Apparatus correcting image by luminance histogram
First Claim
1. An apparatus for correcting images, comprising:
- a real average luminance calculating means for calculating a Real Average Luminance (RAL) of an incoming image from a luminance histogram representing a luminance distribution of pixels of the incoming image;
an optimal average luminance estimating means for obtaining a quantity of light using information with respect to a pickup condition of the incoming image when the incoming image is being picked up, and for estimating an Estimated Optimal Average Luminance (EOAL) from the quantity of light; and
a luminance correcting means for correcting a luminance of pixels of the incoming image based on a luminance difference (Δ
L) between the RAL and the EOAL.
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Abstract
An apparatus and method for selectively increasing contrasts of bright and dark regions and automatically determining an appropriate degree of correction such that the image has a corrected luminance that is closer to an estimated optimal average luminance (EOAL) determined from a quantity of light at pickup. The apparatus for correcting the image comprises a real average luminance calculating means for calculating a Real Average Luminance (RAL) of an incoming image from a luminance histogram representing a luminance distribution of pixels of the incoming image, an optimal average luminance estimating means for obtaining a quantity of light using information with respect to a pickup condition of the incoming image and for estimating the EOAL from the quantity of light, and a luminance correcting means for correcting a luminance of pixels of the incoming image based on a luminance difference (ΔL) between the RAL and the EOAL.
29 Citations
18 Claims
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1. An apparatus for correcting images, comprising:
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a real average luminance calculating means for calculating a Real Average Luminance (RAL) of an incoming image from a luminance histogram representing a luminance distribution of pixels of the incoming image; an optimal average luminance estimating means for obtaining a quantity of light using information with respect to a pickup condition of the incoming image when the incoming image is being picked up, and for estimating an Estimated Optimal Average Luminance (EOAL) from the quantity of light; and a luminance correcting means for correcting a luminance of pixels of the incoming image based on a luminance difference (Δ
L) between the RAL and the EOAL. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for correcting images, comprising:
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generating a luminance histogram representing a luminance distribution of pixels of an incoming image; calculating a Real Average Luminance (RAL) of the incoming image from the luminance histogram; obtaining a quantity of light at pickup (Ev) using information with respect to pickup conditions of the incoming image; estimating an Estimated Optimal Average Luminance (EOAL) using the Ev; calculating a luminance difference (Δ
L) between the EOAL and the RAL; andcorrecting a luminance of pixels of the incoming image by means of a curve having at least first to third points of inflection P1, P2, and P3, determined using the Δ
L. - View Dependent Claims (16, 17, 18)
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Specification