Illuminant estimation
First Claim
1. A non-transitory program storage device comprising instructions stored thereon to cause one or more processors to:
- obtain access to a first image having a first set of spectral components;
obtain access to a second image having a second set of spectral components, wherein the first and second images are mutually corresponding images;
select a particular fraction of pixels from each of the first and second images in descending order of brightness; and
generate a chromagenic illuminant estimation based, at least in part, on the selected particular fraction of pixels.
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Abstract
In a method of chromagenic illuminant estimation pixels from mutually-corresponding images with different filtering are compared, a fraction of the brightest pixels being selected for a subsequent chromagenic estimation. The pixels may be at corresponding locations or they may correspond in that their mean brightness is in the same rank order. In one method, in which, in a first preprocessing stage, for a database of m lights Ei(λ) and n surfaces Sj(λ) there is calculated Ti˜QFQ+ where Q1F and QF represent the matrices of unfiltered and filtered sensor responses to the n surfaces under the i th light and + denotes an inverse, and in a second operation stage, given P surfaces in an image and 3×P matrices Q and QF, from these matrices there are chosen the r % brightest pixels giving the matrices Q′ and Q′F, and the scene illuminant Pest is estimated where formula (I) and (II).
9 Citations
20 Claims
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1. A non-transitory program storage device comprising instructions stored thereon to cause one or more processors to:
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obtain access to a first image having a first set of spectral components; obtain access to a second image having a second set of spectral components, wherein the first and second images are mutually corresponding images; select a particular fraction of pixels from each of the first and second images in descending order of brightness; and generate a chromagenic illuminant estimation based, at least in part, on the selected particular fraction of pixels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system, comprising:
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a display; and one or more processors in communication with the display, wherein the one or more processors are programmed to execute instructions to; select a fraction of the brightest pixels from each of a pair of mutually corresponding images; and perform chromagenic illuminant estimation on at least one of the pair of mutually corresponding images, wherein the pair of mutually corresponding images have different sets of spectral components, and wherein the programmed act of selecting the fraction of the brightest pixels comprises executing instructions to select a particular fraction of pixels from each of the mutually corresponding images in descending order of brightness from the brightest pixel in each of the mutually corresponding images. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A method, comprising:
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selecting a fraction of the brightest pixels from each of a pair of mutually corresponding images; and performing chromagenic illuminant estimation on at least one of the pair of mutually corresponding images, wherein the pair of mutually corresponding images have different sets of spectral components, and wherein the act of selecting the fraction of the brightest pixels comprises selecting a particular fraction of pixels from each of the mutually corresponding images in descending order of brightness from the brightest pixel in each of the mutually corresponding images.
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Specification