Eye Tracking: Viewing the World Through Someone Else’s Eyes
The best way to describe a new approach to eye tracking being developed at New York City’s Columbia is a method that “looks at the world from someone else’s eyes.” A computer scientist, Shree Nayar, and his colleague, Ko Nashino, have developed a way to not only recreate the image of a person’s surroundings as it is reflected on the surface of their eyeball, but also use this image to identify where the person is actually looking.
Eyes have a round, glossy surface that reflects light much like the way the surface of a body of water does. Similar to a mirror, the surface of the eyeball reflects an image of the surrounding environment. Nayar’s method uses a high-resolution video or snapshot image of the eye captured with a simple point-and-shoot camera. First, the computer program recognizes the corneal region of the eye by detecting the edge of where the iris (the colored part of your eye) and the sclera (the white area) meet. The direction of the eye’s gaze is then determined by a computer program that analyzes the shape of the elliptical curve of the cornea. Using this information, “a circular, fishbowl-like image” (called an environmental map) is created of the surroundings being reflected on the eye’s surface. This environmental map, in combination with the details on its tilt toward the camera and the directional orientation of the person’s gaze, can be analyzed with Nayar’s computer program, pinpointing within 5 to ten degrees where the person is looking.
This new method eliminates some of the limitations of existing eye tracking technologies. Whereas current eye tracking devices are either wearable headsets or large monitors and tend to be intrusive or depended on complete stillness of the head, this technique only requires a high resolution picture of the subject’s eye. Nayar has high hopes for future applications of this eye tracking technique in the areas of assistive technology, the psychology field, the advertising industry and human-computer interaction. Another unique use of this process is to examine the reflections in the eyes of old photographs to find out more about the settings in which they were taken. There are many different approaches to eye tracking being developed throughout the industry bringing it closer and closer to becoming a mainstream technology.