Image comparison using color histograms
First Claim
Patent Images
1. A method to compare a first image and a second image, the method comprising:
- obtaining a first color histogram for a first set of pixels sampled from the first image;
obtaining a second color histogram for a second set of pixels sampled from the second image;
determining adjusted bin values of the second color histogram;
determining a comparison metric based on differences between bin values of the first color histogram and the adjusted bin values of the second color histogram; and
determining whether the first image and the second image match based on the comparison metric.
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Abstract
Methods, apparatus and articles of manufacture for image comparison using color histograms are disclosed. An example method disclosed herein to compare a first image and a second image comprises obtaining a first color histogram for a first set of pixels sampled from the first image, obtaining a second color histogram for a second set of pixels sampled from the second image, determining a comparison metric based on differences between bin values of the first color histogram and adjusted bin values of the second color histogram, and determining whether the first image and the second image match based on the comparison metric.
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Citations
20 Claims
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1. A method to compare a first image and a second image, the method comprising:
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obtaining a first color histogram for a first set of pixels sampled from the first image; obtaining a second color histogram for a second set of pixels sampled from the second image; determining adjusted bin values of the second color histogram; determining a comparison metric based on differences between bin values of the first color histogram and the adjusted bin values of the second color histogram; and determining whether the first image and the second image match based on the comparison metric. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method to compare a first image and a second image, the method comprising:
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obtaining a first color histogram for a first set of pixels sampled from the first image; obtaining a second color histogram for a second set of pixels sampled from the second image; determining a comparison metric based on differences between bin values of the first color histogram and adjusted bin values of the second color histogram; and determining whether the first image and the second image match based on the comparison metric, wherein the first image is included in a set of reference images, and further comprising; determining a set of comparison metrics corresponding to comparing respective ones of the set of reference images with the second image, each comparison metric being based on differences between bin values of a respective reference color histogram for a respective reference image and respective adjusted bin values of the second color histogram that are determined based on scaled bin values of the second color histogram and the bin values of the respective reference color histogram; identifying a smallest comparison metric among the set of comparison metrics; and determining that the first image and the second image match when the smallest comparison metric corresponds to a comparison of the first image and the second image, and the smallest comparison metric is less than or equal to a threshold.
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9. A tangible machine readable medium comprising machine readable instructions which, when executed, cause a machine to at least:
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obtain a first color histogram for a first set of pixels sampled from a first image; obtain a second color histogram for a second set of pixels sampled from a second image; determine adjusted bin values of the second color histogram; determine a comparison metric based on differences between bin values of the first color histogram and the adjusted bin values of the second color histogram; and determine whether the first image and the second image match based on the comparison metric. - View Dependent Claims (10, 11, 12, 13)
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14. A tangible machine readable medium comprising machine readable instructions which, when executed, cause a machine to at least:
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obtain a first color histogram for a first set of pixels sampled from a first image; obtain a second color histogram for a second set of pixels sampled from a second image; determine a comparison metric based on differences between bin values of the first color histogram and adjusted bin values of the second color histogram; determine whether the first image and the second image match based on the comparison metric, wherein the first image is included in a set of reference images; determine a set of comparison metrics corresponding to comparing respective ones of the set of reference images with the second image, each comparison metric being based on differences between bin values of a respective reference color histogram for a respective reference image and respective adjusted bin values of the second color histogram that are determined based on scaled bin values of the second color histogram and the bin values of the respective reference color histogram; identify a smallest comparison metric among the set of comparison metrics; and determine that the first image and the second image match when the smallest comparison metric corresponds to a comparison of the first image and the second image, and the smallest comparison metric is less than or equal to a threshold.
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15. An apparatus comprising:
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storage to store a set of reference color histograms corresponding to a respective set of reference images; a histogram generator to generate a test color histogram for a set of pixels sampled from an input test image; and a histogram comparator to; determine a set of comparison metrics corresponding to comparing respective ones of the set of reference images with the input test image, respective ones of the comparison metrics being based on differences between bin values of a respective reference color histogram for a respective reference image and respective adjusted bin values of the test color histogram that are determined based on comparing scaled bin values of the test color histogram with the bin values of the respective reference color histogram; and process the set of comparison metrics to determine whether the input test image matches one or more reference images in the set of reference images. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification