US4977398A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Color to monochrome conversion
Assignee: Intel Corp
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Filing: 1989-09-18
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Granted: 1990-12-11
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Expires: 2009-09-18
Abstract
Abstract The present invention provides a contrast enhancing method and circuit for mapping color signals into signals for driving a display which is capable of displaying shades of gray. With the present invention a preliminary translation is first made between a foreground-background color combination and the various shades of gray that can be displayed. The contrast or separation between the foreground level of gray and the background level of gray produced by this preliminary translation is then compared to parameters set by the operator. If the preliminary translation provides the desired degree of separation between the foreground and the background gray levels, no further translation takes place; however, if the desired degree of separaton was not achieved by the preliminary translation, the system forces further separation between the foreground and background by taking the following action: (a) if the background was darker than the foreground, the background is made still darker and/or the foreground is made still lighter (b) if the background was lighter than the foreground the background is made still lighter and/or the foreground is made still darker.
Inventors
- 👤 Robert M. Pleva
- 👤 Martin Randall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:12
CPC Classifications
G; G09; G09G; G09G5/00; G09G5/02; G09G5/028
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
108 words
A contrast enhancing circuit for mapping color signals into signals for driving a display which is capable of displaying levels of gray comprising: means for making an initial assignment of foreground and background colors to levels of gray; means for determining if the separation between the foreground gray level and the background gray level produced by said initial assignment exceeds a predetermined separation threshold; and means for increasing said separation when said threshold is not exceeded by said separation by modifying said initially assigned levels of gray of said foreground and background colors without modifying levels of gray for alternate foreground and background colors which exceed said separation.
Claim 2
Dependent Claim
108 words
A contrast enhancing circuit for mapping color signals into signals for driving a display which is capable of displaying levels of gray comprising: means for making an initial assignment of foreground and background colors to levels of gray; means for determining if the separation between the foreground gray level and the background gray level produced by said initial assignment exceeds a predetermined separation threshold; and means for increasing said separation when said threshold is not exceeded by said separation by modifying said initially assigned levels of gray of said foreground and background colors without modifying levels of gray for alternate foreground and background colors which exceed said separation.
Claim 3
Dependent Claim
26 words
The circuit recited in claim 1 including means for increasing said separation by making the background still darker if the background is darker than the foreground.
Claim 4
Dependent Claim
34 words
The circuit of claim 2 wherein the means for making an initial assignment includes means for making the initial assignment for the background and foreground colors from a single range of possible gray levels.
Claim 5
Dependent Claim
26 words
The circuit recited in claim 1 including means for increasing said separation by making the foreground still lighter if the foreground is lighter than the background.
Claim 6
Dependent Claim
34 words
The circuit of claim 4 wherein the means for making an initial assignment includes means for making the initial assignment for the background and foreground colors from a single range of possible gray levels.
Claim 7
Dependent Claim
34 words
The circuit of claim 1 wherein the means for making an initial assignment includes means for making the initial assignment for the background and foreground colors from a single range of possible gray levels.
Claim 8
Dependent Claim
101 words
A contrast enhancing method for mapping color signals into signals for driving a display which is capable of displaying levels of gray comprising the steps of: making an initial assignment of foreground and background colors to levels of gray; determining if the separation between the foreground level of gray and the background level of gray produced by said initial assignment exceeds a predetermined separation threshold; and increasing said separation when said threshold is not exceeded by said separation by modifying said initially assigned values without modifying values for levels of gray for alternate foreground and background colors which exceed said separation.
Claim 9
Dependent Claim
101 words
A contrast enhancing method for mapping color signals into signals for driving a display which is capable of displaying levels of gray comprising the steps of: making an initial assignment of foreground and background colors to levels of gray; determining if the separation between the foreground level of gray and the background level of gray produced by said initial assignment exceeds a predetermined separation threshold; and increasing said separation when said threshold is not exceeded by said separation by modifying said initially assigned values without modifying values for levels of gray for alternate foreground and background colors which exceed said separation.
Claim 10
Dependent Claim
25 words
The method recited in claim 7 where said separation is increased by making the background still darker if the background is darker than the foreground.
Claim 11
Dependent Claim
38 words
The method of claim 8 wherein the step of making an initial assignment further includes the step of assigning the levels of gray to the foreground and to the background from a single range of gray scale levels.
Claim 12
Dependent Claim
24 words
The method of claim 7 where said separation is increased by making the foreground still lighter if the foreground is lighter than the background.
Claim 13
Dependent Claim
38 words
The method of claim 10 wherein the step of making an initial assignment further includes the step of assigning the levels of gray to the foreground and to the background from a single range of gray scale levels.
Claim 14
Dependent Claim
38 words
The method of claim 7 wherein the step of making an initial assignment further includes the step of assigning the levels of gray to the foreground and to the background from a single range of gray scale levels.
Claim 15
Independent Claim
160 words
A system for translating a plurality of color signals into a plurality of signals for driving a display which is capable of displaying shades of gray, comprising: means for making an initial assignment of numeric values to said color signals, said numeric values designating preselected shades of gray and a particular numeric value representative of a particular gray scale level; means for testing a contrast between a gray scale level combination produced by said initial assignment to determine if said contrast meets a prespecified criteria; and means, operative if said contrast does not meet said prespecified criteria, for arithmetically operating on said numeric values of said initial assignment in order to enhance said contrast, said arithmetically operating means further including means for operating on only a gray scale level of said gray scale level combination to be displayed which does not meet said prespecified criteria, without altering any values for alternate gray scale level combinations which meet said prespecified criteria.
Claim 16
Independent Claim
160 words
A system for translating a plurality of color signals into a plurality of signals for driving a display which is capable of displaying shades of gray, comprising: means for making an initial assignment of numeric values to said color signals, said numeric values designating preselected shades of gray and a particular numeric value representative of a particular gray scale level; means for testing a contrast between a gray scale level combination produced by said initial assignment to determine if said contrast meets a prespecified criteria; and means, operative if said contrast does not meet said prespecified criteria, for arithmetically operating on said numeric values of said initial assignment in order to enhance said contrast, said arithmetically operating means further including means for operating on only a gray scale level of said gray scale level combination to be displayed which does not meet said prespecified criteria, without altering any values for alternate gray scale level combinations which meet said prespecified criteria.
Claim 17
Dependent Claim
154 words
A contrast enhancing method for translating a plurality of color signals into a plurality of signals for driving a display which is capable of displaying shades of gray, comprising the steps of: making an initial assignment of numeric values to said color signals, said numeric values designating preselected shades of gray and a particular numeric value representative of a particular gray scale level; testing a contrast between a gray scale level combination produced by said initial assignment to determine if said contrast meets a prespecified criteria; and operating arithmetically on said initial assignment if said contrast does not meet said prespecified criteria, in order to enhance said contrast, said operating step further including the step of operating on only a gray scale level of said gray scale level combination to be displayed which does not meet said prespecified criteria, without altering any values for alternate gray scale level combinations which meet said prespecified criteria.
Claim 18
Dependent Claim
154 words
A contrast enhancing method for translating a plurality of color signals into a plurality of signals for driving a display which is capable of displaying shades of gray, comprising the steps of: making an initial assignment of numeric values to said color signals, said numeric values designating preselected shades of gray and a particular numeric value representative of a particular gray scale level; testing a contrast between a gray scale level combination produced by said initial assignment to determine if said contrast meets a prespecified criteria; and operating arithmetically on said initial assignment if said contrast does not meet said prespecified criteria, in order to enhance said contrast, said operating step further including the step of operating on only a gray scale level of said gray scale level combination to be displayed which does not meet said prespecified criteria, without altering any values for alternate gray scale level combinations which meet said prespecified criteria.
References Cited (Backward Citations)
US4236175A
Cited
US4382254A
Cited
US4481529A
Cited
US4688031A
Cited
US4703318A
Cited
US4755954A
Cited
US4727414A
Cited
US4725833A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-10 | 1994-06-11 | 1994-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-10 | 1998-06-11 | 1998-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-10 | 2002-06-11 | 2002-12-11 | $7700.00 | Window Closed / Lapsed |