Patent US4667224A successfully refreshed from Google Patents.
US4667224A
Expired / Lapsed
US
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White balance correcting device
Assignee: Panasonic Holdings Corp
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Filing: 1985-05-21
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Granted: 1987-05-19
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Expires: 2005-05-21
Abstract
Abstract A white balance correcting device which is constructed to reduce at a time of high luminance input the low frequency luminance signal component included in either an input low frequency luminance signal or in a color difference signal of a gain-control matrix circuit which is generating the color difference signal upon receiving a color signal and low luminance signal, so as to thereby produce a precise color balance of a video picture at the time of a high luminance input.
Inventors
- 👤 Akihito Fujisige
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:15
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/73; H04N23/00; H04N23/80; H04N23/84; H04N23/88
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
168 words
In a white balance correcting device for use in a color video camera, wherein two color signals of image signal outputs from an imaging means are supplied to first and second gain-control matrix circuits which also respectively receive low frequency components of the image signal outputs from the image means, and wherein said first and second gain control matrix circuits each output a color difference signal having a portion which is converted into a DC voltage through respective smoothing circuits, and wherein the difference between the DC voltage and a predetermined reference voltage is respectively fed back to said first and second gain-control matrix circuits, the improvement comprising: a luminance signal reducing means, disposed between one of said first and second gain-control matrix circuits and its respective smoothing circuit, for reducing a level of the low frequency luminance signal component of an input signal supplied thereto, said input signal corresponding to said color difference signal output from its respective one of said first and second gain-control matrix circuits.
Claim 2
Dependent Claim
168 words
In a white balance correcting device for use in a color video camera, wherein two color signals of image signal outputs from an imaging means are supplied to first and second gain-control matrix circuits which also respectively receive low frequency components of the image signal outputs from the image means, and wherein said first and second gain control matrix circuits each output a color difference signal having a portion which is converted into a DC voltage through respective smoothing circuits, and wherein the difference between the DC voltage and a predetermined reference voltage is respectively fed back to said first and second gain-control matrix circuits, the improvement comprising: a luminance signal reducing means, disposed between one of said first and second gain-control matrix circuits and its respective smoothing circuit, for reducing a level of the low frequency luminance signal component of an input signal supplied thereto, said input signal corresponding to said color difference signal output from its respective one of said first and second gain-control matrix circuits.
Claim 3
Dependent Claim
155 words
In a white balance correcting device for use in a color video camera, wherein two color signals of image signal outputs from an imaging means are supplied to first and second gain-control matrix circuits which also respectively receive low frequency components of the image signal outputs from the image means, and wherein said first and second gain-control matrix circuits each output a color difference signal having a portion which is converted into a DC voltage through respective smoothing circuits, and wherein the difference between the DC voltage and a predetermined reference voltage is respectively fed back to said first and second gain-control matrix circuits, the improvement comprising: a luminance signal reducing means, disposed between said imaging means and one of said first and second gain-control matrix circuits, for reducing a level of the low frequency signal component of an input signal supplied thereto, said input signal corresponding to its respective output of said imaging means.
Claim 4
Dependent Claim
155 words
In a white balance correcting device for use in a color video camera, wherein two color signals of image signal outputs from an imaging means are supplied to first and second gain-control matrix circuits which also respectively receive low frequency components of the image signal outputs from the image means, and wherein said first and second gain-control matrix circuits each output a color difference signal having a portion which is converted into a DC voltage through respective smoothing circuits, and wherein the difference between the DC voltage and a predetermined reference voltage is respectively fed back to said first and second gain-control matrix circuits, the improvement comprising: a luminance signal reducing means, disposed between said imaging means and one of said first and second gain-control matrix circuits, for reducing a level of the low frequency signal component of an input signal supplied thereto, said input signal corresponding to its respective output of said imaging means.
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) | 1990-05-18 | 1990-11-17 | 1991-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-18 | 1994-11-17 | 1995-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-18 | 1998-11-17 | 1999-05-19 | $7700.00 | Window Closed / Lapsed |