Development of a low cost eye gaze tracker

Eye gaze tracker is a device for monitoring and recording eye motion and related eye data. It is a hands-off, not intrusive, remote human-computer interface that can be used to track a user's gazepoint. It allows an operator to interact with their environment using only their eyes. During 2 decades of development, hundreds of eyegaze, eye-controlled, computer/communication systems have been sold around the world, primarily as an assistive device for people with disabilities and as a tool for human factors research. Gaze information plays an important role in identifying a person's focus of attention. The information can provide useful communication cues to a multimodal interface. A person's gaze direction is determined by two factors: the orientation of the head, and the orientation of the eyes. While the orientation of the head determines the overall direction of the gaze, the orientation of the eyes determines the exact gaze direction and is limited by the head orientation. To be applied in general computer interfaces, an ideal eye tracker should: be precise to minutes of arc; have repetitive behaviour; work under different conditions such as lighting fluctuations, operator with glasses and contact etc; allow for free head motion; be easy to use on a variety of subjects. This paper regards the development of an economic and ergonomic eye gaze tracker using time compression techniques. A low cost and custom fit approach is used in the development of this Eye gaze tracker: a single low-cost B/W mini-camera (Table 1) is used to acquire video images. A good image contrast is obtained using one IR LED, positioned in proximity of the camera, with orientation suitable to produce the dark-pupil effect: this setup allows an easy pupil image identification. The device shape is designed on a head virtual model obtained from the digitalization of a physical pattern; the point cloud of the head physical model is acquired using a laser scanner. The functional prototypes are produced using the fused deposition modelling (ABS) and selective laser sintering techniques(aluminium/polyammide). Fifty users (students) tested the functional prototypes, complete of all components to evaluate the functional and ergonomic device characteristics. The final cost of the prototype obtained is about 10% of the cost of the product available in the market.