Shepherd Center evaluates vision-based communication and control system for patients who cannot speak

ATLANTA (September 8, 2009) – Shepherd Center’s Assistive Technology Center has begun using a vision-based communication and control technology called Eyegaze Edge.

The technology, which was developed by LC Technologies Inc., allows users to perform a broad variety of functions including: speech generation, environmental control (lights and appliances), typing, and running both mouse- and keyboard-controlled applications on the company’s Edge screen. Also, the Edge can serve as a keyboard and mouse interface for a user’s own computer.

“This technology has the potential to transform the lives of quadriplegics whose high-level injuries make it difficult for them to speak and communicate,” says John Anschutz, director of the Assistive Technology Center at Shepherd Center.

Users make selections by looking at boxes or “keys” displayed on the Edge screen. The system uses a pupil-center/corneal-reflection method to determine where a user is looking on the screen. An infrared-sensitive video camera, mounted beneath the system’s screen, takes 60 pictures per second of the user’s eye. A low-power, infrared light emitting diode (LED), mounted in the center of the camera’s lens, illuminates the eye. The LED reflects a small bit of light off the surface of the eye’s cornea. The light also shines through the pupil and reflects off the retina, the back surface of the eye, and causes the pupil to appear white. The bright-pupil effect enhances the camera’s image of the pupil so the system’s image-processing functions can locate the center of the pupil. The Edge calculates the person’s gazepoint (i.e., the coordinates of where he is looking on the screen) based on the relative positions of the pupil center and corneal reflection within the video image of the eye.