Gaze Gestures and what is its advantage?

Answer 7

The idea is to detect a series of strokes.

The big advantage of this concept is that no calibration is necessary as it detects only relative movements.

Question 8

Which gaze interaction technique would work with public displays and why?

Answer 8

Gaze gestures

Do not need calibration
Work on longer distances because accuracy is not critical

But it is slower than using the dwell time

Question 9

What can we do to avoid gaze gestures by chance?

Answer 9

Use a gesture with many strokes
Use a big grid size
Implement a timeout

Question 10

What is smooth persuits? And how is its application?

Answer 10

Smooth pursuits in gaze interaction refer to the continuous tracking of a moving object with the eyes. We can measure if the movement of the eyes cerellate with the movement of the object.

Application:

• Selection of targets
• Continuous input (increase/decrese
• Calibration (data for callibration)

Do not need calibration

Question 11

What are recommendations for smooth persuits?

Answer 11

Never ending movement is preferabl

Use closed trajectory, such as a circle

Target movement should be predictable

Question 12

What are challenges of Eye Tracking?

Answer 12

• Midas Touch
• Low accuracy
• Calibration issue
• Privacy issues

Question 13

What is the better target hit condition for small targets?

Answer 13

If (Pointeye - PointObject < accuracy)