Apple Inc.
PUPIL ASSESSMENT USING MODULATED ON-AXIS ILLUMINATION

Abstract:

Various implementations determine a pupil characteristic (e.g., perimeter location, pupil shape, pupil diameter, pupil center, etc.) using on-axis illumination. On-axis illumination involves producing light from a light source that is approximately on-axis with an image sensor configured to capture reflections of the light from the light source off the eye. The light from the light source may passes through the pupil into the eye and reflect off the retina to produce a bright pupil-type light pattern in data obtained by the image sensor. The light may be pulsed at a frequency so that frequency segmentation may be used to distinguish reflections through the pupil off the retina from reflections of light from other light sources. In some implementations, the image sensor is an event camera that detects events. The pupil characteristics may be assessed by assessing events that recur in a given area at the given frequency.