US4920415A
Expired / Lapsed
US
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Self keyer
Assignee: Grass Valley USA LLC
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Filing: 1989-03-20
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Granted: 1990-04-24
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Expires: 2009-03-20
Abstract
Abstract An improved self keyer preconditions a fill video prior to mixing with a background video under control of a self key signal derived from the fill video. A variable gray luminance signal is substituted for low luminance portions of the fill video under control of a precondition key signal derived from the self key signal to produce the preconditioned fill video. The resulting output video has a smooth luminance transition between the fill and background videos in lieu of an unpleasant black artifact at the edges of the fill video.
Inventors
- 👤 Daniel J. Chaplin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:57
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/222; H04N5/262; H04N5/2622
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
72 words
An improved self keyer of the type having means for deriving a self key signal from a fill video and means for mixing the fill video with a background video under control of the self key signal to produce an output video, the improvement comprising means for preconditioning the fill video prior to input to the mixing means by replacing low luminance portions of the fill video with a variable transition signal.
Claim 2
Dependent Claim
72 words
An improved self keyer of the type having means for deriving a self key signal from a fill video and means for mixing the fill video with a background video under control of the self key signal to produce an output video, the improvement comprising means for preconditioning the fill video prior to input to the mixing means by replacing low luminance portions of the fill video with a variable transition signal.
Claim 3
Dependent Claim
50 words
An improved self keyer as recited in claim 1 wherein the preconditioning means comprises: means for deriving a second key signal from the self key signal; and means for mixing the fill video with the transition signal under control of the second key signal to produce the preconditioned fill video.
Claim 4
Dependent Claim
49 words
An improved self keyer as recited in claim 1 wherein the preconditioning means comprises: means for deriving a second key signal from the fill video; and means for mixing the fill video with the transition signal under control of the second key signal to produce the preconditioned fill video.
Claim 5
Dependent Claim
59 words
A self keyer comprising: means for combining a fill video with a background video under control of a self key signal derived from the fill video to produce an output video; and means for preconditioning the fill video prior to input to the combining means by replacing low luminance portions of the fill video with a variable transition signal.
Claim 6
Dependent Claim
59 words
A self keyer comprising: means for combining a fill video with a background video under control of a self key signal derived from the fill video to produce an output video; and means for preconditioning the fill video prior to input to the combining means by replacing low luminance portions of the fill video with a variable transition signal.
Claim 7
Dependent Claim
48 words
A self keyer as recited in claim 4 wherein the combining means comprises: means for deriving the self key signal from the fill video; and means for mixing the preconditioned fill video with the background video under control of the self key signal to produce the output signal.
Claim 8
Dependent Claim
49 words
A self keyer as recited in claim 4 wherein the preconditioning means comprises: means for deriving a second key signal from the self key signal; and means for mixing the fill video with the transition signal under control of the second key signal to produce the preconditioned fill video.
Claim 9
Dependent Claim
48 words
A self keyer as recited in claim 4 wherein the preconditioning means comprises: means for deriving a second key signal from the fill video; and means for mixing the fill video with the transition signal under control of the second key signal to produce the preconditioned fill video.
Claim 10
Independent Claim
68 words
A method of generating an output video that is a combination of a fill video and a background video comprising the steps of: preconditioning the fill video to replace low luminance portions of the fill video with a variable luminance gray signal; and mixing the preconditioned fill video with the background video under control of a key signal derived from the fill video to produce the output video.
Claim 11
Independent Claim
68 words
A method of generating an output video that is a combination of a fill video and a background video comprising the steps of: preconditioning the fill video to replace low luminance portions of the fill video with a variable luminance gray signal; and mixing the preconditioned fill video with the background video under control of a key signal derived from the fill video to produce the output video.
Claim 12
Dependent Claim
46 words
A method as recited in claim 8 wherein the mixing step comprises the steps of: deriving the self key signal from the fill video; and mixing the preconditioned fill video with the background video under control of the self key signal to produce the output signal.
Claim 13
Dependent Claim
47 words
A method as recited in claim 8 wherein the preconditioning step comprises the steps of: deriving a second key signal from the self key signal; and mixing the fill video with the transition signal under control of the second key signal to produce the preconditioned fill video.
Claim 14
Dependent Claim
46 words
A method as recited in claim 8 wherein the preconditioning step comprises the steps of: deriving a second key signal from the fill video; and mixing the fill video with the transition signal under control of the second key signal to produce the preconditioned fill video.
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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) | 1993-04-23 | 1993-10-23 | 1994-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-23 | 1997-10-23 | 1998-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-23 | 2001-10-23 | 2002-04-24 | $7700.00 | Window Closed / Lapsed |