US3743766A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Colour television camera equipments
Assignee: BAE Systems Electronics Ltd
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Filing: 1971-08-20
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Granted: 1973-07-03
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Expires: 1991-08-20
Abstract
Abstract A colour television camera equipment having vertical aperture correction in which both the vertical and horizontal components of the video signal are combed. Complementary low and high pass filters are used in the vertical and horizontal combing paths respectively. Thus vertical combing is performed to provide maximum signal output at odd multiples of half the line frequency below the highest frequency useful for vertical video information, and horizontal combing is performed to provide maximum signal output at integral multiples of the line frequency above the highest frequency useful for vertical video information.
Inventors
- 👤 P Loose
- 👤 R Sharman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:08
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/20; H04N5/205; H04N5/208; H04N25/00; H04N25/10
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
204 words
A colour television camera circuit for improving picture quality comprising, a camera tube operative to produce an output video signal, first comb filter means arranged to produce from said output video signal a combed output signal having an amplitude-frequency characteristic with amplitude maxima at odd multiples of half the line frequency and adding means for adding the output from said first comb filter means to an uncombed video signal derived from said output video signal, to correct for loss of definition due to the finite vertical dimension of the scanning spot in the camera tube, first bandpass filter means for removing from each of the signals, added in said adding means, frequencies which do not contribute to vertical definition, the circuit further comprising second comb filter means for producing from an uncombed video signal, a combed output signal, with an amplitude-frequency characteristic exhibiting amplitude maxima at integral multiples of the line frequency, second bandpass filter means for removing from the output of said second comb filter means frequencies which would adversely affect the enhancing of vertical definition achieved by said first comb filter means and means for adding the output from said second bandpass filter means to the signals added in said adding means.
Claim 2
Dependent Claim
204 words
A colour television camera circuit for improving picture quality comprising, a camera tube operative to produce an output video signal, first comb filter means arranged to produce from said output video signal a combed output signal having an amplitude-frequency characteristic with amplitude maxima at odd multiples of half the line frequency and adding means for adding the output from said first comb filter means to an uncombed video signal derived from said output video signal, to correct for loss of definition due to the finite vertical dimension of the scanning spot in the camera tube, first bandpass filter means for removing from each of the signals, added in said adding means, frequencies which do not contribute to vertical definition, the circuit further comprising second comb filter means for producing from an uncombed video signal, a combed output signal, with an amplitude-frequency characteristic exhibiting amplitude maxima at integral multiples of the line frequency, second bandpass filter means for removing from the output of said second comb filter means frequencies which would adversely affect the enhancing of vertical definition achieved by said first comb filter means and means for adding the output from said second bandpass filter means to the signals added in said adding means.
Claim 3
Dependent Claim
40 words
A circuit as claimed in claim 1 in which said second bandpass filter means has a frequency bandwidth the lower limit of which is approximately equal to the upper limit of the frequency bandwidth of said first bandpass filter means.
Claim 4
Dependent Claim
85 words
A circuit as claimed in claim 1 in which said second comb filter means comprises first delay means for delaying said output video signal by one scanning line period, second delay means for delaying the output of said first delay means by a further scanning line period and adding means for adding said output video signal to the output of said first delay means and the output of said second delay means, said first and second delay means being common to said first comb filter.
Claim 5
Dependent Claim
196 words
A colour television circuit comprising means for delaying video signal inpuT derived from a selected camera tube in the equipment by two successive delays each of one line period; a first adder connected to add said input, undelayed, to said input delayed by two line periods; a second adder connected to add said input, undelayed, to said input delayed by one line period; a first low pass filter adapted to pass frequencies below that of approximately the highest video frequency useful for vertical definition and fed with said input delayed by one line period; a second low pass filter having approximately the same pass range as the first and fed from the first adder; a high pass filter adapted to pass frequencies above approximately said highest video frequency and fed from the second adder; a third adder connected to add output from the first low pass filter to output from the second after polarity inversion of the same; means for adding the outputs from said first low pass filter, said third adder, and the high pass filter, and means for adjusting the magnitude of the input to the last mentioned adding means from said third adder.
Claim 6
Dependent Claim
196 words
A colour television circuit comprising means for delaying video signal inpuT derived from a selected camera tube in the equipment by two successive delays each of one line period; a first adder connected to add said input, undelayed, to said input delayed by two line periods; a second adder connected to add said input, undelayed, to said input delayed by one line period; a first low pass filter adapted to pass frequencies below that of approximately the highest video frequency useful for vertical definition and fed with said input delayed by one line period; a second low pass filter having approximately the same pass range as the first and fed from the first adder; a high pass filter adapted to pass frequencies above approximately said highest video frequency and fed from the second adder; a third adder connected to add output from the first low pass filter to output from the second after polarity inversion of the same; means for adding the outputs from said first low pass filter, said third adder, and the high pass filter, and means for adjusting the magnitude of the input to the last mentioned adding means from said third adder.
Claim 7
Dependent Claim
25 words
A colour television circuit as claimed in claim 4 and wherein the first low pass filter and the high pass filter have complementrary attenuation characteristics.
Claim 8
Dependent Claim
41 words
A color television circuit as claimed in claim 4 and wherein the uncorrected video signal input employed in carrying out this invention is the output from that one of the tubes in the camera which contributes most to the luminance signals.
Claim 9
Dependent Claim
31 words
A color television circuit as claimed in claim 6 and comprising a four-tube camera with a separate luminance tube and wherein said last mentioned output is that from said luminance tube.
Claim 10
Dependent Claim
34 words
A color television circuit as claimed in claim 6 and comprising a three-tube camera with red, blue and green colour tubes and wherein said last mentioned output is that from said green colour tube.
Claim 11
Dependent Claim
146 words
In a colour television camera system having a video signal output of selected bandwidth, a circuit for correcting for the vertical component of aperture distortion, said circuit comprising in combination: first comb filter means connected to said video output signal for producing a vertically combed output signal having amplitude/frequency characteristic with amplitude maxima at odd multiples of half the line frequency, said first comb filter means including filter means for removing frequencies in the higher frequency range of said bandwidth; second comb filter means connected to said video output signal for producing a horizontally combed output signal having amplitude/frequency characteristic with maxima at integral multiples of the line frequency, said second comb filter means including filter means for removing frequencies in the lower frequency region of said bandwidth; and adder means having the outputs of said first and said second comb filter means as inputs thereto.
Claim 12
Dependent Claim
146 words
In a colour television camera system having a video signal output of selected bandwidth, a circuit for correcting for the vertical component of aperture distortion, said circuit comprising in combination: first comb filter means connected to said video output signal for producing a vertically combed output signal having amplitude/frequency characteristic with amplitude maxima at odd multiples of half the line frequency, said first comb filter means including filter means for removing frequencies in the higher frequency range of said bandwidth; second comb filter means connected to said video output signal for producing a horizontally combed output signal having amplitude/frequency characteristic with maxima at integral multiples of the line frequency, said second comb filter means including filter means for removing frequencies in the lower frequency region of said bandwidth; and adder means having the outputs of said first and said second comb filter means as inputs thereto.
Claim 13
Dependent Claim
55 words
In a colour television camera system as defined in claim 9 wherein a further filter means for removing frequencies in the higher region of sand bandwidth is provided, said further filter means having said video signal output delayed by one line period as an input thereto and having an output connected to said adder means.
Claim 14
Dependent Claim
188 words
In a colour television camera system having a video signal output Eo of selected bandwidth, a circuit for correcting for the vertical component of aperture distinction, said circuit comprising in combination: first comb filter means for producing a vertically combed output signal of the form E1 - 1/2 (Eo + E2) in which E1 is said signal Eo delayed by one line period and E2 is said signal Eo delayed by two line periods, said first comb filter means including a first filter means for removing from the vertically combed output signal frequencies in the higher region of said bandwidth; second comb filter means for producing a horizontally combed output signal of the form E1 + 1/2 (Eo + E2) and including second filter means fOr removing from the horizontally combed output signal frequencies in the lower region of said bandwidth; and adder means having said vertically combed and said horizontally combed output signals as two inputs thereto and having a signal corresponding to said once delayed signal E1 as a third input for producing a corrected video output signal corrected for said vertical component of aperture distinction.
Claim 15
Dependent Claim
188 words
In a colour television camera system having a video signal output Eo of selected bandwidth, a circuit for correcting for the vertical component of aperture distinction, said circuit comprising in combination: first comb filter means for producing a vertically combed output signal of the form E1 - 1/2 (Eo + E2) in which E1 is said signal Eo delayed by one line period and E2 is said signal Eo delayed by two line periods, said first comb filter means including a first filter means for removing from the vertically combed output signal frequencies in the higher region of said bandwidth; second comb filter means for producing a horizontally combed output signal of the form E1 + 1/2 (Eo + E2) and including second filter means fOr removing from the horizontally combed output signal frequencies in the lower region of said bandwidth; and adder means having said vertically combed and said horizontally combed output signals as two inputs thereto and having a signal corresponding to said once delayed signal E1 as a third input for producing a corrected video output signal corrected for said vertical component of aperture distinction.
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) | 1976-07-02 | 1977-01-01 | 1977-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-02 | 1981-01-01 | 1981-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-02 | 1985-01-01 | 1985-07-03 | $7700.00 | Window Closed / Lapsed |