SR Research EyeLink Portable Duo User Manual page 58

3) Please measure the screen dimensions, the shortest distance in millimeters
from the back of the camera case to the screen (for the "Camera-to-Screen
Distance" setting), and update all sections of the "Screen Settings"
configuration tool (see section 5.4 of the EyeLink Portable Duo Installation
Guide).
4) Start the Host PC application, click the "Operating Mode" panel and choose
"Remote Mode" if the eye tracker is not set to the intended mode.
5) After the subject is seated, check the camera image displayed on the Host
PC. If the participants' eyes are not displayed in the vertical center of the
camera view, adjust the camera angle by holding the camera with your left
hand and tilting it to the intended angle, and then tightening the clamping
knob on the right side of the mount to keep the camera at the intended
position. Adjust the angle of the laptop if the participants' eyes are not
displayed in the horizontal center of the camera view (see Figure 3-4).
6) Now continue with instructions in section 3.2.2.3 "Participant Setup in the
Remote Mode".
3.2.2.3 Participant Setup in the Remote Mode
Place a target sticker on the participant's forehead (see Figure 3-5). This small
target sticker allows tracking of head position even when the pupil image is lost
(i.e., during blinks or sudden movements). Ideally, it should be just above the
eyebrow of the tracked eye if tracking monocularly or on the forehead between
the two eyes if tracking binocularly. If the target sticker is placed too much
towards the side of the forehead (see bottom panel of Figure 3-5), the tracker
may report a BIG ANGLE error in the target thumbnail image when the
participant rotates the head in the direction of the sticker.
For optimal performance, adjust the participant's seating so that the tracker
reports a target-to-camera distance of about 520 mm under the zoomed target
view. The distance scale at the lower left corner of the Setup screen provides
instantaneous feedback about the current viewing distance.
48 An EyeLink Portable Duo Tutorial: Running an Experiment
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