Patent US5296920A successfully refreshed from Google Patents.
US5296920A
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Color gradation correction method and apparatus
Assignee: Panasonic Holdings Corp
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Filing: 1992-09-16
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Granted: 1994-03-22
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Expires: 2012-09-16
Abstract
Abstract A gradation correction apparatus for processing R, G, and B input signals includes a luminance signal conversion device for obtaining the original luminance signal, which is before gamma conversion, from the input signals, a luminance gamma conversion device for gamma converting the original luminance signal to the desired gradation characteristics to obtain a gamma converted luminance signal, a correction coefficient calculation means for obtaining a ratio of the gamma converted luminance signal to the original luminance signal, a first RGB operation means for multiplying the ratio by each of the R, G, and B input signals for obtaining primary gradation-corrected R, G, and B signals; a color difference signal operation means for producing a difference between each of the R, G, and B input signals and the original luminance signal; a second RGB operation means for adding the gamma converted luminance signal to each of the difference for obtaining secondary gradation-corrected R, G, and B signals; and an RGB determination means for obtaining final gradation-corrected R, G, B signals based on the primary and secondary gradation-corrected R, G, and B signals.
Inventors
- 👤 Shigeo Sakaue
- 👤 Susumu Maruno
- 👤 Haruo Yamashita
- 👤 Yasuki Matsumoto
- 👤 Hideshi Ishihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:42
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/00795; H04N9/00; H04N9/64; H04N9/68; H04N9/69; H04N1/46; H04N1/56; H04N1/60; H04N1/6027; H04N23/00; H04N23/80; H04N23/82; H04N23/83; H04N9/77
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
137 words
A gradation correction method comprising the steps of: (a) obtaining an original luminance signal, which is before gamma conversion, from R, G, and B input signals; (b) gamma converting said original luminance signal according to a predetermined gradation characteristics for obtaining a gamma converted luminance signal; (c) multiplying a ratio of the gamma converted luminance signal to the original luminance signal by each of the R, G, and B input signals for obtaining primary gradation-corrected R, G, and B signals; (d) adding a difference between each of the R, G, and B input signals and the original luminance signal to the gamma converted luminance signal for obtaining secondary gradation-corrected R, G, and B signals; and (e) obtaining a final gradation-corrected R, G, and B signals based on said primary and secondary gradation-corrected R, G, and B signals.
Claim 2
Dependent Claim
137 words
A gradation correction method comprising the steps of: (a) obtaining an original luminance signal, which is before gamma conversion, from R, G, and B input signals; (b) gamma converting said original luminance signal according to a predetermined gradation characteristics for obtaining a gamma converted luminance signal; (c) multiplying a ratio of the gamma converted luminance signal to the original luminance signal by each of the R, G, and B input signals for obtaining primary gradation-corrected R, G, and B signals; (d) adding a difference between each of the R, G, and B input signals and the original luminance signal to the gamma converted luminance signal for obtaining secondary gradation-corrected R, G, and B signals; and (e) obtaining a final gradation-corrected R, G, and B signals based on said primary and secondary gradation-corrected R, G, and B signals.
Claim 3
Dependent Claim
44 words
A gradation correction method as claimed in claim 1, wherein said step (e) obtains the final gradation-corrected R, G, and B signals by interpolation from the primary and secondary gradation-corrected R, G, and B signals depending on the value of the original luminance signal.
Claim 4
Dependent Claim
181 words
A gradation correction apparatus for processing R, G, and B input signals, comprising: a luminance signal conversion means for obtaining the original luminance signal, which is before gamma conversion, from the input signals; a luminance gamma conversion means for gamma converting said original luminance signal to the desired gradation characteristics to obtain a gamma converted luminance signal; a correction coefficient calculation means for obtaining a ratio of the gamma converted luminance signal to the original luminance signal; a first RGB operation means for multiplying said ratio by each of the R, G, and B input signals for obtaining primary gradation-corrected R, G, and B signals; a color difference signal operation means for producing a difference between each of the R, G, and B input signals and the original luminance signal; a second RGB operation means for adding the gamma converted luminance signal to each of said difference for obtaining secondary gradation-corrected R, G, and B signals; and an RGB determination means for obtaining final gradation-corrected R, G, B signals based on said primary and secondary gradation-corrected R, G, and B signals.
Claim 5
Dependent Claim
181 words
A gradation correction apparatus for processing R, G, and B input signals, comprising: a luminance signal conversion means for obtaining the original luminance signal, which is before gamma conversion, from the input signals; a luminance gamma conversion means for gamma converting said original luminance signal to the desired gradation characteristics to obtain a gamma converted luminance signal; a correction coefficient calculation means for obtaining a ratio of the gamma converted luminance signal to the original luminance signal; a first RGB operation means for multiplying said ratio by each of the R, G, and B input signals for obtaining primary gradation-corrected R, G, and B signals; a color difference signal operation means for producing a difference between each of the R, G, and B input signals and the original luminance signal; a second RGB operation means for adding the gamma converted luminance signal to each of said difference for obtaining secondary gradation-corrected R, G, and B signals; and an RGB determination means for obtaining final gradation-corrected R, G, B signals based on said primary and secondary gradation-corrected R, G, and B signals.
Claim 6
Dependent Claim
43 words
A gradation correction apparatus according to claim 3, wherein said RGB determination means obtains the final gradation-corrected R, G, B signals by interpolation from said primary and secondary gradation-corrected R, G, and B signals depending on the value of the original luminance signal.
Claim 7
Dependent Claim
109 words
A gradation correction method comprising the steps of: (a) obtaining an original luminance signal and first and second original color difference signals; (b) gamma converting said original luminance signal according to a predetermined gradation characteristics for obtaining a gamma converted luminance signal; (c) multiplying a ratio of the gamma converted luminance signal to the original luminance signal by each of the first and second original color difference signals for obtaining first and second primary gradation-corrected color difference signals; and (d) obtaining first and second final gradation-corrected color difference signals based on said first and second primary gradation-corrected color difference signals and said first and second original color difference signals.
Claim 8
Dependent Claim
109 words
A gradation correction method comprising the steps of: (a) obtaining an original luminance signal and first and second original color difference signals; (b) gamma converting said original luminance signal according to a predetermined gradation characteristics for obtaining a gamma converted luminance signal; (c) multiplying a ratio of the gamma converted luminance signal to the original luminance signal by each of the first and second original color difference signals for obtaining first and second primary gradation-corrected color difference signals; and (d) obtaining first and second final gradation-corrected color difference signals based on said first and second primary gradation-corrected color difference signals and said first and second original color difference signals.
Claim 9
Dependent Claim
44 words
A gradation correction method as claimed in claim 5, wherein said step (d) obtains the final gradation-corrected color difference signal by interpolation from the primary gradation-corrected color difference signals and said original color difference signals depending on the value of the original luminance signal.
Claim 10
Dependent Claim
86 words
A gradation correction method comprising the steps of: (a) obtaining an original luminance signal and two-phase modulated original chroma signal; (b) gamma converting said original luminance signal according to a predetermined gradation characteristics for obtaining a gamma converted luminance signal; (c) multiplying a ratio of the gamma converted luminance signal to the original luminance signal by said original chroma signal for obtaining a primary gradation-corrected chroma signal; and (d) obtaining final gradation-corrected chroma signal based on said primary gradation-corrected chroma signal and said original chroma signal.
Claim 11
Dependent Claim
86 words
A gradation correction method comprising the steps of: (a) obtaining an original luminance signal and two-phase modulated original chroma signal; (b) gamma converting said original luminance signal according to a predetermined gradation characteristics for obtaining a gamma converted luminance signal; (c) multiplying a ratio of the gamma converted luminance signal to the original luminance signal by said original chroma signal for obtaining a primary gradation-corrected chroma signal; and (d) obtaining final gradation-corrected chroma signal based on said primary gradation-corrected chroma signal and said original chroma signal.
Claim 12
Dependent Claim
41 words
A gradation correction method as claimed in claim 7, wherein said step (d) obtains the final gradation-corrected chroma signal by interpolation from said primary gradation-corrected chroma signal and said original chroma signal depending on the value of the original luminance signal.
Claim 13
Dependent Claim
128 words
A gradation correction apparatus for processing an input luminance signal and first and second input color difference signals comprising: a luminance gamma conversion means for gamma converting said input luminance signal to the desired gradation characteristics to obtain a gamma converted luminance signal; a correction coefficient calculation means for obtaining a ratio of the gamma converted luminance signal to the input luminance signal; a color difference conversion means for multiplying each of said first and second color difference signals by said ratio for obtaining first and second primary gradation-corrected color difference signals and a color difference determination means for obtaining first and second final gradation-corrected color difference signals based on said first and second primary gradation-corrected color difference signals and said first and second input color difference signals.
Claim 14
Dependent Claim
128 words
A gradation correction apparatus for processing an input luminance signal and first and second input color difference signals comprising: a luminance gamma conversion means for gamma converting said input luminance signal to the desired gradation characteristics to obtain a gamma converted luminance signal; a correction coefficient calculation means for obtaining a ratio of the gamma converted luminance signal to the input luminance signal; a color difference conversion means for multiplying each of said first and second color difference signals by said ratio for obtaining first and second primary gradation-corrected color difference signals and a color difference determination means for obtaining first and second final gradation-corrected color difference signals based on said first and second primary gradation-corrected color difference signals and said first and second input color difference signals.
Claim 15
Dependent Claim
51 words
A gradation correction apparatus according to claim 9, wherein said color difference determination means obtains the final gradation-corrected color difference signals by interpolation from said first and second primary gradation-corrected color difference signals and said first and second input color difference signals depending on the value of the input luminance signal.
Claim 16
Dependent Claim
102 words
A gradation correction apparatus for processing an input luminance signal and an input chroma signal comprising: a luminance gamma conversion means for gamma converting said input luminance signal to the desired gradation characteristics to obtain a gamma converted luminance signal; a correction coefficient calculation means for obtaining a ratio of the gamma converted luminance signal to the input luminance signal; a chrominance conversion means for multiplying said input chroma signal with said ratio for obtaining primary gradation-corrected chroma signals; and a chrominance determination means for obtaining final gradation-corrected chroma signal based on said primary gradation-corrected chroma signal and said input chroma signal.
Claim 17
Dependent Claim
102 words
A gradation correction apparatus for processing an input luminance signal and an input chroma signal comprising: a luminance gamma conversion means for gamma converting said input luminance signal to the desired gradation characteristics to obtain a gamma converted luminance signal; a correction coefficient calculation means for obtaining a ratio of the gamma converted luminance signal to the input luminance signal; a chrominance conversion means for multiplying said input chroma signal with said ratio for obtaining primary gradation-corrected chroma signals; and a chrominance determination means for obtaining final gradation-corrected chroma signal based on said primary gradation-corrected chroma signal and said input chroma signal.
Claim 18
Dependent Claim
41 words
A gradation correction apparatus according to claim 11, wherein said chrominance determination means obtains the final gradation-corrected chroma signal by interpolation from said primary gradation-corrected chroma signal and said input chroma signal depending on the value of the input luminance signal.
References Cited (Backward Citations)
US4086615A
Cited
US4668979A
Cited
FR2575884A1
Cited
US4697208A
Cited
US4841360A
Cited
GB2194706A
Cited
US4812903A
Cited
US4831434A
Cited
JPS6367890A
Cited
JPS63275285A
Cited
JPS6441593A
Cited
JPH01154694A
Cited
US4837612A
Cited
JPH02140088A
Cited
JPH02295394A
Cited
JPH036987A
Cited
JPH0364192A
Cited
JPH0373674A
Cited
EP0430165A2
Cited
JPH0417486A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-03-21 | 1997-09-20 | 1998-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-21 | 2001-09-20 | 2002-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-21 | 2005-09-20 | 2006-03-22 | $7700.00 | Window Closed / Lapsed |