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US4967277A
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Non-linear keyer
Assignee: Grass Valley USA LLC
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Filing: 1989-10-06
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Granted: 1990-10-30
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Expires: 2009-10-06
Abstract
Abstract A non-linear keyer breaks a key processor transfer function into two pieces, one above and one below a clip level. Each piece may be modified independently and then recombined to produce the desired non-linear transfer function.
Inventors
- 👤 Daniel J. Chaplin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:16
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/222; H04N5/262; H04N5/272; H04N5/275
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
93 words
A non-linear keyer having a key source video signal and a clip signal as inputs comprising: means for separating a key transfer function into two pieces, one piece being applied to values of the key source video signal above the clip signal and the other piece being applied to values of the key source video signal below the clip signal; means for independently varying the slope of the transfer function for each piece; and means for combining the two pieces to form a desired non-linear transfer function for the key source video signal.
Claim 2
Dependent Claim
93 words
A non-linear keyer having a key source video signal and a clip signal as inputs comprising: means for separating a key transfer function into two pieces, one piece being applied to values of the key source video signal above the clip signal and the other piece being applied to values of the key source video signal below the clip signal; means for independently varying the slope of the transfer function for each piece; and means for combining the two pieces to form a desired non-linear transfer function for the key source video signal.
Claim 3
Dependent Claim
116 words
A non-linear keyer having a key source video signal and a clip signal as inputs comprising: a positive absolute value variable amplifier to which the key source video signal and the clip signal are input to independently amplify values of the key source video signal above the clip signal with a first gain value; a negative absolute value variable amplifier to which the key source video signal and the clip signal are input to independently amplify values of the key source video signal below the clip signal with a second gain value; and means for combining the outputs of the absolute value variable amplifiers to produce a non-linear transfer function for the key source video signal.
Claim 4
Dependent Claim
116 words
A non-linear keyer having a key source video signal and a clip signal as inputs comprising: a positive absolute value variable amplifier to which the key source video signal and the clip signal are input to independently amplify values of the key source video signal above the clip signal with a first gain value; a negative absolute value variable amplifier to which the key source video signal and the clip signal are input to independently amplify values of the key source video signal below the clip signal with a second gain value; and means for combining the outputs of the absolute value variable amplifiers to produce a non-linear transfer function for the key source video signal.
Claim 5
Dependent Claim
100 words
A non-linear keyer having a key source video signal and a clip signal as inputs comprising: a linear variable amplifier to which the key source video signal and the clip signal are input, the linear variable amplifier having a first gain value; a negative absolute value variable amplifier to which the key source video signal and the clip signal are input, the negative absolute value variable amplifier having a second gain value independent of the first gain value; and means for combining the outputs from the variable amplifiers to produce a non-linear transfer function for the key source video signal.
Claim 6
Dependent Claim
100 words
A non-linear keyer having a key source video signal and a clip signal as inputs comprising: a linear variable amplifier to which the key source video signal and the clip signal are input, the linear variable amplifier having a first gain value; a negative absolute value variable amplifier to which the key source video signal and the clip signal are input, the negative absolute value variable amplifier having a second gain value independent of the first gain value; and means for combining the outputs from the variable amplifiers to produce a non-linear transfer function for the key source video signal.
Claim 7
Independent Claim
77 words
A method of generating a non-linear transfer function for a key signal generator having a key source video signal and a clip signal as inputs comprising the steps of: separating a key transfer function into two pieces, one above the clip signal and the other below the clip signal; independently varying the slope of each piece of the key transfer function; and combining the two pieces of the key transfer function to produce the non-linear transfer function.
Claim 8
Independent Claim
77 words
A method of generating a non-linear transfer function for a key signal generator having a key source video signal and a clip signal as inputs comprising the steps of: separating a key transfer function into two pieces, one above the clip signal and the other below the clip signal; independently varying the slope of each piece of the key transfer function; and combining the two pieces of the key transfer function to produce the non-linear transfer function.
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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) | 1993-10-29 | 1994-04-30 | 1994-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-29 | 1998-04-30 | 1998-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-29 | 2002-04-30 | 2002-10-30 | $7700.00 | Window Closed / Lapsed |