US3723644A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable frame rate recording system using speed measurement
Assignee: AT&T Inc
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Filing: 1972-04-24
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Granted: 1973-03-27
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Expires: 1992-04-24
Abstract
Abstract A variable frame rate video recording system utilizes the speed of movement in the video scene to vary the frame recording rate. The speed measurement signal is converted into a frame repetition signal. The frame repetition signal is applied to a switch control which prevents frames containing little movement or highly redundant information from entering a storage medium. With each recorded frame is stored the output signal of a counter which indicates the number of times each recorded frame is to be used for display. A switch control circuit in a readout circuit, in response to the stored output signal of the counter, causes each recorded frame to be repeated at the output terminal to maintain a constant frame rate.
Inventors
- 👤 B Haskell
- 👤 J Limb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:48
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/76; H04N5/78; H04N5/91; H04N5/915; H04N7/00; H04N7/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
301 words
A video recording system including a camera for scanning a scene to produce successive video frames of the scene at a predetermined rate and storage means for recording a video signal comprising: means for determining the speed of a moving object in a video scene comprising sampling means connected to said camera to change the analog video signal into successive picture elements, encoding means for providing a first digital signal indicative of the successive picture elements, first means for summing the absolute magnitude of the encoded differences between successive picture elements in each frame, second means for summing the absolute magnitude of the encoded differences between corresponding picture elements in successive frames, and third means for comparing the accumulated sum of said first means with the accumulated sum of said second means to generate a second signal indicative of the speed of a moving object in the video image; means for converting the second signal from said third means into a third digital signal indicative of the number of times a frame is shown; and switching means for completing input signal paths to said storage means under the influence of the third digital signal and counting means responsive to said switching means for producing an output signal indicative of the actual number of times a frame will be shown, said switching means completing the input signal paths to said storage means when the third digital signal is equal in value to the output signal of said counting means, said signal paths for the first digital signal and the output signal of said counting means being disrupted to vary the frame-recording rate in accordance with the speed of the moving object thereby minimizing the amount of information recorded in said storage means required to produce a video image of suitable visual quality.
Claim 2
Dependent Claim
301 words
A video recording system including a camera for scanning a scene to produce successive video frames of the scene at a predetermined rate and storage means for recording a video signal comprising: means for determining the speed of a moving object in a video scene comprising sampling means connected to said camera to change the analog video signal into successive picture elements, encoding means for providing a first digital signal indicative of the successive picture elements, first means for summing the absolute magnitude of the encoded differences between successive picture elements in each frame, second means for summing the absolute magnitude of the encoded differences between corresponding picture elements in successive frames, and third means for comparing the accumulated sum of said first means with the accumulated sum of said second means to generate a second signal indicative of the speed of a moving object in the video image; means for converting the second signal from said third means into a third digital signal indicative of the number of times a frame is shown; and switching means for completing input signal paths to said storage means under the influence of the third digital signal and counting means responsive to said switching means for producing an output signal indicative of the actual number of times a frame will be shown, said switching means completing the input signal paths to said storage means when the third digital signal is equal in value to the output signal of said counting means, said signal paths for the first digital signal and the output signal of said counting means being disrupted to vary the frame-recording rate in accordance with the speed of the moving object thereby minimizing the amount of information recorded in said storage means required to produce a video image of suitable visual quality.
Claim 3
Dependent Claim
53 words
The video recording system of claim 1 wherein said first means comprises means for delaying the first digital signal a picture element interval, means for subtracting the input from the output of said means for delaying, and means for storing the sum of the absolute magnitude of the differences between successive picture elements.
Claim 4
Dependent Claim
55 words
The video recording system of claim 1 wherein said second means comprises means for delaying the digital signal a frame interval, means for subtracting the input from the output signal of said means for delaying, and means for storing the sum of the absolute magnitude Of the differences between corresponding picture elements in successive frames.
Claim 5
Dependent Claim
37 words
The video recording system of claim 1 wherein said means for determining speed further comprises switching means for completing the signal paths to said third means only when the frame difference signal exceeds a predetermined threshold level.
Claim 6
Dependent Claim
73 words
The video recording system of claim 1 wherein the video recording system further comprises means for storing the third digital signal when said signal path to said storage means is open-circuited, said switching means comparing the current third digital signal with the stored value and closing said signal paths when the current value is less than the stored value to increase the frame recording rate when the speed of a moving object increases.
Claim 7
Dependent Claim
110 words
The video recording system of claim 1 wherein the output of said storage means is connected to a readout circuit comprising delaying means for delaying the video output signal from said storage means a frame interval, switching means for completing the signal path to the input of said delaying means, said switching means acting in response to the stored output signal of said counter means obtained from said storage means to open-circuit the signal path to said delaying means and to connect the output to the input of said delaying means to provide a repetition of the frame stored therein when the value of the stored output signal exceeds one.
Claim 8
Dependent Claim
71 words
The video recording system of claim 6 wherein the readout circuit further comprises counting means activated when said switching means recirculates the video frame in said delaying means, said switching means completing the signal path from said storage means to said delaying means when the output of said counting means in said readout circuit is equal in value to the stored output signal of said counting means in said recording circuit.
References Cited (Backward Citations)
US3520993A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |