Range measurement using multiple coded apertures

1. A method comprising:

providing an image capture device having an image sensor, at least two coded apertures having different spatial frequency responses, and a lens;

storing in a memory a set of blur parameters derived from range calibration data for each coded aperture;

capturing images of the scene having a plurality of objects using each of the coded apertures; and

providing a set of deblurred images using the captured images from each coded aperture and each of the blur parameters from the stored set.

2. The method of claim 1 , wherein providing a set of deblurred images includes for each deblurred image,

initializing a candidate deblurred image;

determining a plurality of differential images representing differences between neighboring pixels in the candidate deblurred image, including a range of at least 1 or more pixels in size and including vertical, horizontal and diagonal directions;

determining a combined differential image by combining the differential images;

updating the candidate deblurred image responsive to the captured image, the blur kernel, the candidate deblurred image and the combined differential image.

3. The method of claim 1 , wherein capturing images of the scene includes capturing first and second image sequences, corresponding to the first and second coded apertures, respectively.

4. The method of claim 3 , further comprising determining range information for each image in the sequence.

5. The method of claim 4 , wherein the range information is used to identify stationary and moving objects in the scene.

6. The method of claim 5 , wherein the range information is used by the image capture device to track moving objects.

7. The method of claim 2 , wherein initializing a candidate deblurred image includes determining a difference image between the current and previous image in the image sequence; and initializing a candidate deblurred image responsive to the difference image.

8. The method of claim 7 , further comprising determining range information for the objects in the scene, responsive to the difference image.

9. The method of claim 1 , wherein providing a set of deblurred images includes using a subset of blur parameters from the stored set.

10. The method of claim 1 , wherein storing in a memory a set of blur parameters includes using a set of blur parameters derived from calibration data at a set of range values, such that there is a set of blur parameters for each coded aperture at each corresponding range value.

11. The method of claim 1 , wherein storing in a memory a set of blur parameters includes using a set of blur parameters derived from calibration data at a set of range values, such that there is not a set of blur parameters for each coded aperture for at least one range value.

12. The method of claim 1 , further comprising combining the deblurred images according to a spatial-frequency dependent weighting criterion.

13. The method of claim 1 , further comprising combining deblurred images resulting from blur parameters corresponding to each coded aperture within selected range intervals.

14. The method of claim 13 , further including combining the deblurred images according to a spatial-frequency dependent weighting criterion.

15. A digital camera system comprising:

an image sensor configured to capture one or more images of a scene;

a lens configured to image the scene onto the image sensor;

at least two coded apertures having different spatial frequency responses;

a processor-accessible memory configured to store a set of blur parameters derived from range calibration data; and

a data processing system configured to provide a set of deblurred images using captured images and each of the blur parameters from the stored set.

16. The system of claim 15 , wherein the data processing system provides the set of deblurred images by:

initializing a candidate deblurred image;

determining a plurality of differential images representing differences between neighboring pixels in the candidate deblurred image;

determining a combined differential image by combining the differential images; and

updating the candidate deblurred image responsive to the captured image, the blur kernel, the candidate deblurred image and the combined differential image.

17. The system of claim 15 , wherein the data processing system is further configured to use the set of deblurred images to determine range information for the objects in the scene.

18. A method comprising:

providing an image capture device having an image sensor, at least two coded apertures having different spatial frequency responses, and a lens;

storing in a memory a set of blur parameters derived from range calibration data for each coded aperture, using a set of blur parameters derived from calibration data at a set of range values, such that there is a set of blur parameters for each coded aperture at each corresponding range value, wherein the sets of blur parameters corresponding to each coded aperture are associated with overlapping range intervals;

capturing images of the scene having a plurality of objects using each of the coded apertures; and

providing a set of deblurred images using the captured images from each coded aperture and each of the blur parameters from the stored set.