US4680645A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for rendering gray scale images with variable dot sizes
Assignee: HP Inc
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Filing: 1986-08-25
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Granted: 1987-07-14
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Expires: 2006-08-25
Abstract
Abstract The capability of varying sizes of a dot in a printer is fully exploited to provide a gray scale image of superior quality. Errors in gray level are used to modulate the sizes of the dots in producing the image.
Inventors
- 👤 Gary J. Dispoto
- 👤 Larry R. Mather
- 👤 John D. Meyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:39
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4055; H04N1/4057
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
97 words
A method of generating a gray scale image on a surface comprising a matrix of pixels, the method comprising the steps of: depositing a first dot of a predetermined size on a selected pixel on the surface; determining a gray level error of the deposited first dot; scaling the error and assigning the scaled error to a pixel adjacent to the selected pixel; determining a size of a second dot in response to the scaled error to provide a second dot of a predetermined size; depositing the second dot of a predetermined size on the adjacent pixel.
Claim 2
Independent Claim
97 words
A method of generating a gray scale image on a surface comprising a matrix of pixels, the method comprising the steps of: depositing a first dot of a predetermined size on a selected pixel on the surface; determining a gray level error of the deposited first dot; scaling the error and assigning the scaled error to a pixel adjacent to the selected pixel; determining a size of a second dot in response to the scaled error to provide a second dot of a predetermined size; depositing the second dot of a predetermined size on the adjacent pixel.
Claim 3
Dependent Claim
26 words
The method of claim 1 wherein the step of determining a gray level error further comprises the step of determining the error in optical density units.
Claim 4
Independent Claim
88 words
An apparatus for printing a gray scale image on a surface comprising: means for depositing a first dot of a predetermined size on a selected area of the surface; means for determining an error in gray level in the selected area; means for scaling the error and assigning the scaled error to an area adjacent to the selected area; and means for depositing a second dot of a predetermined size on the adjacent area, the second dot being of a size predetermined in response to the scaled error.
Claim 5
Independent Claim
88 words
An apparatus for printing a gray scale image on a surface comprising: means for depositing a first dot of a predetermined size on a selected area of the surface; means for determining an error in gray level in the selected area; means for scaling the error and assigning the scaled error to an area adjacent to the selected area; and means for depositing a second dot of a predetermined size on the adjacent area, the second dot being of a size predetermined in response to the scaled error.
Claim 6
Dependent Claim
24 words
The apparatus of claim 3, wherein the means for determining an error further comprises a means for determining an error in optical density units.
Claim 7
Dependent Claim
18 words
The apparatus of claim 3, wherein the means for determining an error further comprises an error diffusion algorithm.
Claim 8
Dependent Claim
18 words
The apparatus of claim 5, wherein the means for determining an error further comprises an error diffusion algorithm.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-07-13 | 1991-01-12 | 1991-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-13 | 1995-01-12 | 1995-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-13 | 1999-01-12 | 1999-07-14 | $7700.00 | Window Closed / Lapsed |