Systems and methods for synthesizing higher resolution images using a set of images containing a baseline image
View Patent ↗Systems and methods for implementing array cameras configured to perform super-resolution processing to generate higher resolution super-resolved images using a plurality of captured images and lens stack arrays that can be utilized in array cameras are disclosed. An imaging device in accordance with one embodiment of the invention includes at least one imager array, and each imager in the array comprises a plurality of light sensing elements and a lens stack including at least one lens surface, where the lens stack is configured to form an image on the light sensing elements, control circuitry configured to capture images formed on the light sensing elements of each of the imagers, and a super-resolution processing module configured to generate at least one higher resolution super-resolved image using a plurality of the captured images.
1. A method of synthesizing a higher resolution image from a plurality of images captured from different viewpoints, comprising:
normalizing a set of images using calibration data stored in a storage device using an address conversion module, where:
the set of images comprises a plurality of images that are:
captured from different viewpoints and include sampling diversity;
include different occlusions sets;
wherein 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; and
the set of images includes:
images captured using the same imaging characteristics;
images captured using different imaging characteristics; and
a first image that captures pixels around an edge of a foreground object that is visible in a baseline image and is in the occlusion set of a second image captured using the same imaging characteristics as the first imager;
detecting and metering parallax using a parallax confirmation and measurement module, where detecting and metering parallax comprises ignoring pixels in the images that are in an exposed occlusion set;
aligning portions of images captured by different imagers to compensate for parallax using an image pixel correlation module based upon the detected and metered parallax and the stored calibration data; and
obtaining a higher resolution image having a resolution that is higher than the resolutions of the images in the set of images using a super-resolution module, where color information around the edge of the foreground object that is visible in the baseline image and in the occlusion set of the second image is reconstructed in the higher resolution image using the pixels captured by the first image.
2. The method 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 method of claim 1 , further comprising performing normalization of the color planes of the set of images using an upstream pipeline processing module.
4. The method of claim 1 , further comprising performing a process to adjust the set of images using an upstream pipeline processing module, where the process is selected from the group consisting of:
black level calculation and adjustments;
fixed noise compensation;
optical point spread function deconvolution;
noise reduction;
lateral color correction; and
crosstalk reduction.
5. The method of claim 1 , further comprising performing temperature normalization using an upstream pipeline processing module based upon a temperature measurement.
6. The method of claim 5 , wherein performing temperature normalization comprises performing a refractive index normalization using a stored point spread function selected based upon the temperature measurement.
7. The method of claim 1 , wherein detecting and metering parallax comprises determining the parallax that yields the highest correlation between pixels from images captured using same imaging characteristics accounting for the positions of the imagers that captured the images.
8. The method of claim 7 , wherein determining the parallax that yields the highest correlation between pixels from images captured using similar integration time conditions comprises performing pair-wise measurements to determine pixel correlation for different parallax-induced shifts.
9. The method of claim 8 , wherein determining the parallax that yields the highest correlation between pixels from images captured using similar integration time conditions further comprises keeping track of various pair-wise measurements and calculating a parallax difference that yields the highest correlation as the best least squares fit of the pair-wise measurements.
10. The method of claim 1 , wherein aligning portions of images captured by different imagers to compensate for parallax using an image pixel correlation module further comprises determining appropriate X and Y offsets to be applied to logical pixel address calculations using an address conversion module based upon the detected and metered parallax and the stored calibration data.
11. The method of claim 1 , wherein obtaining a higher resolution image having a resolution that is higher than the resolutions of the images in the set of images comprises fusing the aligned image portions.
12. The method of claim 11 , wherein image fusion is performed by interpolating luminance information from the aligned image portions to each grid point on the higher resolution image.
13. The method of claim 11 , wherein obtaining a higher resolution image having a resolution that is higher than the resolutions of the images comprises performing super-resolution processing on the fused image portions to synthesize a super-resolution image.
14. The method of claim 1 , wherein obtaining a higher resolution image having a resolution that is higher than the resolutions of the images in the set of images comprises performing a super-resolution processing on the aligned image portions to synthesize a super-resolution image.
15. The method of claim 1 , further comprising generating a depth map using the parallax confirmation and measurement module.
16. The method of claim 15 , further comprising selecting 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 using the super-resolution processing module.
17. The method of claim 11 , wherein:
images in the set of images are captured with different exposure times; and
normalizing a set of images further comprises linearizing the camera response in the images based upon exposure time.
18. The method of claim 1 , further comprising:
capturing the set of images using an array of imagers;
wherein each imager includes a spectral 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.
19. The method of claim 1 , wherein the address conversion module, the parallax confirmation and measurement module, the image pixel correlation module, and the super-resolution module are implemented using a general-purpose computer selectively reconfigured by a computer program stored in the computer.
20. A method of synthesizing a higher resolution image from a plurality of images captured from different viewpoints, comprising:
normalizing a set of images using calibration data stored in a storage device using an address conversion module, where the set of images comprises a plurality of images that are:
captured from different viewpoints and include sampling diversity;
include different occlusions sets;
wherein 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; and the set of images includes:
images captured using the same imaging characteristics;
images captured using different imaging characteristics;
a first image that captures pixels around an edge of a foreground object that is visible in a baseline image and is in the occlusion set of a second image captured using the same imaging characteristics as the first imager;
detecting and metering parallax using a parallax confirmation and measurement module, where detecting and metering parallax comprises ignoring pixels in the images that are in an exposed occlusion set;
aligning portions of images captured by different imagers to compensate for parallax using an image pixel correlation module based upon the detected and metered parallax and the stored calibration data;
obtaining a higher resolution image having a resolution that is higher than the resolutions of the images in the set of images using a super-resolution module, where color information around the edge of the foreground object that is visible in the baseline image and in the occlusion set of the second image is reconstructed in the higher resolution image using the pixels captured by the first image; and
generating a depth map for the higher resolution image using the parallax confirmation and measurement module;
wherein the higher resolution image is obtained by:
fusing the aligned image portions; and
performing super-resolution processing on the fused image portions to synthesize a super-resolution image.