Apparatus and method for error diffusion with dither
First Claim
Patent Images
1. A method of halftoning an original input image having gray-level values to thereby form a reduced-bit output image, comprising:
- adding a first type of passband dither to input pixels of the original input image to form dithered input pixels; and
performing error diffusion on the dithered input pixels using threshold values comprising at least one component, the at least one component being based at least in part on a second type of dither.
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Abstract
The input pixels in an image to be halftoned using error diffusion are dithered using a first type of passband dither. A second type of passband dither may also be added to a thresholding matrix used in halftoning. This second type of passband dither may be the same as the first type of passband dither. In such case, the second type of passband dither is a scaled multiple of the first type of passband dither. The halftoning process may be implemented in an application specific integrated circuit.
12 Citations
17 Claims
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1. A method of halftoning an original input image having gray-level values to thereby form a reduced-bit output image, comprising:
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adding a first type of passband dither to input pixels of the original input image to form dithered input pixels; and performing error diffusion on the dithered input pixels using threshold values comprising at least one component, the at least one component being based at least in part on a second type of dither. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of halftoning an original input image having gray-level values to thereby form a reduced-bit output image, comprising:
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adding a first type of passband dither to input pixels of the original input image to form dithered input pixels; and performing error diffusion on the dithered input pixels using tone-dependent thresholds, wherein the tone-dependent thresholds are indexed by information based on the dithered input pixels.
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15. An application specific integrated circuit (ASIC) for performing error diffusion and configured to:
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add a first type of passband dither to input pixels of the original input image to form dithered input pixels; perform error diffusion on the dithered input pixels using tone-dependent thresholds; and add a second type of passband dither to said tone-dependent thresholds. - View Dependent Claims (16)
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17. An application specific integrated circuit (ASIC) for performing error diffusion and configured to:
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add a first type of passband dither to input pixels of the original input image to form dithered input pixels; perform error diffusion on the dithered input pixels using ton-dependent thresholds; and index tone-dependent thresholds using information based on the dithered input pixels.
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Specification