Wearable line-of-sight detection system using micro-fabricated transparent optical sensors on eyeglasses

Line-of-sight (LOS) information acquired from the eye is quite valuable in information communication technology (ICT). LOS detection systems that do not impose physical or psychological stress are strongly demanded. In this study, we fabricated and demonstrated a wearable LOS detection system that consists of micro-fabricated transparent optical sensors affixed on eyeglasses. The sensor array detects the difference in the intensity of light reflected from the pupil and the white of the eye (sclera) and then determines the view angle. The system is also equipped with a CCD camera to acquire the user's field-of-view (FOV) to deduce the LOS by using the detected view angle. This paper first presents the shapes and arrangement of the array of four cells on the eyeglasses. With only four sensor cells, we can detect the view angle in both the horizontal and vertical directions. We describe the LOS detection system and show experimentally that the error is as small as 1.5. In addition, we deduce the characteristic output signals of the cells when the user blinks. Eye-blinking can be used as a trigger to initiate LOS measurement, select objects, etc. Finally, we successfully demonstrate the effectiveness of the proposed system to detect a user's LOS in applications that include the selection of objects to express the user's intent and tracking the point of regards to deduce the user's interest.