US Patent 9811157 Method for gaze tracking

A method for gaze tracking achieves high performances at the same time requiring both limited processor engagement and reduced power, so as to be particularly but not exclusively fit for mobile uses is described. The method includes the steps of: obtaining a digital video stream of a face through a camera, wherein eyes or pupils are identified in corresponding boxes in the spatial domain, the size thereof being function of the face position and orientation relative to said camera, the content of the boxes being the input for the further calculations; transferring the content of the boxes to the frequency domain; applying to the boxes transferred to the frequency domain one or more sparse zones, covering together a fraction of the boxed area transferred to the frequency domain, and a filtering kernel, at least partially overlapping the sparse zones; performing a multiplication between the frequency data within each sparse zone and the kernel, combining the results in a single value for each sparse zone; and repeating the above steps obtaining for each frame said single value, fluctuation of the single value being representative of gaze direction changes along time.