Local adaptive histogram equalization
First Claim
1. An image capture device comprising:
- a first image sensor;
a second image sensor; and
an image processor configured to;
receive image data including a first image from the first image sensor and a second image from the second image sensor, the first image and the second image depicting at least a portion of an image scene and exhibiting local intensity variation relative to one another,partition the first image into a plurality of first blocks of pixels,partition the second image into a plurality of second blocks of pixels,determine a pair of corresponding blocks, the pair of corresponding blocks including an identified first block of the plurality of first blocks and an identified second block of the plurality of second blocks, andgenerate equalized local intensity values for pixels included in the identified first block of the first image and the identified second block of the second image, including mapping intensity values of pixels in the first block to intensity values of pixels in the second-block such that a histogram of the intensity values of pixels of the first block are transformed to more closely resemble a histogram of the intensity values of the pixels of the second block.
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Accused Products
Abstract
Certain aspects relate to systems and techniques for performing local intensity equalization on images in a set of images exhibiting local intensity variations. For example, the local intensity equalization can be used to perform accurate region matching and alignment of the images. The images can be partitioned into regions of pixel blocks, for instance based on location, shape, and size of identified keypoints in the images. Regions depicting the same feature in the images can be equalized with respect to intensity. Region matching based on the keypoints in the intensity-equalized regions can be performed with accuracy even in images captured by asymmetric sensors or exhibiting spatially varying intensity.
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Citations
30 Claims
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1. An image capture device comprising:
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a first image sensor; a second image sensor; and an image processor configured to; receive image data including a first image from the first image sensor and a second image from the second image sensor, the first image and the second image depicting at least a portion of an image scene and exhibiting local intensity variation relative to one another, partition the first image into a plurality of first blocks of pixels, partition the second image into a plurality of second blocks of pixels, determine a pair of corresponding blocks, the pair of corresponding blocks including an identified first block of the plurality of first blocks and an identified second block of the plurality of second blocks, and generate equalized local intensity values for pixels included in the identified first block of the first image and the identified second block of the second image, including mapping intensity values of pixels in the first block to intensity values of pixels in the second-block such that a histogram of the intensity values of pixels of the first block are transformed to more closely resemble a histogram of the intensity values of the pixels of the second block. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for processing a set of images, the method comprising:
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receiving image data representing a first image of an image scene; receiving image data representing a second image of at least a portion of the image scene, the second image exhibiting variations in local intensity values relative to local intensity values of the first image; partitioning each of the first image and the second image into a plurality of blocks of pixels; determining a pair of corresponding blocks, the pair of corresponding blocks including a first block of the plurality of blocks of pixels and a second block of the plurality of blocks of pixels, the first block included in the image data representing the first image and the second block included in the image data representing the second image; and generating equalized local intensity values for pixels included in the first block of the first image and pixels included in the second block of the second image comprising generating a mapping of intensity values of pixels in the first block to intensity values of pixels in the second block such that a histogram of the intensity values of pixels of the first block are transformed to more closely resemble a histogram of the intensity values of the pixels of the second block. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. Non-transitory computer-readable medium storing instructions that, when executed, cause an image processor to perform operations comprising:
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receiving image data representing two or more images captured by a first image sensor and a second image sensor; partitioning each of the two or more images into a plurality of blocks of pixels; determining a pair of corresponding blocks, the pair of corresponding blocks including a first block of the plurality of blocks of pixels and a second block of the plurality of blocks of pixels, the first block included in a first image or the two or more images and the second block included in a second image of the two or more images; and generating equalized intensity values for pixels included in the first block of the first image and pixels included in the second block of the second image, including mapping intensity values of pixels in the first block to intensity values of pixels in the second block such that a histogram of the intensity values of pixels of the first block are transformed to more closely resemble a histogram of the intensity values of the pixels of the second block. - View Dependent Claims (23, 24, 25)
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26. An imaging apparatus comprising:
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means for receiving image data representing a first image of an image scene; means for receiving image data representing a second image of at least a portion of the image scene, the second image exhibiting variations in local intensity values relative to local intensity values of the first image; means for partitioning each of the first image and the second image into a plurality of blocks of pixels; means for determining a pair of corresponding blocks, the pair of corresponding blocks including a first block of the plurality of blocks of pixels and a second block of the plurality of blocks of pixels, the first block included in the image data representing the first image and the second block included in the image data representing the second image; and means for generating equalized local intensity values for pixels included in the first block and pixels included in the second block, the means for generating equalized local intensity values comprising means for generating a mapping of intensity values of pixels in the first block to intensity values of pixels in the second block such that a histogram of the intensity values of pixels of the first block are transformed to more closely resemble a histogram of the intensity values of the pixels of the second block. - View Dependent Claims (27, 28, 29, 30)
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Specification