EP0652671A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Mapping colour digital image
Assignee: International Business Machines Corp
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Filing: 1994-10-05
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Granted: —
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Expires: 2014-10-05
Abstract
Abstract A system and method for digital video imaging is provided for mapping a digitized image defined by at least a first and second color component (66,68),comprising selecting a dither pattern (70); selecting a complementary dither pattern (72); generating an altered first color component (80) from the first color component and the dither pattern; and generating an altered second color component (82) from the second color component and the complementary dither pattern. Thus for example, complementary dither patterns (70,72) are applied to green and magenta components of the image. The complement nulls out the dither pattern from visual perception. Green and magenta color components of the image switching out of phase with one another cancel dither frequency from luminance. Chrominance alternatively switches between green and magenta, thereby substituting chrominance noise for luminance noise and also thereby effectively reducing overall perceived image noise. In a preferred embodiment the patterns are applied to permit rapid palette mapping with an improved palette, wherein the number of color states are non-integer powers of two (eg 7, 9 and 4 states of red, green and blue respectively).
Inventors
- 👤 Albert Durr Edgar
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 19:33
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/52; H04N1/64; H04N1/648
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
99 words
A method for mapping an input digital image defined by at least first and second color components (66, 68) to an output digital image also defined by at least first and second color components (80, 82), said method comprising the steps of: selecting a dither pattern (70) and a complementary dither pattern (72); generating the first color component of said output image from said first color component of the input image and said dither pattern; and generating the second color component of said output image from said second color component of the input image and said complementary dither pattern.
Claim 2
Dependent Claim
32 words
The method of Claim 1 wherein said step of generating the first color component of said output image comprises adding the dither pattern to the first color component of the input image.
Claim 3
Dependent Claim
33 words
The method of Claim 2 wherein said step of generating the second color component of said output image comprises adding the complementary dither pattern to the second color component of the input image.
Claim 4
Independent Claim
55 words
The method of any preceding claim, wherein said input image and said output image are both defined by first, second and third colour components, and said method further comprises the step of: generating the third color component of said output image from said third color component of the input image and said complementary dither pattern.
Claim 5
Independent Claim
143 words
The method of any of claims 1 to 3, wherein said input image and said output image are both defined by at least a first, second, and third color component, each having a corresponding first, second, and third visual sensitivity, said method comprising the steps of: selecting a first, second, and third dither pattern, the magnitude of each being weighted according to the corresponding one of said first, second, and third visual sensitivities; generating the first color component of said output image from said first color component of the input image and said first dither pattern; generating the second color component of said output image from said second color component of the input image and said second dither pattern; and generating the third color component of said output image from said third color component of the input image and said third dither pattern.
Claim 6
Dependent Claim
21 words
The method of claim 4 or 5, wherein said first, second, and third color components represent green, red, and blue respectively.
Claim 7
Independent Claim
22 words
The method of any preceding claim, further comprising the step of displaying the output image by combining all the color components thereof.
Claim 8
Dependent Claim
39 words
The method of claim 7, comprising the step of determining a luminance and chrominance factor from the color components, and selecting the magnitude of said dither patterns to minimize the effect of said dither pattern on the luminance factor.
Claim 9
Independent Claim
113 words
A method as claimed in any preceding claim, wherein the output image comprises a set of pixels, each pixel containing a reference to a colour in a palette, said palette containing a set of colours, each colour including a red color component, the method further including the steps of: defining (160) a binary representation of the red color component of the input image; shifting said binary representation; obtaining (162) the difference between said binary representation and said shifted binary representation; selecting (166) bits from said difference; shifting said selected bits; and determining (168) the red color component of said output image as the sum of the selected bits and said shifted selected bits.
Claim 10
Dependent Claim
101 words
Apparatus for mapping an input digital image defined by at least first and second color components (66, 68) to an output digital image also defined by at least first and second color components (80, 82), said apparatus comprising: means for selecting a dither pattern (70) and a complementary dither pattern (72); means for generating the first color component of said output image from said first color component of the input image and said dither pattern; and means for generating the second color component of said output image from said second color component of the input image and said complementary dither pattern.
Claim 11
Dependent Claim
144 words
The apparatus of claim 10, wherein said input image and said output image are both defined by at least a first, second, and third color component, each having a corresponding first, second, and third visual sensitivity, said apparatus comprising: means for selecting a first, second, and third dither pattern, the magnitude of each being weighted according to the corresponding one of said first, second, and third visual sensitivities; means for generating the first color component of said output image from said first color component of the input image and said first dither pattern; means for generating the second color component of said output image from said second color component of the input image and said second dither pattern; and means for generating the third color component of said output image from said third color component of the input image and said third dither pattern.
Claim 12
Dependent Claim
19 words
The apparatus of claim 11, wherein said first, second, and third color components represent green, red, and blue respectively.
Claim 13
Dependent Claim
43 words
The apparatus of claim 10, 11, or 12, comprising means for determining a luminance and chrominance factor from the color components, and means for selecting the magnitude of said dither patterns to minimize the effect of said dither pattern on the luminance factor.
References Cited (Backward Citations)
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