Method and system for determining a current gaze direction

System for determining a gaze point of a second user in relation to an entity using a digital camera, the system comprising a calibration module, arranged to determine calibration information in relation to the digital camera by

• receiving from the digital camera at least one calibration image, being a depiction of at least one eye of a first user, wherein the first user may be the same as or different from the second user;
• performing digital image processing on the calibration image to locate and deter-mine an in-image feature size dimension of a feature of the entity as reflected in said eye of the first user;
• and to locate a limbus of said eye of the first user and determine an in-image limbus size dimension of said limbus;
• determining a current distance between the eye of the first user and the entity based on said in-image feature size dimension, said in-image limbus size dimension, a curvature of the cornea of the eye of the first user, a physical limbus size dimension of the eye of the first user and a physical size of the feature;
• and
• determine said calibration information in the form of a focal length and/or a field of view of the digital camera based on said current distance and said physical limbus size dimension,
• the system further comprising a gaze point detection module, arranged to detect a current gaze point of a second user, the second user being the first user or a different user, by
• receiving from the digital camera a digital tracking image, depicting at least one eye of the second user;
• performing digital image processing on the tracking image to locate and deter-mine a facial measure, of a facial feature of the second user, the facial feature being visible in said tracking image;
• and
• detecting said current gaze point of the second user based on a detected gaze di-rection of the second user, said facial measure, said calibration information and a spatial interrelationship between the digital camera and the entity.