US3684825A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Contrast compression circuits
Assignee: RCA Corp
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Filing: 1971-02-19
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Granted: 1972-08-15
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Expires: 1991-02-19
Abstract
Abstract Apparatus for a television camera is described wherein the highest peak intensity of one of the primary colors is processed to form a multiplying control signal. The control signal is used to compensate a video signal in order to obtain a reduced range of contrast values capable of being adequately displayed by the system.
Inventors
- 👤 Robert Adams Dischert
- 👤 John Francis Monahan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:39
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/80; H04N23/82; H04N23/83
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
194 words
Apparatus for use in a color television system including means for deriving video signals from a scene, said signals being representative of the color content of said scene, comprising: a. a plurality of signal source means producing at their respective outputs color information electrical signals respectively responsive to the intensity of different colors of light reflected by said scene, b. control signal generation means responsive to said electrical signals to provide a control signal principally responsive to each of said color information electrical signals so long as it is not smaller than one of the others, said control signal thereby being indicative of the maximum intensity of any of said different primary colors, and c. signal processing means having a plurality of input terminals coupled respectively to the outputs of said signal source means and another input terminal coupled to receive said control signal, said signal processing means including a multiplier for multiplying signal information as obtained from each of said color information electrical signals by the same factor and in proportion to said control signal to provide modified signal information having a reduced contrast range with respect to said color information electrical signals.
Claim 2
Dependent Claim
194 words
Apparatus for use in a color television system including means for deriving video signals from a scene, said signals being representative of the color content of said scene, comprising: a. a plurality of signal source means producing at their respective outputs color information electrical signals respectively responsive to the intensity of different colors of light reflected by said scene, b. control signal generation means responsive to said electrical signals to provide a control signal principally responsive to each of said color information electrical signals so long as it is not smaller than one of the others, said control signal thereby being indicative of the maximum intensity of any of said different primary colors, and c. signal processing means having a plurality of input terminals coupled respectively to the outputs of said signal source means and another input terminal coupled to receive said control signal, said signal processing means including a multiplier for multiplying signal information as obtained from each of said color information electrical signals by the same factor and in proportion to said control signal to provide modified signal information having a reduced contrast range with respect to said color information electrical signals.
Claim 3
Independent Claim
209 words
An apparatus foR producing a composite video information signal containing a plurality of color information signals and a luminance information signal representative of the brightness of a desired scene, comprising: a. means to provide said color information signals, each of said color information signals respectively determined by the intensity of a different predetermined primary color reflected by said scene, b. signal combining means having inputs coupled to receive respective ones of said color information signals and an output from which a first composite video signal is provided in response to predetermined proportioned amounts of said color information signals, c. control signal generation means coupled to receive said color information signals to detect the largest of the same to provide a control signal indicative of the maximum light intensity associated with each color information signal as reflected by said scene, d. multiplier means having a first input to which said first composite video signal is coupled, having a second input to which said control signal is coupled, and an output for providing a second composite video signal which is the product of said first composite video signal and said control signal, whereby said second composite video signal is compressed in contrast range with respect to said first composite video signal.
Claim 4
Independent Claim
209 words
An apparatus foR producing a composite video information signal containing a plurality of color information signals and a luminance information signal representative of the brightness of a desired scene, comprising: a. means to provide said color information signals, each of said color information signals respectively determined by the intensity of a different predetermined primary color reflected by said scene, b. signal combining means having inputs coupled to receive respective ones of said color information signals and an output from which a first composite video signal is provided in response to predetermined proportioned amounts of said color information signals, c. control signal generation means coupled to receive said color information signals to detect the largest of the same to provide a control signal indicative of the maximum light intensity associated with each color information signal as reflected by said scene, d. multiplier means having a first input to which said first composite video signal is coupled, having a second input to which said control signal is coupled, and an output for providing a second composite video signal which is the product of said first composite video signal and said control signal, whereby said second composite video signal is compressed in contrast range with respect to said first composite video signal.
Claim 5
Dependent Claim
193 words
Apparatus for reducing the contrast range of a televised scene by providing a composite video information signal representative of said scene and generated by a plurality of color information signals determined by the intensity of colors reflected by said scene, comprising: a. means to provide said plurality of color information signals which have predetermined phase and amplitude characteristics with respect to each other: b. first means responsive to said color information signals for detecting the largest of the same to provide a control signal indicative of the peak intensity of the most intense of said colors reflected by said scene, c. second means coupled to said first means for processing said control signal according to a predetermined relationship selected in accordance with a desired contrast range to provide a processed control signal d. means coupled to said second means and responsive to said color information signals to multiply said signals by said processed control signal to provide multiplied color information signals in which the proper proportions between said predetermined characteristics as existing prior to said multiplication are maintained, and in which the contrast range is reduced with respect to said color information signals.
Claim 6
Dependent Claim
193 words
Apparatus for reducing the contrast range of a televised scene by providing a composite video information signal representative of said scene and generated by a plurality of color information signals determined by the intensity of colors reflected by said scene, comprising: a. means to provide said plurality of color information signals which have predetermined phase and amplitude characteristics with respect to each other: b. first means responsive to said color information signals for detecting the largest of the same to provide a control signal indicative of the peak intensity of the most intense of said colors reflected by said scene, c. second means coupled to said first means for processing said control signal according to a predetermined relationship selected in accordance with a desired contrast range to provide a processed control signal d. means coupled to said second means and responsive to said color information signals to multiply said signals by said processed control signal to provide multiplied color information signals in which the proper proportions between said predetermined characteristics as existing prior to said multiplication are maintained, and in which the contrast range is reduced with respect to said color information signals.
Claim 7
Dependent Claim
25 words
The apparatus according to claim 2 wherein said color information signals are those representative of the red, blue and green content of the televised scene.
Claim 8
Dependent Claim
41 words
The apparatus according to claim 2 wherein said predetermined relationship is approximately equal to: Em( p l) where: Em luminance value of composite video signal for a white scene. gamma p ''''picture gamma'''' equals a decimal number between 0 and 1.
Claim 9
Dependent Claim
203 words
Apparatus for reducing the contrast range of a televised scene by providing at an output composite video information signal representative of said scene and generated by color information signals determined by the intensity of primary colors reflected by said scene, said color information signals having predetermined phase and amplitude characteristics proportioned in accordance with a luminance signal representative of the brightness of said scene, comprising: a. a plurality of multiplier circuits, each having first and second input terminal and an output terminal, said first input terminals adapted to receive a different one of said color information signals, b. first means coupled to each of said output terminals of said multiplier circuits for detecting the largest of the signals provided at each said output terminal and therefore pRoviding a control signal indicative of the most intense of said primary colors, c. second means responsive to said control signal and having an output terminal coupled to each of said second terminals of said multipliers to cause said multipliers to provide at said outputs other color information signals each multiplied by the same factor while maintaining said characteristics between said signals at the same proportions with respect to one another as existing prior to said multiplication.
Claim 10
Dependent Claim
203 words
Apparatus for reducing the contrast range of a televised scene by providing at an output composite video information signal representative of said scene and generated by color information signals determined by the intensity of primary colors reflected by said scene, said color information signals having predetermined phase and amplitude characteristics proportioned in accordance with a luminance signal representative of the brightness of said scene, comprising: a. a plurality of multiplier circuits, each having first and second input terminal and an output terminal, said first input terminals adapted to receive a different one of said color information signals, b. first means coupled to each of said output terminals of said multiplier circuits for detecting the largest of the signals provided at each said output terminal and therefore pRoviding a control signal indicative of the most intense of said primary colors, c. second means responsive to said control signal and having an output terminal coupled to each of said second terminals of said multipliers to cause said multipliers to provide at said outputs other color information signals each multiplied by the same factor while maintaining said characteristics between said signals at the same proportions with respect to one another as existing prior to said multiplication.
Claim 11
Dependent Claim
35 words
The apparatus according to claim 6 wherein said second means serves to provide a control signal according to the following relationship: (a - bEo) where: a a constant b a constant Eo output of multiplier.
Claim 12
Dependent Claim
18 words
The apparatus according to claim 6 wherein said color information signals are representative of red, green and blue.
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) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |