US5477335A
Expired / Lapsed
US
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Method and apparatus of copying of black text on documents using a color scanner
Assignee: Eastman Kodak Co
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Filing: 1992-12-28
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Granted: 1995-12-19
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Expires: 2012-12-28
Abstract
Abstract A document reproduction method and apparatus wherein a scanner scans a document to determine the color components of pixels forming the image information on the document. The color signals generated by the scanner are transformed into lightness space and each pixel is examined as part of a window that includes neighboring pixels. The examination involves a first determination of whether or not the neighboring pixels are white pixels, second and third determinations of whether or not the current pixel is a grey pixel and has high contrast, and a fourth determination of whether or not the window has text structure. In accordance with combination of these determinations, a decision is made to recast the pixel as a pixel to be reproduced with a black colorant to thereby minimize color fringing errors at the edge of text-like information.
Inventors
- 👤 Hwai T. Tai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:21
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/58; H04N1/60; H04N1/62
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
170 words
In a reproduction apparatus for copying color information, the apparatus comprising: first means for scanning an original containing color information to be reproduced and generating signals representing plural color components of pixels of the information scanned; second means for examining a current pixel to determine if the current pixel meets a first criterion of having any neighboring pixels that meet a criterion for a white pixel; third means for examining the current pixel to determine if the current pixel meets a second criterion for a gray pixel; fourth means for testing the current pixel that meets the first criterion but not the second criterion to determine in accordance with a third criterion that the current pixel is in a region of high contrast; fifth means for substituting for the current pixel meeting the first criterion and the third criterion but not meeting the second criterion a signal indicative that the current pixel has only black color content and means, responsive to said signal, for reproducing said current pixel in black.
Claim 2
Dependent Claim
170 words
In a reproduction apparatus for copying color information, the apparatus comprising: first means for scanning an original containing color information to be reproduced and generating signals representing plural color components of pixels of the information scanned; second means for examining a current pixel to determine if the current pixel meets a first criterion of having any neighboring pixels that meet a criterion for a white pixel; third means for examining the current pixel to determine if the current pixel meets a second criterion for a gray pixel; fourth means for testing the current pixel that meets the first criterion but not the second criterion to determine in accordance with a third criterion that the current pixel is in a region of high contrast; fifth means for substituting for the current pixel meeting the first criterion and the third criterion but not meeting the second criterion a signal indicative that the current pixel has only black color content and means, responsive to said signal, for reproducing said current pixel in black.
Claim 3
Dependent Claim
21 words
The apparatus of claim 1 and including means for generating a signal indicative that the current pixel is a text pixel.
Claim 4
Dependent Claim
29 words
The apparatus of claim 2 and including means for processing a pixel indicated to be a text pixel differently from a pixel not indicated to be a text pixel.
Claim 5
Dependent Claim
39 words
The apparatus of claim 1 and including means for examining the current pixel that meets the third criterion to determine if a group of pixels including the current pixel meets a fourth criterion establishing similarity to a text-like structure.
Claim 6
Dependent Claim
46 words
The apparatus of claim 4 and wherein said third means includes means for substituting for the current pixel meeting the first criterion, the third criterion and the fourth criterion but not the second criterion a signal indicative that the current pixel has only black color content.
Claim 7
Dependent Claim
21 words
The apparatus of claim 5 and including means for generating a signal indicative that the current pixel is a text pixel.
Claim 8
Dependent Claim
29 words
The apparatus of claim 6 and including means for processing a pixel indicated to be a text pixel differently from a pixel not indicated to be a text pixel.
Claim 9
Dependent Claim
29 words
The apparatus of claim 1 and wherein said second means examines said current pixel while color of said current pixel is defined in terms of a lightness space representation.
Claim 10
Dependent Claim
29 words
The apparatus of claim 4 and wherein said second means examines said current pixel while color of said current pixel is defined in terms of a lightness space representation.
Claim 11
Dependent Claim
29 words
The apparatus of claim 5 and wherein said second means examines said current pixel while color of said current pixel is defined in terms of a lightness space representation.
Claim 12
Independent Claim
149 words
A method of copying color information, the method comprising the steps of: scanning an original containing color information to be reproduced and generating signals representing plural color components of pixels of the information scanned; examining a current pixel to determine if the current pixel meets a first criterion of having any neighboring pixels that meet a criterion for a white pixel and if the current pixel meets a second criterion for a gray pixel; testing the current pixel which meets the first criterion but not the second criterion to determine in accordance with a third criterion that the current pixel is in a region of high contrast; substituting for the current pixel meeting the first criterion and the third criterion but not the second criterion a signal indicative that the current pixel has only black color content; and in response to said signal reproducing the current pixel in black.
Claim 13
Independent Claim
149 words
A method of copying color information, the method comprising the steps of: scanning an original containing color information to be reproduced and generating signals representing plural color components of pixels of the information scanned; examining a current pixel to determine if the current pixel meets a first criterion of having any neighboring pixels that meet a criterion for a white pixel and if the current pixel meets a second criterion for a gray pixel; testing the current pixel which meets the first criterion but not the second criterion to determine in accordance with a third criterion that the current pixel is in a region of high contrast; substituting for the current pixel meeting the first criterion and the third criterion but not the second criterion a signal indicative that the current pixel has only black color content; and in response to said signal reproducing the current pixel in black.
Claim 14
Dependent Claim
22 words
The method of claim 11 and including the step of generating a signal indicative that the current pixel is a text pixel.
Claim 15
Dependent Claim
30 words
The method of claim 12 and including the step of processing a pixel indicated to be a text pixel differently from a pixel not indicated to be a text pixel.
Claim 16
Dependent Claim
40 words
The method of claim 11 and including the step of examining the current pixel that meets the third criterion to determine if a group of pixels including the current pixel meets a fourth criterion establishing similarity to a text-like structure.
Claim 17
Dependent Claim
43 words
The method of claim 14 and including the step of substituting for the current pixel meeting the first criterion, the third criterion and the fourth criterion but not the second criterion a signal indicative that the current pixel has only black color content.
Claim 18
Dependent Claim
22 words
The method of claim 15 and including the step of generating a signal indicative that the current pixel is a text pixel.
Claim 19
Dependent Claim
30 words
The method of claim 16 and including the step of processing a pixel indicated to be a text pixel differently from a pixel not indicated to be a text pixel.
Claim 20
Dependent Claim
38 words
The method of claim 11 and wherein in the step of examining said current pixel for said first criterion and said second criterion a color of said current pixel is defined in terms of a lightness space representation.
Claim 21
Dependent Claim
38 words
The method of claim 14 and wherein in the step of examining said current pixel for said first criterion and said second criterion a color of said current pixel is defined in terms of a lightness space representation.
Claim 22
Dependent Claim
37 words
The method of claim 15 and wherein in the step of examining said current pixel for said first criterion and said second criterion color of said current pixel is defined in terms of a lightness space representation.
References Cited (Backward Citations)
US4554593A
Cited
US4853970A
Cited
US4862283A
Cited
US4958219A
Cited
US5047844A
Cited
US5032903A
Cited
US5251023A
Cited
US5057852A
Cited
US5087981A
Cited
US5331442A
Cited
US5315382A
Cited
US5134666A
Cited
US5185661A
Cited
US5341224A
Cited
US5200831A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-12-18 | 1999-06-19 | 1999-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-18 | 2003-06-19 | 2003-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-18 | 2007-06-19 | 2007-12-19 | $7700.00 | Window Closed / Lapsed |