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Patent US5528384A successfully refreshed from Google Patents.
US5528384A
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System and method for implementing fast high addressability error diffusion process
Assignee: Xerox Corp
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Filing: 1994-08-03
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Granted: 1996-06-18
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Expires: 2014-08-03
Abstract
Abstract A method and system implements a high addressability characteristic into an error diffusion process. A grey level value representing a pixel is received. The grey level value is interpolated to generate subpixel grey level values which correspond to a second resolution. A threshold circuit thresholds the interpolated grey level value. In parallel to the interpolation circuit and threshold circuit is an error circuit which generates a plurality of possible error values. One of the plurality of possible error values is selected based on the number of subpixels exceeding a threshold value. A portion of the selected error value is then diffused to adjacent pixels on a next scanline.
Inventors
- 👤 David J. Metcalfe
- 👤 Jeng-Nan Shiau
- 👤 Leon C. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:28
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4051; H04N1/4052; H04N1/4053
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
126 words
A method of diffusing an error generated from thresholding a grey level value representing a pixel, comprising the steps of: (a) receiving grey level values representing pixels, each pixel having a single grey level value associated therewith; (b) converting the grey level value of a pixel to a predetermined number of interpolated subpixel values; (c) thresholding each of the interpolated subpixel values; (d) generating a plurality of possible error values in parallel with the conversion and thresholding carried out by said steps (b) and (c); (e) selecting one of the plurality of possible error values based on a number of interpolated subpixels values exceeding a threshold value determined in said step (c); and (f) diffusing the selected error value to grey level values representing adjacent pixels.
Claim 2
Independent Claim
126 words
A method of diffusing an error generated from thresholding a grey level value representing a pixel, comprising the steps of: (a) receiving grey level values representing pixels, each pixel having a single grey level value associated therewith; (b) converting the grey level value of a pixel to a predetermined number of interpolated subpixel values; (c) thresholding each of the interpolated subpixel values; (d) generating a plurality of possible error values in parallel with the conversion and thresholding carried out by said steps (b) and (c); (e) selecting one of the plurality of possible error values based on a number of interpolated subpixels values exceeding a threshold value determined in said step (c); and (f) diffusing the selected error value to grey level values representing adjacent pixels.
Claim 3
Dependent Claim
30 words
The method as claimed in claim 1, wherein said step (b) comprises the substeps of: (b1) computing a first interpolated subpixel value; and (b2) computing a second interpolated subpixel value.
Claim 4
Dependent Claim
78 words
The method as claimed in claim 1, wherein said step (b) further comprises the substep of: (b3) computing a plurality of interpolated subpixel values B n , the interpolated subpixel values B n being equal to P0+n(P1-P0)/N, wherein n is equal to 0 to N-1, P0 is equal to a grey level value of a first pixel, P1 is equal to a grey level value of a second pixel, and N is equal to a high addressability characteristic.
Claim 5
Dependent Claim
51 words
The method as claimed in claim 3, wherein said step (d) comprises the substeps of: (d1) calculating a desired output; (d2) calculating a plurality of possible actual outputs; and (d3) calculating the plurality of possible error values, each error value being equal to the desired output minus a possible actual output.
Claim 6
Dependent Claim
30 words
The method as claimed in claim 1, further comprising the step of: (g) screening the grey level value with a predetermined screen prior to the execution of said step (b).
Claim 7
Independent Claim
159 words
A system for diffusing an error generated from thresholding a grey level value representing a pixel, comprising: input means for receiving grey level values representing pixels, each pixel having a single grey level value associated therewith; high addressability means for converting the grey level value of a pixel to a predetermined number of interpolated subpixel values; threshold means for thresholding each of the interpolated subpixel values and for determining a number of interpolated subpixels values which exceed a threshold value; error means, operatively connected in parallel with said high addressability means and said threshold means, for generating a plurality of possible error values; selecting means, operatively connected to said error means and said threshold means, for selecting one of the plurality of possible error values based on the number of interpolated subpixels values exceeding a threshold value determined by said threshold means; and error diffusing means for diffusing the selected error value to grey level values representing adjacent pixels.
Claim 8
Independent Claim
159 words
A system for diffusing an error generated from thresholding a grey level value representing a pixel, comprising: input means for receiving grey level values representing pixels, each pixel having a single grey level value associated therewith; high addressability means for converting the grey level value of a pixel to a predetermined number of interpolated subpixel values; threshold means for thresholding each of the interpolated subpixel values and for determining a number of interpolated subpixels values which exceed a threshold value; error means, operatively connected in parallel with said high addressability means and said threshold means, for generating a plurality of possible error values; selecting means, operatively connected to said error means and said threshold means, for selecting one of the plurality of possible error values based on the number of interpolated subpixels values exceeding a threshold value determined by said threshold means; and error diffusing means for diffusing the selected error value to grey level values representing adjacent pixels.
Claim 9
Dependent Claim
24 words
The system as claimed in claim 6, wherein said high addressability means computes a first interpolated subpixel value and a second interpolated subpixel value.
Claim 10
Dependent Claim
74 words
The system as claimed in claim 6, wherein said high addressability means further computes a plurality of interpolated subpixel values B n , the interpolated subpixel values B n being equal to P0+n(P1-P0)/N, wherein n is equal to 0 to N-1, P0 is equal to a grey level value of a first pixel, P1 is equal to a grey level value of a second pixel, and N is equal to a high addressability characteristic.
Claim 11
Dependent Claim
55 words
The system as claimed in claim 6, wherein said error means comprises: first means for calculating a desired output; second means for calculating a plurality of possible actual outputs; and third means for calculating the plurality of possible error values, each possible error value being equal to the desired output minus a possible actual output.
Claim 12
Dependent Claim
28 words
The system as claimed in claim 6, further comprising: screening means for screening the grey level value with a predetermined screen prior to conversion by said conversion means.
Claim 13
Independent Claim
73 words
A method of generating an error from a threshold process, comprising the steps of: (a) thresholding a plurality of interpolated subpixel values associated with a pixel; (b) generating a plurality of possible error values in parallel with the thresholding carried out by said step (a); and (c) selecting one of the plurality of possible error values based on a number of interpolated subpixels values exceeding a threshold value determined in said step (a).
Claim 14
Independent Claim
73 words
A method of generating an error from a threshold process, comprising the steps of: (a) thresholding a plurality of interpolated subpixel values associated with a pixel; (b) generating a plurality of possible error values in parallel with the thresholding carried out by said step (a); and (c) selecting one of the plurality of possible error values based on a number of interpolated subpixels values exceeding a threshold value determined in said step (a).
Claim 15
Dependent Claim
30 words
The method as claimed in claim 11, further comprising the step of: (d) diffusing the selected error value to grey level values of pixels adjacent to the pixel being thresholded.
Claim 16
Dependent Claim
48 words
The method as claimed in claim 11, further comprising the steps of: (d) converting a grey level value of a pixel to a predetermined number of interpolated subpixel values; and (e) screening the grey level value with a predetermined screen prior to the execution of said step (d).
Claim 17
Independent Claim
97 words
A system for generating an error from a threshold process, comprising: threshold means for thresholding a plurality of interpolated subpixel values associated with a pixel and for determining a number of interpolated subpixels values which exceed a threshold value; error means, operatively connected in parallel with said threshold means, for generating a plurality of possible error values; and selecting means, operatively connected to said error means and said threshold means, for selecting one of the plurality of possible error values based on the number of interpolated subpixels values exceeding the threshold value determined by said threshold means.
Claim 18
Independent Claim
97 words
A system for generating an error from a threshold process, comprising: threshold means for thresholding a plurality of interpolated subpixel values associated with a pixel and for determining a number of interpolated subpixels values which exceed a threshold value; error means, operatively connected in parallel with said threshold means, for generating a plurality of possible error values; and selecting means, operatively connected to said error means and said threshold means, for selecting one of the plurality of possible error values based on the number of interpolated subpixels values exceeding the threshold value determined by said threshold means.
Claim 19
Dependent Claim
29 words
The system as claimed in claim 14, further comprising: diffusing means for diffusing the selected error value to grey level values of pixels adjacent to the pixel being thresholded.
Claim 20
Dependent Claim
48 words
The system as claimed in claim 14, further comprising: converting means for converting a grey level value of a pixel to a predetermined number of interpolated subpixel values; and screening means for screening the grey level value with a predetermined screen prior to converting by said converting means.
Claim 21
Dependent Claim
170 words
A printing system for rendering marks on a recording medium, comprising: receiving means for receiving a grey level signal corresponding to a pixel; interpolation means for converting the grey level value of a pixel to a predetermined number of interpolated subpixel values; binarization means for binarizing the converted grey level signal so as to output a binary signal and for determining a number of interpolated subpixel values which exceed a threshold value; error means, operatively connected in parallel with said interpolation means and said binarization means, for generating a plurality of possible error values; and selecting means, operatively connected to said error means and said binarization means, for selecting one of the plurality of possible error values based on the number of interpolated subpixel values exceeding a threshold value determined by said binarization means; diffusing means for diffusing the selected error value to grey level signals corresponding to pixels adjacent to the pixel being binarized; and rendering means for converting the binary signal into a mark on the recording medium.
Claim 22
Dependent Claim
170 words
A printing system for rendering marks on a recording medium, comprising: receiving means for receiving a grey level signal corresponding to a pixel; interpolation means for converting the grey level value of a pixel to a predetermined number of interpolated subpixel values; binarization means for binarizing the converted grey level signal so as to output a binary signal and for determining a number of interpolated subpixel values which exceed a threshold value; error means, operatively connected in parallel with said interpolation means and said binarization means, for generating a plurality of possible error values; and selecting means, operatively connected to said error means and said binarization means, for selecting one of the plurality of possible error values based on the number of interpolated subpixel values exceeding a threshold value determined by said binarization means; diffusing means for diffusing the selected error value to grey level signals corresponding to pixels adjacent to the pixel being binarized; and rendering means for converting the binary signal into a mark on the recording medium.
References Cited (Backward Citations)
US5121447A
Cited
US5271070A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-06-18 | 1999-12-18 | 2000-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-18 | 2003-12-18 | 2004-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-18 | 2007-12-18 | 2008-06-18 | $7700.00 | Window Closed / Lapsed |