Input Method and System Based on Ambient Glints

A method may involve analyzing eye-image data to determine observed movement of a reflected image over a predetermined period, using head-movement data to determine a first eye-movement component corresponding to head movement during the predetermined period, determining a first expected movement of the reflected image corresponding to the first eye-movement component, determining a second eye-movement component based on a difference between the observed movement and the first expected movement, determining a second expected movement of the reflected image based on the combination of the first eye-movement component and the second eye-movement component, determining a difference between the observed movement and the second expected movement, if the difference is less than a threshold, setting eye-movement data for the predetermined period based on the second eye-movement component; and if the difference is greater than the threshold, adjusting the first eye-movement component and repeating the method with the adjusted first eye-movement component.