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US4503464A
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Gamma correction circuit for television
Assignee: US Philips Corp
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Filing: 1983-01-14
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Granted: 1985-03-05
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Expires: 2003-01-14
Abstract
Abstract A gamma correction circuit for television, incorporating a gamma corrector (9) having an output (10) with a gamma-corrected signal (S2), a first superposition stage (16) for supplying, relative to the linear input signal (S1) a difference signal (S3) which corresponds to the gamma correction, a second superposition stage (3) for supplying a signal (S1+S3') which is formed by the difference signal (S3), with inverted gamma relative to the linear input signal (S1) which signal (S1+S3') is applied to the gamma corrector (9). As a result thereof values which exceed the peak-white value (w) are not displayed with a picture brightness which is less than the peak-white value (w).
Inventors
- 👤 Pieter B. Dielhof
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:13
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/20; H04N5/202
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
116 words
A gamma correction circuit for a television system comprising: an input terminal connected to receive a signal for gamma correction; a gamma correction having an input and an output; a first superposition stage having a first input connected to said gamma corrector output, a second input connected to said input terminal and an output, said first stage output supplying a difference signal corresponding to the gamma correction; a second superposition stage having a first input connected to said first superposition stage output, a second input connected to said input terminal, and an output connected to supply a signal with inverted gamma to said gamma corrector input; and an output terminal connected to said gamma corrector output.
Claim 2
Dependent Claim
116 words
A gamma correction circuit for a television system comprising: an input terminal connected to receive a signal for gamma correction; a gamma correction having an input and an output; a first superposition stage having a first input connected to said gamma corrector output, a second input connected to said input terminal and an output, said first stage output supplying a difference signal corresponding to the gamma correction; a second superposition stage having a first input connected to said first superposition stage output, a second input connected to said input terminal, and an output connected to supply a signal with inverted gamma to said gamma corrector input; and an output terminal connected to said gamma corrector output.
Claim 3
Dependent Claim
14 words
A television camera provided with a gamma correction circuit as claimed in claim 1.
References Cited (Backward Citations)
US4200888A
Cited
US4227216A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-03-04 | 1988-09-03 | 1989-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-04 | 1992-09-03 | 1993-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-04 | 1996-09-03 | 1997-03-05 | $7700.00 | Window Closed / Lapsed |