US3786177A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for automatic color balancing of television camera signals
Assignee: RCA Corp
•
Filing: 1972-06-19
•
Granted: 1974-01-15
•
Expires: 1992-06-19
Abstract
Abstract First, second and third signal level comparators are used to compare against a predetermined signal level respective ones of the red, green and blue color signals generated by a television camera. The outputs of the comparators are combined in an AND gate to ascertain when an essentially black or essentially white signal obtains. When such signal is present, the differences between red and green color signals and between blue and green color signals are reduced by servomechanisms.
Inventors
- 👤 L Bazin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 03:22
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/80; H04N23/84; H04N23/88
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
443 words
Apparatus applicable for use in automatic color balancing of first, second and third color signals, comprising: first, second and third input terminals adapted for application of said first, said second and said third color signals; first, second and third signal level comparator means, each having an input circuit and each having an output circuit, to provide an indication of when the excursion of input signal applied to its said input circuit exceeds a first predetermined signal level in a predetermined direction of excursion; first, second and third coupling means respectively connecting said input circuits of said first, said second and said third signal level comparator means to respective separate ones of said first, said second and said third input terminals; first combining means having input circuits coupled respectively to each of said first, said second and said third comparator means output circuits and having an output circuit at which is provided an indication of when all of said first, said second and said third comparator means provide their said indications; means to provide a first control signal responsive to the difference in amplitude between said first and said third signal level comparator input signals during the most recent such time as said first combining means provides or is provided its said indication, means to provide a second control signal responsive to the difference in amplitude between said second and said third signal level comparator input signals during the most recent such time as said first combining means provides or is provided its said indication, whereby said first and said second control signals indicate adjustments to be made to said first and to said second signal level comparator input signals, respectively, relative to said third signal level comparator input signal for color balancing to obtain, and wherein: first and second black-level control means each provides at its output circuit an output signal similar in waveform signal applied to its input circuit but with black level adjusted in accordance with a respective separate one of said first and said second control signals, said first and said second blacklevel control means being included in said first and said second coupling means, the input circuits of said first and said second black-level control means being coupled respectively to said first and to said second input terminals; fourth and fifth coupling means connecting said output circuits of said first and said second black-level control means to said input circuits of said first and said second signal level comparator means, respectively, and said first, said second and said third signal level comparators each provides its indication when its input signal swings past said first predetermined signal level towards black.
Claim 2
Dependent Claim
443 words
Apparatus applicable for use in automatic color balancing of first, second and third color signals, comprising: first, second and third input terminals adapted for application of said first, said second and said third color signals; first, second and third signal level comparator means, each having an input circuit and each having an output circuit, to provide an indication of when the excursion of input signal applied to its said input circuit exceeds a first predetermined signal level in a predetermined direction of excursion; first, second and third coupling means respectively connecting said input circuits of said first, said second and said third signal level comparator means to respective separate ones of said first, said second and said third input terminals; first combining means having input circuits coupled respectively to each of said first, said second and said third comparator means output circuits and having an output circuit at which is provided an indication of when all of said first, said second and said third comparator means provide their said indications; means to provide a first control signal responsive to the difference in amplitude between said first and said third signal level comparator input signals during the most recent such time as said first combining means provides or is provided its said indication, means to provide a second control signal responsive to the difference in amplitude between said second and said third signal level comparator input signals during the most recent such time as said first combining means provides or is provided its said indication, whereby said first and said second control signals indicate adjustments to be made to said first and to said second signal level comparator input signals, respectively, relative to said third signal level comparator input signal for color balancing to obtain, and wherein: first and second black-level control means each provides at its output circuit an output signal similar in waveform signal applied to its input circuit but with black level adjusted in accordance with a respective separate one of said first and said second control signals, said first and said second blacklevel control means being included in said first and said second coupling means, the input circuits of said first and said second black-level control means being coupled respectively to said first and to said second input terminals; fourth and fifth coupling means connecting said output circuits of said first and said second black-level control means to said input circuits of said first and said second signal level comparator means, respectively, and said first, said second and said third signal level comparators each provides its indication when its input signal swings past said first predetermined signal level towards black.
Claim 3
Dependent Claim
34 words
Apparatus applicable for use in automatic color balancing as claimed in claim 1 wherein: first, second and third gamma correction means are included in said third, said fourth and said fifth coupling means, respectively.
Claim 4
Dependent Claim
314 words
Apparatus applicable for use in automatic color balancing as claimed in claim 1 having: a first controlled gain amplifier being included in said first coupling means between said first input terminal and said input circuit of said first black-level control means and providing gain responsive to a third control signal, a second controlled gain amplifier being included in said second coupling means between said second input terminal and said input circuit of said second black-level control circuitry and providing gain responsive to a fourth control signal, fourth, fifth and sixth level comparator means each comparing an input signal applied to its input circuit with a second predetermined signal level which is towards white from said first predetermined signal level and providing at its output circuit an indication of when the excursion of its said input signal swings past said second predetermined signal level towards white, means coupling said input circuits of said fourth, said fifth and said sixth signal level comparator means to said output circuit of said first black-level control means, said output circuit of said second black-level control means and said third terminal, respectively; second combining means having input circuits coupled respectively to each of said fourth, said fifth and said sixth comparator means output circuits and providing at its output circuit an indication of when all of said fourth, said fifth and said sixth comparator means provide their said indications; means to provide said third control signal responsive to the difference in amplitude between said fourth and said sixth signal level comparator input signals during the most recent time as said second combining means provides or provided its said indication and, means to provide said fourth control signal responsive to the difference in amplitude between said fifth and said sixth signal level comparator input signals during the most recent time as said second combining means provides or provided its said indication.
Claim 5
Dependent Claim
365 words
Apparatus applicable for use in automatic color balancing of first, second and third color signals, comprising: first, second and third input terminals adapted for application of said first, said second and said third color signals; first, second and third signal level comparator means, each having an input circuit and each having an output circuit, to provide an indication of when the excursion of input signal applied to its said input circuit exceeds a first predetermined signal level in a predetermined direction of excursion; first, second and third coupling means respectively connecting said input circuits of said first, said second and said third signal level comparator means to respective separate ones of said first, said second and said third input terminals; first combining means having input circuits coupled respectively to each of said first, said second and said third comparator means output circuits and having an output circuit at which is provided an indication of when all of said first, said second and said third comparator means provide their said indications; means to provide a first control signal responsive to the difference in amplitude between said first and said third signal level comparator input signals during the most recent such time as said first combining means provides or is provided its said indication, means to provide a second control signal responsive to the difference in amplitude between said second and said third signal level comparator input signals during the most recent such time as said first combining means provides or is provided its said indication, whereby said first and said second control signals indicate adjustments to be made to said first and to said second signal level comparator input signals, respectively, relative to said third signal level comparator input signal for color balancing to obtain, and having, a source of black pedestal signal, a first black-level control circuit included in said first coupling means and adding to color signals processed therethrough said black pedestal signal in an amount responsive to said first control signal, and a second black-level control circuit included in said second coupling means, and adding to color signals processed therethrough said black pedestal signal in an amount responsive to said second control signal.
Claim 6
Dependent Claim
365 words
Apparatus applicable for use in automatic color balancing of first, second and third color signals, comprising: first, second and third input terminals adapted for application of said first, said second and said third color signals; first, second and third signal level comparator means, each having an input circuit and each having an output circuit, to provide an indication of when the excursion of input signal applied to its said input circuit exceeds a first predetermined signal level in a predetermined direction of excursion; first, second and third coupling means respectively connecting said input circuits of said first, said second and said third signal level comparator means to respective separate ones of said first, said second and said third input terminals; first combining means having input circuits coupled respectively to each of said first, said second and said third comparator means output circuits and having an output circuit at which is provided an indication of when all of said first, said second and said third comparator means provide their said indications; means to provide a first control signal responsive to the difference in amplitude between said first and said third signal level comparator input signals during the most recent such time as said first combining means provides or is provided its said indication, means to provide a second control signal responsive to the difference in amplitude between said second and said third signal level comparator input signals during the most recent such time as said first combining means provides or is provided its said indication, whereby said first and said second control signals indicate adjustments to be made to said first and to said second signal level comparator input signals, respectively, relative to said third signal level comparator input signal for color balancing to obtain, and having, a source of black pedestal signal, a first black-level control circuit included in said first coupling means and adding to color signals processed therethrough said black pedestal signal in an amount responsive to said first control signal, and a second black-level control circuit included in said second coupling means, and adding to color signals processed therethrough said black pedestal signal in an amount responsive to said second control signal.
Claim 7
Dependent Claim
123 words
Apparatus applicable for use in automatic color balancing as claimed in claim 2 wherein each of said means to provide a control signal comprises: a differential amplifier having an output circuit and having first and second input circuits coupled to separate ones of said signal level comparator input signals, a memory having an output circuit from which its said control signal is provided in response to stored information, and an input circuit for application of information to be stored and, a video gate coupling said differential amplifier output circuit to said memory inpuT circuit whenever and only whenever said first combining means provides its said indication of when all of said first, said second and said third comparator means provide their said indications.
Claim 8
Dependent Claim
444 words
Apparatus applicable for use in automatic color balancing of a plurality of number N color signals comprising: a plurality of number N input terminals, each adapted for application of a respective one of said plurality of color signals; a plurality of number N signal level comparator means, each having an input circuit and each having an output circuit, to provide an indication of when the excursion of its input signal exceeds a predetermined signal level in a predetermined direction of excursion; a plurality of number N coupling means coupling said input terminals to respective separate ones of said input circuits of said signal level comparator means; combining means having a plurality of number N input circuits coupled respectively to separate ones of said output circuits of said plurality of signal level comparator means and having an output circuit at which is provided an indication of when all of said signal level comparator means thereto coupled provide their respective said indications; a plurality of number (N-1) means to provide difference signals each having an output circuit responsive to the difference in amplitude between signal applied to a respective separate one of said input terminals except the last and signal applied to said last input terminal; a plurality of number (N-1) signal gates each having an input circuit coupled to a respective one of said output circuits of said means to provide difference signals, each having a control circuit coupled to said output circuit of said combining means and each having an output circuit providing an output signal responsive to signals at its said input circuit when its said control circuit is provided said indication from said combining means; and a plurality of number N output terminals, all but the last being coupled from respective separate ones of said output circuits of said signal gates and said last output terminal being coupled from said last input terminal, and including: a plurality of number (N-1) memories each having an output circuit from which a control signal is provided in response to stored information and each having an input circuit for application of information to be stored coupled to a respective one of said output circuits of said signal gates and, a plurality of number (N-1) black-level correction circuits being included in respective ones of said plurality of coupling means except the last, having input circuits coupled to respective ones of said input terminals except said last, having output circuits coupled to respective ones of said input circuits of said signal level comparator means and having circuits to accept control signals to determine black-level correction as supplied respectively from separate ones of said output circuits of said memories.
Claim 9
Dependent Claim
444 words
Apparatus applicable for use in automatic color balancing of a plurality of number N color signals comprising: a plurality of number N input terminals, each adapted for application of a respective one of said plurality of color signals; a plurality of number N signal level comparator means, each having an input circuit and each having an output circuit, to provide an indication of when the excursion of its input signal exceeds a predetermined signal level in a predetermined direction of excursion; a plurality of number N coupling means coupling said input terminals to respective separate ones of said input circuits of said signal level comparator means; combining means having a plurality of number N input circuits coupled respectively to separate ones of said output circuits of said plurality of signal level comparator means and having an output circuit at which is provided an indication of when all of said signal level comparator means thereto coupled provide their respective said indications; a plurality of number (N-1) means to provide difference signals each having an output circuit responsive to the difference in amplitude between signal applied to a respective separate one of said input terminals except the last and signal applied to said last input terminal; a plurality of number (N-1) signal gates each having an input circuit coupled to a respective one of said output circuits of said means to provide difference signals, each having a control circuit coupled to said output circuit of said combining means and each having an output circuit providing an output signal responsive to signals at its said input circuit when its said control circuit is provided said indication from said combining means; and a plurality of number N output terminals, all but the last being coupled from respective separate ones of said output circuits of said signal gates and said last output terminal being coupled from said last input terminal, and including: a plurality of number (N-1) memories each having an output circuit from which a control signal is provided in response to stored information and each having an input circuit for application of information to be stored coupled to a respective one of said output circuits of said signal gates and, a plurality of number (N-1) black-level correction circuits being included in respective ones of said plurality of coupling means except the last, having input circuits coupled to respective ones of said input terminals except said last, having output circuits coupled to respective ones of said input circuits of said signal level comparator means and having circuits to accept control signals to determine black-level correction as supplied respectively from separate ones of said output circuits of said memories.
Claim 10
Dependent Claim
72 words
Apparatus applicable for use in automatic color balancing of a plurality of color signals as claimed in claim 6 including, a plurality of number (N-1) controllable gain amplifiers also being included in respective ones of said plurality of coupling means except the last in cascade connection with said black-level correction circuits and being provided with respective signals to control their gains from respective separate ones of said output circuits of said memories.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |