3D gaze tracker
An embodiment of the invention provides a gaze tracker for determining a gaze vector for a person, which comprises a 3D camera that and a picture camera that image the person and a controller that processes images acquired by the cameras to determine a gaze direction and origin for the gaze vector.
1. A gaze tracker for determining a gaze vector having a direction and origin for a person, the gaze tracker comprising:
a 3D camera that acquires a range image of a person located in a field of view (FOV) of the camera;
a picture camera that acquires a picture of the person in the FOV of the 3D camera; and
a controller that processes the range image and the picture to determine spatial coordinates for features of the person's head and an eye of the person, and determines a gaze direction and origin for a gaze vector of the eye.
2. A gaze tracker according to claim 1 , wherein the FOV extends to a distance from the gaze tracker equal to or greater than about 1 m.
3. A gaze tracker according to claim 1 , wherein the FOV extends to a distance from the gaze tracker equal to or greater than about 2 m.
4. A gaze tracker according to claim 1 , wherein the FOV extends to a distance from the gaze tracker equal to or greater than about 3 m.
5. A gaze tracker according to claim 1 , wherein the FOV extends from a distance from the gaze tracker equal to about 0.3 m.
6. A gaze tracker according to claim 1 and comprising a light source that illuminates at least a portion of the FOV.
7. A gaze tracker according to claim 6 wherein the controller adjusts intensity of light provided by the light source responsive to a spatial coordinate determined by the controller.
8. A gaze tracker according to claim 6 wherein the controller adjusts direction of light provided by the light source responsive to a spatial coordinate determined by the controller.
9. A gaze tracker according to claim 1 , wherein the features comprise at least one feature of the person's eye for which spatial coordinates can be used to determine gaze direction of the eye.
10. A gaze tracker according to claim 9 , wherein the at least one feature of the eye comprises at least one of the pupil, iris, sclera, and a Purkinje reflection.
11. A gaze tracker according to claim 1 , wherein the features comprise at least one feature of the person's head for which spatial coordinates can be used to determine orientation of the head.
12. A gaze tracker according to claim 11 , wherein the at least one feature of the head comprises the forehead, an eye, the nose, lips chin, and an ear.
13. A gaze tracker according to claim 1 , wherein the 3D camera comprises a stereoscopic camera.
14. A gaze tracker according to claim 1 , wherein the 3D camera comprises a time of flight (TOF) 3D camera.
15. A gaze tracker according to claim 14 , wherein the TOF 3D camera and the picture camera comprise different photosensors comprising pixels on which they image light to respectively acquire the range image and picture.
16. A gaze tracker according to claim 15 , wherein pixels in the different photosensors have different sizes.
17. A gaze tracker according to claim 16 , wherein pixels in the photosensor on which the 3D camera images light are larger than pixels in the photosensor on which the picture camera images light.
18. A gaze tracker according to claim 15 and comprising optics for adjusting magnification of imaging on the photosensors independently of each other.
19. A gaze tracker according to claim 18 wherein the controller adjusts magnification responsive to a spatial coordinate determined by the controller.
20. A method of determining a gaze direction of a person, the method comprising:
acquiring a range image of a person that provides distances to the person's features;
acquiring a contrast image of the person; and
processing the range image and the contrast image to provide a gaze vector for the person that defines a direction along which the person is looking.