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FAQ: How do I point / focus the illuminator on the Long Range mount?
Sam
Research Support Specialist
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Joined: Aug 2020
Posts: 1,015

#1
09-09-2020, 02:06 PM
Since the long-range infrared illuminator moves independently of the camera, it is crucial to align its infrared beam with the camera's focal point. The steps below provide a general guide for this process. For a more detailed walkthrough with visual aids, please see our Long-range Mount Video Tutorials.

Please follow the steps below or watch our MRI Eye Tracker Positioning Training Video for a step-by-step guide:
  1. Use the mounting bar’s ball-and-socket joint to point the camera so that the eye being tracked is centered in the camera's image.
  2. Once the eye is centered, extend the illuminator sleeve fully (to 150 cm) and lock it into position. This focuses the illumination beam as tightly as possible, making its edges more visible and easier to adjust.
       
  3. Next, use the triangular knob on the bottom of the illuminator to adjust its horizontal position.
       
  4. Watch the camera's global view on either the Host PC monitor or the Display PC. (To switch views, press the [Enter] key on the Display PC or click [Image -> Display PC] on the Host PC. Use the left and right arrow keys to toggle between images).
  5. Turn on Threshold Coloring. Adjust the illuminator's position until the cyan color is maximized in the camera image, especially at the center where the eye is located. (Cyan indicates the Corneal Reflection, which corresponds to the brightest parts of the image).
       
  6. Use the round knob that holds the illuminator to the mounting bar to adjust its vertical position, again maximizing the cyan in the image.
       
  7. Finally, move the illuminator sleeve back to the prescribed length for the desired eye-to-camera distance and lock it in position.
Alternative Method:
You can also ask the participant to look at the illuminator and tell you when the LEDs appear brightest or sharpest (they will see a faint red glow). Please note that some participants may not be able to perceive this glow, especially when using the 940nm illuminator.