Illumination-free gaze estimation method for first-person vision wearable device

Gaze estimation is a key technology to understand a person´s interests and intents, and it is becoming more popular in daily situations such as driving scenarios. Wearable gaze estimation devices are use for long periods of time, therefore non-active sources are not desirable from a safety point of view. Gaze estimation that does not rely on active source, is performed by locating iris position. To estimate the iris position accurately, most studies use ellipse fitting in which the ellipse is defined by 5 parameters(position (x,y), rotation angle, semi-major axis and semi-minor axis). We claim that, for iris position estimation, 5 parameters are redundant because they might be influenced by non-iris edges. Therefore, we propose to use 2 parameters(position) introducing a 3D eye model(the transformation between eye and camera coordinate and eyeball/iris size). Given 3D eye model, projected ellipse that represents iris shape can be specified only by position under weak-perspective approximation. We quantitatively evaluate our method on both iris position and gaze estimation. Our results show that our method outperforms other state-of-the-art´s iris estimation and is competitive to commercial product that use infrared ray with respect to both accuracy and robustness.