Color reduction and conversion using an ordinal lookup table
First Claim
1. A computer-implemented method for converting a color image composed of color pixels, comprising the steps of:
- (a) receiving components of a color pixel of the color image;
(b) truncating most-significant bits from each component of the color pixel;
(c) combining the most-significant truncated bits to form a color number, the color number representing an index to a nearest-color map;
(d) generating an index to a color palette using the nearest-color map index, the color palette containing a plurality of colors; and
(e) accessing one of the plurality of colors to represent the color pixel using the color palette index.
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Accused Products
Abstract
A color image signal is reduced and converted. Dithering the remainder is an embodiment. For example a pixel value is separated into its pixel components. Each component is further split into most-significant bit (MSB) and least-significant bit (LSB) parts. The MSBs from each component are combined to provide a color number. The color number is an index to a nearest-color map. Each entry in the nearest-color map is an index to a spectrum color palette having color entries. The spectrum color palette is an evenly divided spectrum of the colors displayable on an associated video display system. The particular color accessed in the color spectrum palette by the color palette is used for the pixel in the image being reduced and converted. In an embodiment, the LSBs of each color component are dithered. If the value of the LSBs of a color component are greater than a dither threshold value, a one is added to the MSBs of the color, prior to the MSB values being combined into the color number.
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Citations
42 Claims
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1. A computer-implemented method for converting a color image composed of color pixels, comprising the steps of:
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(a) receiving components of a color pixel of the color image; (b) truncating most-significant bits from each component of the color pixel; (c) combining the most-significant truncated bits to form a color number, the color number representing an index to a nearest-color map; (d) generating an index to a color palette using the nearest-color map index, the color palette containing a plurality of colors; and (e) accessing one of the plurality of colors to represent the color pixel using the color palette index. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus for converting a color image composed of color pixels, comprising:
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(a) means for receiving components of a color pixel of the color image; (b) means for truncating most-significant bits from each component of the color pixel; (c) means for combining the most-significant truncated bits to form a color number, the color number representing an index to a nearest-color map; (d) means for generating an index to a color palette using the nearest-color map index, the color palette containing a plurality of colors; and (e) means for accessing one of the plurality of colors to represent the color pixel using the color palette index. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A storage medium encoded with machine-readable computer program code for converting a color image composed of color pixels, comprising:
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(a) means for causing a computer to receive components of a color pixel of the color image; (b) means for causing the computer to truncate most-significant bits from each component of the color pixel; (c) means for causing the computer to combine the most-significant truncated bits to form a color number, the color number representing an index to a nearest-color map; (d) means for causing the computer to generate an index to a color palette using the nearest-color map index, the color palette containing a plurality of colors; and (e) means for causing the computer to access one of the plurality of colors to represent the color pixel using the color palette index. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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Specification