Combined color cast removal and contrast enhancement for digital color images
First Claim
1. A method for digitally processing a digital image under control of a user so as to simultaneously control an amount of color cast removal and an amount of color contrast enhancement performed on the digital image, said method comprising:
- providing a user interface which includes a control element having a single degree of freedom, the single degree of freedom for permitting coupled control over color cast removal and contrast enhancement;
digitally processing the digital image; and
responding to user adjustment of the control element by simultaneous and coupled variation of a degree of color cast removal and an amount of color contrast enhancement performed on the digital image in said digital processing step.
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Accused Products
Abstract
An original image is processed while permitting a user to control an amount of color cast removal and an amount of color contrast enhancement performed on the original image. A user interface, which includes a control element having a single degree of freedom, is provided. User adjustment of the control element is responded to by simultaneously varying the degree of color cast removal and the amount of color contrast enhancement performed on the original image. In a further embodiment, an original image is processed so as to automatically remove color cast from the original image. According to this embodiment contrast is reduced for certain very dark pixels and very bright pixels, and enhanced for the remainder. In a still further embodiment, an original image is processed so as to automatically enhance color contrast in the original image. According to this embodiment, a first mapping of intensity levels is performed if the image is not both highkey and lowkey, and a second mapping is performed if the image is both highkey and lowkey.
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Citations
24 Claims
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1. A method for digitally processing a digital image under control of a user so as to simultaneously control an amount of color cast removal and an amount of color contrast enhancement performed on the digital image, said method comprising:
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providing a user interface which includes a control element having a single degree of freedom, the single degree of freedom for permitting coupled control over color cast removal and contrast enhancement;
digitally processing the digital image; and
responding to user adjustment of the control element by simultaneous and coupled variation of a degree of color cast removal and an amount of color contrast enhancement performed on the digital image in said digital processing step. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for digitally processing an original image so as to automatically remove color cast from the original image, said method comprising:
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obtaining pixel intensity levels for each color component i in an original image;
separately mapping the pixel intensity levels for each color component i to new pixel intensity levels for that color component by (a) determining a value x0 based on the darkest di percent of pixels, (b) mapping pixels darker than x0 to a small first range of dark intensity levels, (c) determining a value x1 based on the brightest bi percent of pixels, (d) mapping pixels brighter than x1 to a small second range of bright intensity levels, and (e) mapping the remainder of the pixels to fall between the first and second ranges, where di and bi are numbers pre-selected for each color component i; and
creating a new image using the new pixel intensity levels for each of the color components. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for digitally processing each of multiple different color components of a digital image so as to automatically enhance color contrast in the digital image, said method comprising:
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designating the digital image as highkey only if, for each color component in the digital image, there exists a sufficient percentage of pixels having a pixel intensity level for that color component which is greater than or equal to a first threshold intensity value;
designating the digital image as lowkey only if, for each color component in the digital image, there exists a sufficient percentage of pixels having a pixel intensity level for that color component which is less than or equal to a second threshold intensity value;
performing a first mapping for each color component of the digital image if the digital image is not both highkey and lowkey; and
performing a second mapping for each color component of the digital image if the digital image is both highkey and lowkey, wherein the second mapping is different than the first mapping, and wherein the second mapping enhances contrast for a range of the brightest pixels and a range of the darkest pixels and reduces contrast for pixels having an intensity between the ranges of darkest and brightest pixels for which contrast is enhanced. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification