Methods and Systems for Color Preservation with a Color-Modulated Backlight
First Claim
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1. A method for adjusting image code values for backlight variations, said method comprising:
- a) determining backlight intensity values for a plurality of color channels at a pixel location;
b) determining desired pixel output values for said plurality of color channels for a pixel at said pixel location;
c) calculating compensated pixel input values for said plurality of color channels at said pixel based on said desired pixel output values and said backlight intensity values.
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Abstract
Elements of the present invention relate to systems and methods for compensating an image for backlight color variation. Some embodiments comprise compensation for color variation in RGB backlights when backlight color channels use differing gain functions.
166 Citations
20 Claims
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1. A method for adjusting image code values for backlight variations, said method comprising:
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a) determining backlight intensity values for a plurality of color channels at a pixel location; b) determining desired pixel output values for said plurality of color channels for a pixel at said pixel location; c) calculating compensated pixel input values for said plurality of color channels at said pixel based on said desired pixel output values and said backlight intensity values. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for adjusting image code values for backlight variations, said method comprising:
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a) determining a first backlight intensity value for a first color channel of a backlight element corresponding to a pixel; b) determining a first ideal gain value to compensate for said first backlight intensity value; c) determining a first gain equivalent value to compensate for said first backlight intensity value; d) calculating a first gain reduction factor based on said first ideal gain value and said first gain equivalent value; e) determining a second backlight intensity value for a second color channel of said pixel; f) determining a second ideal gain value to compensate for said second backlight intensity value; g) determining a second gain equivalent value to compensate for said second backlight intensity value; h) calculating a second gain reduction factor based on said second ideal gain value and said second gain equivalent value; i) selecting one of said first gain reduction factor and said second gain reduction factor as a selected gain reduction factor, said selecting being based on color preservation; and j) determining an adjusted image color channel code value using an original image code value for a color channel of said pixel, said ideal gain and said selected gain reduction factor. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for adjusting image code values for backlight variations, said method comprising:
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a) determining a first backlight intensity value for a first color channel of a pixel; b) determining a first ideal gain value to compensate for said first backlight intensity value, wherein said first ideal gain value is determined with the relationship, wherein IR is the backlight intensity for said first color channel and γ
is a display gamma value;c) determining a first code-value-dependent gain value to compensate for said first backlight intensity value, said determining a first code-value-dependent gain value comprising using the relationship, wherein {tilde over (x)} is an ideal adjusted code value and is a code-value-dependent transfer function; d) calculating a first gain reduction factor, for said first color channel, using the relationship, wherein α
denotes a specific color channel and x is an image code value and Kα
(x) is the gain reduction factor;e) determining a second backlight intensity value for a second color channel of said pixel; f) determining a second ideal gain value to compensate for said second backlight intensity value, wherein said second ideal gain value is determined with the relationship, wherein IG is the backlight intensity for said second color channel and γ
is a display gamma value;g) determining a second code-value-dependent gain value to compensate for said second backlight intensity value, said determining a second code-value-dependent gain value comprising using the relationship, wherein {tilde over (x)} is an ideal adjusted code value and is a code-value-dependent transfer function; h) calculating a second gain reduction factor, for said second color channel, using the relationship, wherein α
denotes a specific color channel and x is an image code value and Kα
(x) is the gain reduction factor;i) selecting one of said first gain reduction factor and said second gain reduction factor as a selected gain reduction factor based on which factor effects the least gain; and j) determining an adjusted image code value using an original image code value, said ideal gain value and said selected gain reduction factor for one of said first or second color channels.
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Specification