Introduction to Gaze Interaction

Brief History And Background Of Modern Gaze Tracking

Early eye tracking systems were used for studying the nature of human eye movements rather than for interaction. First studies on human eye movement were made by direct observation (see Wade & Tatler, 2005, for an extensive review of the history of eye movement research). The early devices were often invasive and uncomfortable as they required the user to wear special instruments or their head position to be fixed by using, for example, a bite bar. The highly cited pioneering work by Yarbus (originally published in 1956 in Russian, reprinted in English in 1967) was conducted using a device with a ‘cap’ that was “attached by suction to the eyeball”. This ‘suction device’ required that “the cornea is anesthetized, the lids taped apart, and the subject trained to inhibit the natural tendency to move the eyes” as a precaution to prevent injury on the eye or the device (Yarbus, 1967: quotes taken from the Foreword). A number of experiments on characteristics of eye movements and visual perception were carried out using this device.

The first “non-invasive” eye tracking apparatus, based on photography and light reflected from the cornea, was developed by Dodge and Cline in the early 1900s (Wade & Tatler, 2005). This “Dodge Photochronograph” inspired many later eye tracking devices and is considered the primary ancestor of the current video-based corneal reflection eye tracking systems. The device, and later improved versions of it, were used to categorize numerous basic eye movement properties and types, and laid the foundation for modern eye movement research. Over the years, major effort has been invested into the development of eye tracking technology and more accurate gaze estimation methods (see, e.g., Young & Sheena, 1975; Duchowski, 2003; Li, Babcock, & Parkhurst, 2006; Hansen & Ji, 2010). As a result, usability of modern eye trackers has vastly improved since these early days of eye movement tracking (for examples, see Figures 1 and 2 below).

Figure 1.

Some of the earlier devices required manual adjustment of the analogue video via a separate control unit (on the left; © 1999 TAUCHI. Used with permission). Today, the digital video image can be analyzed in real time through an all-in-one system that includes a laptop, screen and video camera embedded in a single portable unit (on the right; © 2007 COGAIN. Used with permission).

Figure 2.

A gaze tracking device tracks the movements of the eye and a computer program maps the user’s gaze into co-ordinates of the screen. The information on the user’s visual attention (“point of regard”) is beneficial for both diagnostic and interactive applications.(© 2001, 2003 TAUCHI, tauchi.cs.uta.fi. Used with permission.)