Glasses-free determination of absolute motion

1. An electronic device, comprising:

multiple image sensors, having different fields of view and positions, configured to capture images, wherein the electronic device is configured to:

capture the images using the image sensors;

determine, based at least in part on apparent sizes of an anatomical feature in the images and a predefined or predetermined size of the anatomical feature, absolute motion of at least a portion of an individual along a direction between at least the portion of the individual and the electronic device;

estimate a distance along the direction based at least in part on at least one of the apparent sizes of the anatomical feature in at least one of the images and the predefined or predetermined size of the anatomical feature; and

compute, based at least in part on the estimated distance and angular information associated with one or more objects in the images relative to the positions, absolute motion of at least the portion of the individual in a plane that is perpendicular to the direction.

2. The electronic device of claim 1 , wherein the at least the portion of the individual comprises eyes of the individual.

3. The electronic device of claim 1 , wherein the one or more objects comprise pupils of the individual.

4. The electronic device of claim 1 , wherein the electronic device comprises second image sensors, having different second fields of view, configured to capture second images; and

wherein the capturing, determining, estimating and computing operations are repeated for the second images to determine absolution motion of a second portion of the individual.

5. The electronic device of claim 4 , wherein the second portion of the individual comprises one of: a hand of the individual or a finger of the individual.

6. The electronic device of claim 4 , wherein the electronic device is configured to infer interaction with an object by the individual based at least in part on the determined absolute motion in the direction, the determined absolute motion in the plane or both of at least the second portion of the individual.

7. The electronic device of claim 1 , wherein the anatomical feature comprises one of: an interpupillary distance, a hand of the individual, or a finger of the individual.

8. The electronic device of claim 1 , wherein the anatomical feature is associated with the individual or a group of individuals that have one or more characteristics in common with the individual.

9. The electronic device of claim 8 , wherein the anatomical feature is an average or mean interpupillary distance.

10. The electronic device of claim 1 , wherein the electronic device comprises a time-of-flight (tof) sensor configured to capture tof information; and

wherein the absolute motion along the direction and in the plane is determined based at least in part on the tof information.

11. The electronic device of claim 1 , wherein the electronic device comprises a display; and

wherein the electronic device is configured to:

generate stereoscopic images that comprise image parallax based at least in part on the determined absolute motion along the direction and in the plane and a viewing geometry that matches or corresponds to the absolute motion along the direction and in the plane; and

provide the stereoscopic images on the display.

12. The electronic device of claim 11 , wherein the determined absolute motion in the direction, the determined absolute motion in the plane or both of at least the portion of the individual corresponds to positions of eyes or pupils of the individual; and

wherein the stereoscopic images are generated based at least in part on the positions of the eyes or pupils of the individual.

13. The electronic device of claim 11 , wherein the determined absolute motion in the direction, the determined absolute motion in the plane or both of at least the portion of the individual corresponds to a focal point of the individual, and the stereoscopic images are generated based at least in part on the focal point.

14. The method of claim 13 , wherein an intensity of a given voxel in a given one of the stereoscopic images is based at least in part on a transfer function that specifies a transparency of the given voxel and the focal point, so that the stereoscopic images comprise foveated imaging.

15. The electronic device of claim 11 , wherein the image sensors capture images that comprise eyes of the individual, a hand or finger of the individual, and the display in which the stereoscopic images are displayed; and

wherein image parallax and motion parallax of the stereoscopic images within the viewing geometry is based at least in part on the images.

16. The electronic device of claim 1 , wherein the absolute motion of at least the portion of the individual along the direction and in the plane is determined without using information associated with glasses worn by the individual or a glove worn by the individual.

17. A non-transitory computer-readable storage medium for use in conjunction with an electronic device, the computer-readable storage medium storing program instructions, wherein, when executed by the electronic device, the program instructions cause the electronic device to perform one or more operations comprising:

capturing images using image sensors;

determining, based at least in part on apparent sizes of an anatomical feature in the images and a predefined or predetermined size of the anatomical feature, absolute motion of at least a portion of an individual along a direction between at least the portion of the individual and the electronic device;

estimating a distance along the direction based at least in part on at least one of the apparent sizes of the anatomical feature in at least one of the images and the predefined or predetermined size of the anatomical feature; and

computing, based at least in part on the estimated distance and angular information associated with one or more objects in the images relative to positions of the image sensors, absolute motion of at least the portion of the individual in a plane that is perpendicular to the direction.

18. The computer-readable storage medium of claim 17 , wherein the anatomical feature comprises: an interpupillary distance, a hand of the individual, or a finger of the individual.

19. A method for determining absolute motion, comprising:

by an electronic device:

capturing images using image sensors;

determining, based at least in part on apparent sizes of an anatomical feature in the images and a predefined or predetermined size of the anatomical feature, absolute motion of at least a portion of an individual along a direction between at least the portion of the individual and the electronic device;

estimating a distance along the direction based at least in part on at least one of the apparent sizes of the anatomical feature in at least one of the images and the predefined or predetermined size of the anatomical feature; and

computing, based at least in part on the estimated distance and angular information associated with one or more objects in the images relative to positions of the image sensors, absolute motion of at least the portion of the individual in a plane that is perpendicular to the direction.

20. The method of claim 19 , wherein the anatomical feature comprises: an interpupillary distance, a hand of the individual, or a finger of the individual.