Systems and methods for parallax detection and correction in images captured using array cameras that contain occlusions using subsets of images to perform depth estimation

A method of synthesizing a higher resolution image from a light field comprising a set of lower resolution images captured from different viewpoints, the method comprising:

• estimating distances to objects within a scene from the light field comprising a set of images captured from different viewpoints using a processor configured by an image processing application, the method comprising:
• selecting a reference viewpoint relative to the viewpoints of the set of images captured from different viewpoints;
• normalizing the set of images to increase the similarity of corresponding pixels within the set of images;
• determining initial depth estimates for pixel locations in an image from the reference viewpoint using at least a subset of the set of images, where an initial depth estimate for a given pixel location in the image from the reference viewpoint is determined by:
• identifying pixels in the at least a subset of the set of images that correspond to the given pixel location in the image from the reference viewpoint based upon expected disparity at a plurality of depths;
• comparing the similarity of the corresponding pixels identified at each of the plurality of depths;
• and
• selecting the depth from the plurality of depths at which the identified corresponding pixels have the highest degree of similarity as an initial depth estimate for the given pixel location in the image from the reference viewpoint;
• identifying corresponding pixels in the set of images using the initial depth estimates;
• comparing the similarity of the corresponding pixels in the set of images to detect mismatched pixels;
• when an initial depth estimate does not result in the detection of a mismatch between corresponding pixels in the set of images, selecting the initial depth estimate as the current depth estimate for the pixel location in the image from the reference viewpoint;
• when an initial depth estimate results in the detection of a mismatch between corresponding pixels in the set of images, selecting the current depth estimate for the pixel location in the image from the reference viewpoint by:
• determining a set of candidate depth estimates using a plurality of different subsets of the set of images;
• identifying corresponding pixels in each of the plurality of subsets of the set of images based upon the candidate depth estimates;
• and
• selecting the candidate depth of the subset having the most similar corresponding pixels as the current depth estimate for the pixel location in the image from the reference viewpoint;
• determining the visibility of the pixels in the set of images from the reference viewpoint by:
• identifying corresponding pixels in the set of images using the current depth estimates;
• and
• determining that a pixel in a given image is not visible in the reference viewpoint when the pixel fails a photometric similarity criterion determined based upon a comparison of corresponding pixels;
• and
• fusing pixels from the set of images using the processor configured by the image processing application based upon the depth estimates to create a fused image having a resolution that is greater than the resolutions of the images in the set of images by:
• identifying the pixels from the set of images that are visible in an image from the reference viewpoint using the visibility information;
• and
• applying scene dependent geometric shifts to the pixels from the set of images that are visible in an image from the reference viewpoint to shift the pixels into the reference viewpoint, where the scene dependent geometric shifts are determined using the current depth estimates;
• and
• fusing the shifted pixels from the set of images to create a fused image from the reference viewpoint having a resolution that is greater than the resolutions of the images in the set of images.

An image processing system, comprising:

• a processor;
• memory containing a set of images captured from different viewpoints and an image processing application;
• wherein the image processing application configures the processor to:
• select a reference viewpoint relative to the viewpoints of the set of images captured from different viewpoints;
• normalize the set of images to increase the similarity of corresponding pixels within the set of images;
• determine initial depth estimates for pixel locations in an image from the reference viewpoint using at least a subset of the set of images, where an initial depth estimate for a given pixel location in the image from the reference viewpoint is determined by:
• identifying pixels in the at least a subset of the set of images that correspond to the given pixel location in the image from the reference viewpoint based upon expected disparity at a plurality of depths;
• comparing the similarity of the corresponding pixels identified at each of the plurality of depths;
• and
• selecting the depth from the plurality of depths at which the identified corresponding pixels have the highest degree of similarity as an initial depth estimate for the given pixel location in the image from the reference viewpoint;
• identify corresponding pixels in the set of images using the initial depth estimates;
• compare the similarity of the corresponding pixels in the set of images to detect mismatched pixels;
• when an initial depth estimate does not result in the detection of a mismatch between corresponding pixels in the set of images, select the initial depth estimate as the current depth estimate for the pixel location in the image from the reference viewpoint;
• when an initial depth estimate results in the detection of a mismatch between corresponding pixels in the set of images, select the current depth estimate for the pixel location in the image from the reference viewpoint by:
• determining a set of candidate depth estimates using a plurality of different subsets of the set of images;
• identifying corresponding pixels in each of the plurality of subsets of the set of images based upon the candidate depth estimates;
• and
• selecting the candidate depth of the subset having the most similar corresponding pixels as the current depth estimate for the pixel location in the image from the reference viewpoint.