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US5774112A
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US
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Method and apparatus for tone correction of a digital color image with preservation of the chromaticity of the image
Assignee: MediaTek Inc
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Filing: 1996-12-11
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Granted: 1998-06-30
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Expires: 2016-12-11
Abstract
Abstract Midtone correction of RGB pixel values is provided, without changes in chromaticity, by multiplying each color component of a linear RGB representation by a single value. The single value corresponds to an adjustment of the original luminance of the pixel, resulting in no change to the chromaticity of the pixel.
Inventors
- 👤 James M. Kasson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:31
CPC Classifications
G; G09; G09G; G09G5/00; G09G5/02; G09G2340/00; G09G2340/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
190 words
An apparatus for modifying colors of pixels in pixel array that represents a color image, comprising: a source of a pixel array, each pixel in the pixel array including a plurality of color components, each color component representing a respective component of a color space and having a value representing the contribution of the component to a color which the pixel has; means for providing an adjusted single color attribute value in response to a user-selected selected value, attribute means coupled to the source for obtaining a single color attribute value for a pixel by combining the values of the pixel's color components; attribute adjustment means coupled to the attribute means for adjusting the single color attribute value to the adjusted single color attribute value; color adjustment means coupled to the attribute adjustment means for adjusting the color of the pixel by changing the values of the pixel's color components in response to the adjusted single color attribute value; and a monitor drive connected to the color adjustment means for producing a monitor drive signal to cause a monitor to display the pixel in response to the pixel's color components.
Claim 2
Independent Claim
190 words
An apparatus for modifying colors of pixels in pixel array that represents a color image, comprising: a source of a pixel array, each pixel in the pixel array including a plurality of color components, each color component representing a respective component of a color space and having a value representing the contribution of the component to a color which the pixel has; means for providing an adjusted single color attribute value in response to a user-selected selected value, attribute means coupled to the source for obtaining a single color attribute value for a pixel by combining the values of the pixel's color components; attribute adjustment means coupled to the attribute means for adjusting the single color attribute value to the adjusted single color attribute value; color adjustment means coupled to the attribute adjustment means for adjusting the color of the pixel by changing the values of the pixel's color components in response to the adjusted single color attribute value; and a monitor drive connected to the color adjustment means for producing a monitor drive signal to cause a monitor to display the pixel in response to the pixel's color components.
Claim 3
Dependent Claim
18 words
The apparatus of claim 1, wherein the single color attribute value is a value of the pixel's luminance.
Claim 4
Dependent Claim
27 words
The apparatus of claim 2, wherein the color space is RGB (red, green, blue) color space, and the color components are, respectively, red, green, and blue components.
Claim 5
Dependent Claim
14 words
The apparatus of claim 3, wherein the pixel's luminance (Y) is given by: Y'=0.2999R'+0.587G'+0.114B'.
Claim 6
Dependent Claim
79 words
The apparatus of claim 2, wherein the attribute adjustment means includes: means for providing for each possible value of the pixel's luminance, an adjusted value, and means for providing a ratio of each adjusted value to a corresponding value of the pixel's luminance; wherein the color adjustment means changes the values of the pixel's color components by multiplying each value of the pixel's color components by a ratio of an adjusted value to the value of the pixel's luminance.
Claim 7
Dependent Claim
27 words
The apparatus of claim 5, wherein the means for providing a ratio includes a table of adjusted values indexed by all possible values of the pixel's luminance.
Claim 8
Dependent Claim
27 words
The apparatus of claim 6, wherein the color space is RGB (red, green, blue) color space, and the color components are, respectively, red, green, and blue components.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-06-29 | 2001-12-29 | 2002-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-29 | 2005-12-29 | 2006-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-29 | 2009-12-29 | 2010-06-30 | $7700.00 | Window Closed / Lapsed |