Driver attention state estimation

A system for estimating an attention state of a subject within a scene, the system comprising:

• an imaging camera configured to capture digital images of the subject;
• one or more light sources configured to illuminate the subject during a period in which the digital images are captured;
• and
• a processor circuit configured to:
• process the captured images and to generate subject attention data of the subject;
• generate a primary visual attention ray of the subject from current subject attention data;
• generate an angular distribution of visual attention rays having an origin common to the primary visual attention ray;
• project the primary visual attention ray and the angular distribution of visual attention rays onto a digital representation of the scene having a plurality of predefined regions of interest to thereby generate projected visual attention rays;
• determine intersections of the projected visual attention rays with one or more of the regions of interest;
• applying weightings to particular regions of interest;
• and
• based on the intersections, determining an estimated attention state of the subject's attention including a likely region of interest of the subject's attention;
• and
• wherein the likely region of interest of the subject's attention is determined as the region of interest having the either the most intersecting visual attention rays or the highest value based on a weighted sum of intersections of the visual attention rays with the one or more regions of interest.