Systems and methods for generating depth maps using light focused on an image sensor by a lens element array
View Patent ↗A camera array, an imaging device and/or a method for capturing image that employ a plurality of imagers fabricated on a substrate is provided. Each imager includes a plurality of pixels. The plurality of imagers include a first imager having a first imaging characteristics and a second imager having a second imaging characteristics. The images generated by the plurality of imagers are processed to obtain an enhanced image compared to images captured by the imagers. Each imager may be associated with an optical element fabricated using a wafer level optics (WLO) technology.
1. A camera array, comprising:
a plurality of imagers configured to capture images of a scene, where the plurality of imagers are formed by:
an image sensor;
a lens element array forming the optics of each of the plurality of imagers, where the optics of each imager comprises at least one lens element and at least one aperture and focuses light onto the image sensor; and
a controller configured to control operation parameters of the plurality of imagers; and
an image processing pipeline module comprising an address conversion module and a parallax confirmation and measurement module;
wherein the address conversion module is configured to normalize a set of images captured by the plurality of imagers using calibration data stored in a storage device;
wherein the parallax confirmation and measurement module is configured to measure parallax using images captured by the plurality of imagers and generate a depth map using the measured parallax by:
determining a parallax that yields the highest correlation between pixels from the set of images captured by the plurality of imagers accounting for the positions of the imagers that captured the images by:
performing redundant pair-wise measurements between pixels from different images in the set of images to determine pixel correlation for different parallax-induced shifts;
keeping track of various pair-wise measurements and calculating a parallax difference that yields the highest pixel correlation ignoring pixels in the images that are in an exposed occlusion set; and
generating a depth map using the parallax confirmation and measurement module based upon the measured parallax.
2. The array camera of claim 1 , wherein:
the calibration data indicates mappings between addresses of physical pixels in imagers and logical addresses within an image; and
the address conversion module resolves phase differences between the set of images by converting addresses of physical pixels in imagers to logical addresses.
3. The array camera of claim 1 , wherein the parallax confirmation and measurement module is configured to calculate a parallax difference that yields the highest pixel correlation by determining parallax based upon the set of pair-wise measurements that have the best least squares fit.
4. The array camera of claim 1 , further comprising an image pixel correlation module configured to align portions of images captured by different imagers to compensate for parallax by determining appropriate X and Y offsets to be applied to logical pixel address calculations using the address conversion module based upon the detected and metered parallax and the stored calibration data.
5. The array camera of claim 1 , further comprising:
an image pixel correlation module configured to align portions of different images to compensate for parallax using an image pixel correlation module based upon the measured parallax and the stored calibration data; and
a super-resolution module configured to obtain a higher resolution image having a resolution that is higher than the resolutions of the images in the set of images.
6. The array camera of claim 5 , wherein the super-resolution module is further configured to obtain a higher resolution image having a resolution that is higher than the resolutions of the images in the set of images by fusing the aligned image portions.
7. The array camera of claim 6 , wherein the super-resolution module is further configured to obtain a higher resolution image having a resolution that is higher than the resolutions of the images by performing super-resolution processing on the fused image portions to synthesize a super-resolution image.
8. The array camera of claim 5 , wherein the super-resolution module is further configured to obtain a higher resolution image having a resolution that is higher than the resolutions of the images in the set of images comprises performing super-resolution processing on the aligned image portions to synthesize a super-resolution image.
9. The array camera of claim 5 , wherein the super-resolution module is further configured to select at least one distance as a focal plane and applying blurring to pixels in the higher resolution image with depths in the depth map that are not proximate a focal plane.
10. The array camera of claim 1 , wherein the parallax confirmation and measurement module is further configured to estimate distance to an object visible in the set of images using.
11. The array camera of claim 1 , wherein the parallax confirmation and measurement module is further configured to measure the absolute size and shape of a physical item visible in the set of images using the parallax confirmation and measurement module.
12. The array camera of claim 1 , wherein plurality of imagers is an array of between 2×2 and 6×6 imagers.
13. The array camera of claim 1 , wherein the plurality of imagers form at least a 3×3 configuration of imagers comprising:
an imager having a green filter at the center of a 3×3 configuration of imagers;
two imagers having red filters located on opposite sides of the 3×3 configuration of imagers;
two imagers having blue filters located on opposite sides of the 3×3 configuration of imagers; and
four imagers having green filters surrounding the central imager having a green filter.
14. The array camera of claim 1 , wherein the plurality of imagers is a linear array of imagers.
15. The array camera of claim 14 , wherein the linear array of imagers is selected from the group consisting of: a 1×4 array of imagers; and a 1×10 array of imagers.
16. The array camera of claim 1 , wherein each imager in the plurality of imagers includes a filter selected from the group consisting of a Bayer filter, one or more Blue filters, one or more Green filters, one or more Red filters, one or more shifted spectral filters, one or more near-IR filters, and one or more hyper-spectral filters.
17. The array camera of claim 1 , wherein at least one of the imagers in the plurality of imagers is selected from the group consisting of: a polychromatic imager; and a near-IR imager.
18. The array camera of claim 1 , wherein imagers in the array of imagers have the same resolution.
19. The array camera of claim 1 , wherein the images in the set of images have different resolutions.
20. The array camera of claim 1 , wherein the plurality of imagers capture images that are:
captured from different viewpoints; and
include different occlusions sets, where the occlusion set of a first image is the portion of a scene visible in a second image that is occluded in the first image.
21. The array camera of claim 1 , wherein the image sensor comprises control logic that is a single collection of functions common to all of the plurality of imagers.
22. The array camera of claim 1 , wherein the image sensor comprises control logic that is common to some of the plurality of imagers with a smaller set of functions applicable to each imager.
23. The array camera of claim 1 , wherein the image processing pipeline module is selected from the group consisting of hardware, firmware, software and a combination thereof.
24. A camera array, comprising:
a plurality of imagers configured to capture images of a scene, where the plurality of imagers are formed by:
an image sensor comprising control logic that is a single collection of functions common to all of the plurality of imagers;
a lens element array forming the optics of each of the plurality of imagers, where the optics of each imager comprises at least one lens element and at least one aperture and focuses light onto the image sensor; and
a controller configured to control operation parameters of the plurality of imagers; and
an image processing pipeline module comprising a processor directed by software to:
normalize a set of images captured by the plurality of imagers using calibration data stored in a storage device;
measure parallax using images captured by the plurality of imagers and generate a depth map using the measured parallax by:
determining a parallax that yields the highest correlation between pixels from the set of images captured by the plurality of imagers accounting for the positions of the imagers that captured the images by:
performing redundant pair-wise measurements between pixels from different images in the set of images to determine pixel correlation for different parallax-induced shifts;
keeping track of various pair-wise measurements and calculating a parallax difference that yields the highest pixel correlation ignoring pixels in the images that are in an exposed occlusion set; and
generate a depth map using the parallax confirmation and measurement module based upon the measured parallax.
25. A camera array, comprising:
a plurality of imagers configured to capture images of a scene, where the plurality of imagers are formed by:
an image sensor comprising control logic that is common to some of the plurality of imagers with a smaller set of functions applicable to each imager;
a lens element array forming the optics of each of the plurality of imagers, where the optics of each imager comprises at least one lens element and at least one aperture and focuses light onto the image sensor; and
a controller configured to control operation parameters of the plurality of imagers; and
an image processing pipeline module comprising a processor directed by software to:
normalize a set of images captured by the plurality of imagers using calibration data stored in a storage device;
measure parallax using images captured by the plurality of imagers and generate a depth map using the measured parallax by:
determining a parallax that yields the highest correlation between pixels from the set of images captured by the plurality of imagers accounting for the positions of the imagers that captured the images by:
performing redundant pair-wise measurements between pixels from different images in the set of images to determine pixel correlation for different parallax-induced shifts;
keeping track of various pair-wise measurements and calculating a parallax difference that yields the highest pixel correlation ignoring pixels in the images that are in an exposed occlusion set; and
generate a depth map using the parallax confirmation and measurement module based upon the measured parallax.