Complete video eye tracking systems for fMRI

LiveTrack AV for fMRI

• Ideal for monitoring fixation at 3T
• Creates no scan artefacts from 1.5T up to 9.4T
• Is available for monocular and binocular eye tracking
• Offers real-time estimates of eye rotation, Direction of Gaze coordinates and pupil size
• Has an extremely fast setup time - cameras with an integrated IR illumination source are mounted directly on the head coil close to the eye
• Designed to work with BOLDscreen MR Safe LCD displays and rear-projection systems
• Includes TTL-compatible trigger input port for data synchronisation
• Dedicated eye tracking hardware with USB output that makes integration with your software very easy. Works with Presentation, ePrime, MATLAB, Python and your own custom software
• Streams a real-time video feed that allows you to monitor the participant during the scanning sesion
• Compatible with Windows, Mac OS X and GNU/Linux

Very fast setup with robust tracking results from close-to-the eye imaging

Keeping the camera close to the eye makes it much easier to align and focus the image. Unlike other vendor's remote camera configurations, our approach provides easy setup and fast calibration, and robust and reliable data with all participants. Simply point the LiveTrack AV camera at the eye, adjust the focus if needed and start recording.

Our MR Safe cameras have an integrated infrared 950nm illumination source. They give the best data when they are positioned behind a dielectric "cold" mirror. Cold mirrors are special optical components that are coated with a dichroic filter that reflects visible light while transmitting infrared wavelengths.

This allows the cameras to be optimally aligned in direct sight of the participant’s eyes, but at the same time hidden behind the mirror outside the participant’s view. The cameras can unobtrusively image each eye using infrared 950nm light through the mirror.

The participant sees the visible light image reflected from the cold mirror, and can therefore view a stimulus display placed outside the magnet bore. Our BOLDscreen MR Safe LCD displays are ideal for this purpose: they can be placed right at the opening of the bore, to give maximum field of view.

Shielded copper cable

The camera uses carefully shielded and filtered circuitry to isolate the video signal from the MR gradients and RF pulses.

Novel Mirror Mounts

A full range of bespoke mounts are available and are highly recommended; they include a cold mirror so that the camera can be positioned completely outside the participant's field of view. This optical design makes the setup for each participant fast and repeatable and provides the optimum optical alignment for robust tracking.

Dedicated image processing

The self-contained LiveTrack AV signal processing unit analyses the video signal and identifies the pupil and corneal reflection. The video image stream, tracked eye position and pupil size data are all returned to the host computer across a high-speed USB2 interface to the stimulus computer.

External trigger input

A separate TTL-compatible signal is recorded with the eye data for easy synchronisation with the stimulus, MR sequence, or any other external equipment.

Example Data

Watch the video below to see some example eye tracking data acquired using the LiveTrack Viewer software utility. The data is calculated by the LiveTrack AV signal processing unit at 60Hz and sent to the computer on USB.