SmartEye: An Accurate Infrared Eye Tracking System for Smartphones

The capability to estimate where a user is looking on a screen is known as gaze estimation or eye tracking. It has been used in medical applications including assessment of mood and learning disorders, and brain injury diagnosis. If accurate eye tracking could be integrated into commodity smartphones these diagnostics could be broadly deployed at very low cost. The highest accuracy and most robust eye tracking methods employ infrared cameras and illumination which are not yet available on all standard smartphones. In this paper, we present an accurate infrared eye tracking system on a smartphone, named SmartEye, on an industrial prototype phone equipped with an infrared camera and illumination. The system is accurate in the presence of head pose variation and device movements in the user's hands, and requires only a one-time calibration routine to measure specific parameters of the user's eye. Our system achieves a gaze estimation bias of 0.57 degrees at a 20cm distance from the user, 5 times better than state-of-the art mobile device eye-tracking systems that do not use infrared illumination. Our system also allows for free head movements at distances between 20-40cm with a moderate increase in average gaze bias (to similar to 1 degrees), and can operate at 12fps. This enhanced accuracy and increased mobility can expand significantly the range of eye-tracking applications that can be supported by smartphones.