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Long Range Mount Installation
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terminal on one side of the plate it MUST connect to the red-coded connector of the cable on
the other side of the plate. Failing to match these color codes will reverse positive and negative
charges and will harm the eye tracker.
Rechargeable Battery System.
The third power solution listed above involves a rechargeable
battery pack (see rightmost image of Figure 7-7) located near the Camera Head and
Illuminator. A simple cable with pressure-release connectors on either end connects the battery
output to the Camera Head and Illuminator. See the User Manual for detailed battery use and
maintenance information.
7.7
Long Range Camera Setup
Follow these steps to set up the camera and illuminator for Long Range tracking. The intent is
that these steps should only have to be done once to use the Camera and Illuminator in a given
configuration. After initial set-up, multiple subjects can be run under identical conditions (e.g.,
tracking the right eye at a particular distance) requiring only minor focusing or positioning
from subject to subject.
This section is intended to be a general overview of the steps involved for ANY mount. As such
it is more general than may be desired for particular installations such as for MEG or MRI.
Readers interested in a more specific solution for particular MEG or MRI hardware may wish to
skip ahead to Section 7.8 for MEG or Section 7.9 for MRI mounts.
7.7.1
Acquire Preliminary Measurements
The first few steps in setting up the Long Range Camera require knowing the eye-to-camera
distance, which is measured from where the lens meets the Camera Head to the bridge of the
participant’s nose, in centimeters. This is the length of the entire optical path that light will
travel from the camera to the eye.
While measuring distances, also be sure to measure the distance from the eye to the screen top
and bottom, as well as the length and width of the projected image. This time the measurement
is in millimeters. Use these values to follow “Section 8.4 Customizing Your PHYSICAL.INI
Settings” to modify the PHYSICAL.INI file settings on your Host PC. This is important to ensure
correct reporting of information presented in terms of degrees of visual angle.
7.7.2
Assemble the Long Range Mount Components
1)
Position the Camera Head and Illuminator.
If there are no obstructions in the line of
sight from the Camera Head or Illuminator to the eye-to-be-tracked then the side of
the Mounting Bar for these items is not critically important, though having the
Illuminator on the same side as the tracked eye (Camera Head more centrally
located) may result in better illumination for monocular tracking .
Decide on the side of the Mounting Bar to place the Camera Head and Illuminator
and slip them into position, ensuring the cabling for the Camera Head is emerging
