US4992955A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for representing continuous tone and high contrast images on a bilevel display
Assignee: Hitachi Ltd
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Filing: 1988-10-24
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Granted: 1991-02-12
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Expires: 2008-10-24
Abstract
Abstract A half tone display apparatus using a display apparatus of bilevel representation in white and black is provided. The apparatus includes a unit supplied with a multilevel image such as a color image, a device for detecting edges in characters, patterns and photographic images, a unit for deriving a level difference between pixels adjacent to the edge, and a control unit for forcibly displaying a pixel of the edge portion as a white or black pixel for emphasis provided that the level difference is not larger than a predetermined threshold and for applying dither conversion to other pixels.
Inventors
- 👤 Shigeru Yabuuchi
- 👤 Satoshi Yoshizawa
- 👤 Masakazu Ejiri
- 👤 Seiji Kashioka
- 👤 Yasuo Kurosu
- 👤 Hiroaki Aotsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:16
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/387; H04N1/40; H04N1/405; H04N1/4055
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
198 words
A display apparatus for displaying a half tone image on a bilevel display, comprising: means for inputting multi-level image data, including characters, patterns or photographic images, to be displayed on a bilevel display; means for detecting edges in the characters, patterns, or photographic images; edge emphasis means for obtaining a level difference between a noted pixel bordering the edges and a pixel adjacent to the noted pixel and for forcibly defining a display value of the noted pixel as the value of a white or black pixel when the level difference is not larger than a predetermined threshold, whereby contours of the characters, patterns, or photographic images displayed on the bilevel display are emphasized; dither means for applying dither conversion to other pixels not bordering the edges and for determining display values of the other pixels; and portion pixel, provided that the level difference is not larger than a predetermined threshold, and for applying dither conversion to pixels other than edge portion pixels; wherein a dither conversion pattern is used so that adjacent pixels on an odd-numbered raster and an even-numbered raster may be simultaneously displayed as white pixels when a CRT of an interlace scheme is used.
Claim 2
Dependent Claim
198 words
A display apparatus for displaying a half tone image on a bilevel display, comprising: means for inputting multi-level image data, including characters, patterns or photographic images, to be displayed on a bilevel display; means for detecting edges in the characters, patterns, or photographic images; edge emphasis means for obtaining a level difference between a noted pixel bordering the edges and a pixel adjacent to the noted pixel and for forcibly defining a display value of the noted pixel as the value of a white or black pixel when the level difference is not larger than a predetermined threshold, whereby contours of the characters, patterns, or photographic images displayed on the bilevel display are emphasized; dither means for applying dither conversion to other pixels not bordering the edges and for determining display values of the other pixels; and portion pixel, provided that the level difference is not larger than a predetermined threshold, and for applying dither conversion to pixels other than edge portion pixels; wherein a dither conversion pattern is used so that adjacent pixels on an odd-numbered raster and an even-numbered raster may be simultaneously displayed as white pixels when a CRT of an interlace scheme is used.
Claim 3
Dependent Claim
48 words
A display apparatus according to claim 1, further comprising means for selecting any one of three primary colors representing a color that represents a pixel of an input image and for defining the selected primary color as a level of a pixel to be displayed with half tone.
Claim 4
Dependent Claim
56 words
A display apparatus according to claim 1, further comprising means for multiplying three primary colors representing a color that represents a pixel of an input image with respective weighting coefficients, for deriving a total sum of resultant products, and for defining the total sum as a level of a pixel to be displayed with half tone.
Claim 5
Dependent Claim
85 words
A display apparatus according to claim 1, further comprising means for memorizing coordinates of an origin of a first opened window, for rearranging set values of a dither matrix of the first opened window on the basis of coordinates of a window obtained after movement and the coordinates of the origin every time a window is opened so that a phase of a dither pattern within the first opened window may agree with a phase of a dither pattern within the window obtained after movement.
Claim 6
Dependent Claim
21 words
A display apparatus according to claim 1, wherein a dither conversion pattern is utilized to shine pixels in a slant direction.
Claim 7
Dependent Claim
34 words
A display apparatus according to claim 1, further comprising means for deriving element numbers of a dither matrix referred to at dither conversion on the basis of distance from origin coordinates of a window.
Claim 8
Dependent Claim
33 words
A display apparatus according to claim 1, further comprising means capable of changing element numbers of a dither matrix referred to at dither conversion on the basis of origin coordinates of a window.
Claim 9
Dependent Claim
42 words
A display apparatus according to claim 1, wherein a dither conversion pattern is used so that adjacent pixels on an odd-numbered raster and an even-numbered raster may be simultaneously displayed as white pixels when a CRT of an interlace scheme is used.
Claim 10
Dependent Claim
100 words
A display apparatus for displaying half tone images with multiple windows on a bilevel display, comprising: means supplied with a multi-level image such as a color image for detecting edges in characters, patterns, photographic images and the like included in the multi-level image; means for deriving a level difference between pixels adjacent to the edges; and control means for forcibly displaying a pixel of an edge portion as a white or black pixel to emphasize the edge means for displaying a half tone image on the bilevel display by using outputs of said edge emphasis means and said dither means.
Claim 11
Dependent Claim
100 words
A display apparatus for displaying half tone images with multiple windows on a bilevel display, comprising: means supplied with a multi-level image such as a color image for detecting edges in characters, patterns, photographic images and the like included in the multi-level image; means for deriving a level difference between pixels adjacent to the edges; and control means for forcibly displaying a pixel of an edge portion as a white or black pixel to emphasize the edge means for displaying a half tone image on the bilevel display by using outputs of said edge emphasis means and said dither means.
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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) | 1994-02-11 | 1994-08-13 | 1995-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-11 | 1998-08-13 | 1999-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-11 | 2002-08-13 | 2003-02-12 | $7700.00 | Window Closed / Lapsed |