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US5905490A
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Generating color-correction look-up-table addresses by multi-level half-toning
Assignee: Seiko Epson Corp
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Filing: 1996-02-26
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Granted: 1999-05-18
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Expires: 2016-02-26
Abstract
Abstract In generating instructions for a printer to render a digitally represented image, addresses for a color-correction look-up table that sparsely samples the source-image color space are generated from the source image by multi-level dithering, and no interpolation is performed to generate the color-corrected image from the values thus fetched from the table, even though it samples the source-image color space only sparsely. In a system in which dithering is also used to generate display commands from the corrected image's pixel values, the effective color resolution is essentially the same as that which would have resulted from interpolation instead of table-look-up-input dithering, but the computation cost is significantly less.
Inventors
- 👤 Joseph Shu
- 👤 Chia-Hsin Li
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:35
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6027; G; G09; G09G; G09G5/00; G09G5/02; H04N1/52; H04N1/6016; H04N1/6019; G09G3/00; G09G3/20; G09G3/2007; G09G3/2044; G09G3/2051; G09G3/2059
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
96 words
A method of operating a display device to render a source image consisting of relatively fine-resolution pixel values comprising the steps of: (a) generating a conversion-input image consisting of coarser-value-resolution pixel values by performing multi-level half-toning operation on the source image; (b) obtaining a converted image by employing the pixel values of the conversion-input image to address a look-up table containing conversion values; (c) performing a second halftoning operation of the converted image from step (b); and (d) operating the display device to generate a display in accordance with the halftoned converted image of step (c).
Claim 2
Independent Claim
96 words
A method of operating a display device to render a source image consisting of relatively fine-resolution pixel values comprising the steps of: (a) generating a conversion-input image consisting of coarser-value-resolution pixel values by performing multi-level half-toning operation on the source image; (b) obtaining a converted image by employing the pixel values of the conversion-input image to address a look-up table containing conversion values; (c) performing a second halftoning operation of the converted image from step (b); and (d) operating the display device to generate a display in accordance with the halftoned converted image of step (c).
Claim 3
Dependent Claim
22 words
A method as defined in claim 1 wherein the step of operating the display device comprises: transmitting display-command values to the printer.
Claim 4
Dependent Claim
15 words
A method as defined in claim 2 wherein the source image is a color image.
Claim 5
Dependent Claim
22 words
A method as defined in claim 2 wherein the multi-level and second half-toning operations are performed in accordance with dispersed-dot dither matrices.
Claim 6
Dependent Claim
42 words
A method as defined in claim 2 wherein: the first and second half-toning operations are performed in accordance with clustered-dot dither matrices having respective cluster spatial frequencies; and one of those spatial frequencies is equal to or a harmonic of the other.
Claim 7
Dependent Claim
15 words
A method as defined in claim 5 wherein the source image is a color image.
Claim 8
Dependent Claim
46 words
A method as defined in claim 5 wherein the cluster spatial frequency of the dither matrix in accordance with which the multi-level half-toning operation is performed is half the cluster spatial frequency of the dither matrix in accordance with which the second half-toning operation is performed.
Claim 9
Dependent Claim
15 words
A method as defined in claim 1 wherein the source image is a color image.
Claim 10
Independent Claim
212 words
An apparatus for operating an image-presenting mechanism to present a source image, which apparatus comprises: A) image-revision circuitry responsive to electrical source-image signals representing the source image for performing a sequence of at least one image-revision step, in which sequence each image-revision step receives an input image consisting of input pixels and produces therefrom an output image consisting of output pixels, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and one said image-revision step is a correction operation in which: i) the input image of the correction operation consists of relatively fine-resolution pixel values; and ii) the correction operation comprises the steps of: a) generating a conversion-input image consisting of coarser-value-resolution pixel values by performing a multi-level half-toning operation on the correction operation's input image; and b) obtaining the correction operation's output image by employing the pixel values of the conversion-input image to address a look-up table containing conversion values; c) performing a second half-toning operation of the output image of step (b); and B) output circuitry responsive to the image-revision circuitry for applying to the image-presenting mechanism electrical command signals that represent the output image produced by last image-revision step.
Claim 11
Independent Claim
212 words
An apparatus for operating an image-presenting mechanism to present a source image, which apparatus comprises: A) image-revision circuitry responsive to electrical source-image signals representing the source image for performing a sequence of at least one image-revision step, in which sequence each image-revision step receives an input image consisting of input pixels and produces therefrom an output image consisting of output pixels, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and one said image-revision step is a correction operation in which: i) the input image of the correction operation consists of relatively fine-resolution pixel values; and ii) the correction operation comprises the steps of: a) generating a conversion-input image consisting of coarser-value-resolution pixel values by performing a multi-level half-toning operation on the correction operation's input image; and b) obtaining the correction operation's output image by employing the pixel values of the conversion-input image to address a look-up table containing conversion values; c) performing a second half-toning operation of the output image of step (b); and B) output circuitry responsive to the image-revision circuitry for applying to the image-presenting mechanism electrical command signals that represent the output image produced by last image-revision step.
Claim 12
Dependent Claim
44 words
An apparatus as defined in claim 9 wherein: A) the multi-level and second half-toning operations are performed in accordance with clustered-dot dither matrices having respective cluster spatial frequencies; and B) one of those spatial frequencies is equal to or a harmonic of the other.
Claim 13
Dependent Claim
44 words
An apparatus as defined in claim 10 wherein the cluster spatial frequency of the dither matrix with which the multi-level half-toning operation is performed is half the cluster spatial frequency of the dither matrix in accordance with which the further half-toning operation is performed.
Claim 14
Dependent Claim
15 words
An apparatus as defined in claim 10 wherein the source image is a color image.
Claim 15
Dependent Claim
22 words
An apparatus as defined in claim 9 wherein the multi-level and second half-toning operations are performed in accordance with dispersed-dot dither matrices.
Claim 16
Dependent Claim
15 words
An apparatus as defined in claim 9 wherein the source image is a color image.
Claim 17
Dependent Claim
221 words
An imaging apparatus comprising: A) an image-presenting mechanism for applying an imaging agent to a medium in accordance with electrical command signals applied thereto; B) image-revision circuitry responsive to electrical source-image signals representing the source image for performing a sequence of at least one image-revision step, in which sequence each image-revision step receives an input image consisting of input pixels and produces therefrom an output image consisting of output pixels, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and one said image-revision step is a correction operation in which: i) the input image of the correction operation consists of relatively fine-resolution pixel values; and ii) the correction operation comprises the steps of: a) generating a conversion-input image consisting of coarser-value-resolution pixel values by performing a multi-level half-toning operation on the correction operation's input image; and b) obtaining the correction operation's output image by employing the pixel values of the conversion-input image to address a look-up table containing conversion values; c) performing a second half-toning operation of the output image of step (b); and B) output circuitry responsive to the image-revision circuitry for applying to the image-presenting mechanism electrical command signals that represent the output image produced by last image-revision step.
Claim 18
Dependent Claim
221 words
An imaging apparatus comprising: A) an image-presenting mechanism for applying an imaging agent to a medium in accordance with electrical command signals applied thereto; B) image-revision circuitry responsive to electrical source-image signals representing the source image for performing a sequence of at least one image-revision step, in which sequence each image-revision step receives an input image consisting of input pixels and produces therefrom an output image consisting of output pixels, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and one said image-revision step is a correction operation in which: i) the input image of the correction operation consists of relatively fine-resolution pixel values; and ii) the correction operation comprises the steps of: a) generating a conversion-input image consisting of coarser-value-resolution pixel values by performing a multi-level half-toning operation on the correction operation's input image; and b) obtaining the correction operation's output image by employing the pixel values of the conversion-input image to address a look-up table containing conversion values; c) performing a second half-toning operation of the output image of step (b); and B) output circuitry responsive to the image-revision circuitry for applying to the image-presenting mechanism electrical command signals that represent the output image produced by last image-revision step.
Claim 19
Dependent Claim
45 words
An imaging apparatus as defined in claim 15 wherein: A) the multi-level and second half-toning operations are performed in accordance with clustered-dot dither matrices having respective cluster spatial frequencies; and B) one of those spatial frequencies is equal to or a harmonic of the other.
Claim 20
Dependent Claim
45 words
An imaging apparatus as defined in claim 16 wherein the cluster spatial frequency of the dither matrix with which the multi-level half-toning operation is performed is half the cluster spatial frequency of the dither matrix in accordance with which the second half-toning operation is performed.
Claim 21
Dependent Claim
16 words
An imaging apparatus as defined in claim 16 wherein the source image is a color image.
Claim 22
Dependent Claim
23 words
An imaging apparatus as defined in claim 15 wherein the multi-level and second half-toning operations are performed in accordance with dispersed-dot dither matrices.
Claim 23
Dependent Claim
16 words
An imaging apparatus as defined in claim 15 wherein the source image is a color image.
Claim 24
Dependent Claim
14 words
An imaging apparatus as defined in claim 15 wherein image-presenting mechanism is a printer.
Claim 25
Dependent Claim
229 words
A storage medium containing instructions readable by a computer to configure the computer to function as a printer driver for operating a printer to present a source image, which printer driver includes: A) image-revision circuitry responsive to electrical source-image signals representing the source image for performing a sequence of at least one image-revision step, in which sequence each image-revision step receives an input image consisting of input pixels and produces therefrom an output image consisting of output pixels, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and one said image-revision step is a correction operation in which: i) the input image of the correction operation consists of relatively fine-resolution pixel values; and ii) the correction operation comprises the steps of: a) generating a conversion-input image consisting of coarser-value-resolution pixel values by performing a multi-level half-toning operation on the correction operation's input image; and b) obtaining the correction operation's output image by employing the pixel values of the conversion-input image to address a look-up table containing conversion values; c) performing a second half-toning operation of the output image of step (b); and B) output circuitry responsive to the image-revision circuitry for applying to the image-presenting mechanism electrical command signals that represent the output image produced by last image-revision step.
Claim 26
Dependent Claim
229 words
A storage medium containing instructions readable by a computer to configure the computer to function as a printer driver for operating a printer to present a source image, which printer driver includes: A) image-revision circuitry responsive to electrical source-image signals representing the source image for performing a sequence of at least one image-revision step, in which sequence each image-revision step receives an input image consisting of input pixels and produces therefrom an output image consisting of output pixels, the input image of the first image-revision step is the source image, the input image of any subsequent image-revision step is the output image of the preceding image-revision step, and one said image-revision step is a correction operation in which: i) the input image of the correction operation consists of relatively fine-resolution pixel values; and ii) the correction operation comprises the steps of: a) generating a conversion-input image consisting of coarser-value-resolution pixel values by performing a multi-level half-toning operation on the correction operation's input image; and b) obtaining the correction operation's output image by employing the pixel values of the conversion-input image to address a look-up table containing conversion values; c) performing a second half-toning operation of the output image of step (b); and B) output circuitry responsive to the image-revision circuitry for applying to the image-presenting mechanism electrical command signals that represent the output image produced by last image-revision step.
Claim 27
Dependent Claim
45 words
A storage medium as defined in claim 22 wherein: A) the multi-level and second half-toning operations are performed in accordance with clustered-dot dither matrices having respective cluster spatial frequencies; and B) one of those spatial frequencies is equal to or a harmonic of the other.
Claim 28
Dependent Claim
45 words
A storage medium as defined in claim 23 wherein the cluster spatial frequency of the dither matrix with which the multi-level half-toning operation is performed is half the cluster spatial frequency of the dither matrix in accordance with which the second half-toning operation is performed.
Claim 29
Dependent Claim
16 words
A storage medium as defined in claim 23 wherein the source image is a color image.
Claim 30
Dependent Claim
23 words
A storage medium as defined in claim 22 wherein the multi-level and further half-toning operations are performed in accordance with dispersed-dot dither matrices.
Claim 31
Dependent Claim
16 words
A storage medium as defined in claim 22 wherein the source image is a color image.
Claim 32
Independent Claim
100 words
A method of operating a display device to render a source image consisting of relatively fine-resolution pixel values comprising the steps of: (a) generating a conversion-input image consisting of coarser-value-resolution pixel values by performing a multi-level dither operation on the source image; (b) obtaining a converted image by employing the pixel values of the conversion-input image to address a color correction look-up table containing conversion values; (c) performing a second single level dither operation of the converted image from step (b); and operating the display device to generate a display in accordance with the halftoned converted image of step (c).
Claim 33
Independent Claim
100 words
A method of operating a display device to render a source image consisting of relatively fine-resolution pixel values comprising the steps of: (a) generating a conversion-input image consisting of coarser-value-resolution pixel values by performing a multi-level dither operation on the source image; (b) obtaining a converted image by employing the pixel values of the conversion-input image to address a color correction look-up table containing conversion values; (c) performing a second single level dither operation of the converted image from step (b); and operating the display device to generate a display in accordance with the halftoned converted image of step (c).
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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) | 2002-05-17 | 2002-11-16 | 2003-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-17 | 2006-11-16 | 2007-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-17 | 2010-11-16 | 2011-05-18 | $7700.00 | Window Closed / Lapsed |