Compensating For A Pupil Blocked By The Eyelid; Accuracy Display - LCT Eyegaze Edge User Manual

1.4.4 Compensating for a Pupil Blocked by the Eyelid

If the user's upper eyelid covers part of his pupil, the Eyegaze Edge will compensate for the missing
piece of the pupil and continue to predict the user's gaze point accurately. There is no need to change
the position of the screen. Note: more than half of the pupil must be visible in order for the system to
determine the pupil center and track the eye.
If the lower lid is blocking the pupil the screen may not be positioned optimally, e.g. parallel to the face.
When that occurs, the lower lid may obscure the corneal reflection and the eye cannot be tracked.
Move the screen so it is parallel to the face and you see a corneal reflection, and then start calibration.
If the user is side-lying there is no need to rotate the screen sideways. (Most people prefer to look at a
horizontal screen even when their head is sideways.) The Eyegaze Edge will sort out the blocked pupil
no matter what position the user is in.
1.4.5 Skipping Calibration points
If, during calibration the icon does not move to a new location after the user has attempted to focus on
it for a reasonable amount of time, about 15 or 20 seconds, you can skip that point by pressing fn
(function) and F2 on the manual keyboard. The icon will move to its next location and calibration may
continue. Skipping 2 locations should not overly affect the accuracy, assuming the user can
successfully fix his gaze on the remaining locations. Once skipped, there will be no opportunity to re-
take the skipped point.

1.4.6 Accuracy Display

At the end of the calibration procedure, the Eyegaze Edge displays the accuracy of the calibration that
it just performed. All the calibration icons appear on the screen at once, as well as all the locations of
the user's gaze points. Red crosses represent the gaze points. There will be no red cross displayed at
a skipped point.
Data displayed on the upper left corner of the screen shows the average accuracy of the gaze point
predictions in inches or centimeters. You can freeze the screen with the data displayed by pressing the
space bar. Pressing the space bar a second time will resume operation. The average accuracy of the
horizontal and vertical components of the gaze points is also displayed. Attaining a calibration accuracy
number of .25 inches (.63 cm) or smaller in the Standard calibration will automatically bring up either
the Eyegaze Main Menu, EyeWorld, or a child's program.
If the user is doing the Simple calibration, the Eyegaze Edge will automatically bring up the Main Menu,
EyeWorld, or a child's program when the accuracy is .66 inches (1.45 cm) or smaller. During Eyegaze
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