US3911212A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Threshold device for converting video signal to binary video signals and method of determining threshold level
Assignee: Artience Co Ltd
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Filing: 1974-07-30
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Granted: 1975-10-07
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Expires: 1994-07-30
Abstract
Abstract In an image analysis for document or a particle measuring system, a threshold circuit for providing a reference signal for comparison with a video signal derived from a television camera to provide a corresponding binary video signal. A monitoring device is provided for displaying on the screen two sample marks as well as an image of the character or particle being scanned. The two sample marks are position-shiftable on the screen so that they are shifted to the highest and lowest image intensity portions on the screen, respectively. The threshold circuit operates to sample and hold the video signal at those points of time corresponding to the two sample marks to provide the reference signal equal to the average of the sample values.
Inventors
- 👤 Kiyoshi Yoshizawa
- 👤 Kiichi Yamaya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:33
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/02; G01B11/022; G06; G06V; G06V10/00; G06V10/20; G06V10/28; H; H04; H04N; H04N1/00; H04N1/40; H04N1/403; H05; H05K; H05K3/00; H05K3/02; H05K3/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
260 words
A threshold device for converting a video signal derived from a television camera into a corresponding binary signal, comprising: a sync signal separator responsive to said video signal for deriving sync signals; a first sampling pulse generator responsive to said derived sync signals for generating a first sampling pulse; a second sampling pulse generator responsive to said derived sync signals for generating a second sampling pulse; a first sample hold circuit for sampling and holding said video signal in response to said first sampling pulse; a second sample hold circuit for sampling and holding said video signal in response to said second sampling pulse; a summing network responsive to said first and second sample hold circuit for providing a reference signal equal to the average of the sampled values of said video signal; a comparator responsive to said video and said reference signal for providing a binary video signal depending upon whether said video signal is larger than said reference signal; and a television monitor having a screen and responsive to said video signal for displaying an image of the object scanned by said television camera means being responsive to the sample pulse generator, to provide first and second sample marks on the screen at positions corresponding to said first and second sampling pulses; said first and second sampling pulse generators having adjustment means to vary the positions of said first and second sample marks on the screen so that said first and second sample marks are shifted to the highest and lowest image intensity portions on the screen, respectively.
Claim 2
Dependent Claim
260 words
A threshold device for converting a video signal derived from a television camera into a corresponding binary signal, comprising: a sync signal separator responsive to said video signal for deriving sync signals; a first sampling pulse generator responsive to said derived sync signals for generating a first sampling pulse; a second sampling pulse generator responsive to said derived sync signals for generating a second sampling pulse; a first sample hold circuit for sampling and holding said video signal in response to said first sampling pulse; a second sample hold circuit for sampling and holding said video signal in response to said second sampling pulse; a summing network responsive to said first and second sample hold circuit for providing a reference signal equal to the average of the sampled values of said video signal; a comparator responsive to said video and said reference signal for providing a binary video signal depending upon whether said video signal is larger than said reference signal; and a television monitor having a screen and responsive to said video signal for displaying an image of the object scanned by said television camera means being responsive to the sample pulse generator, to provide first and second sample marks on the screen at positions corresponding to said first and second sampling pulses; said first and second sampling pulse generators having adjustment means to vary the positions of said first and second sample marks on the screen so that said first and second sample marks are shifted to the highest and lowest image intensity portions on the screen, respectively.
Claim 3
Dependent Claim
29 words
A threshold device according to claim 1, in which said first and second sampling pulse generators include delay circuits for providing variable time delay to said derived sync signals.
Claim 4
Dependent Claim
88 words
A threshold device according to Claim 1, in which said summing network includes first and second buffer amplifiers responsive to the sampled video signals from said first and second sample hold circuits, respectively; first and second resistors having identical resistance and connected at their respective one ends to the outputs of said first and second buffer amplifiers; and a third buffer amplifier connected at its input to the other ends of said first and second resistors, the output of said third buffer amplifier being connected to said comparator.
Claim 5
Independent Claim
123 words
A method of determining a reference threshold against which a video signal derived from a television camera is compared to provide a corresponding binary video signal, comprising the steps of: displaying on a monitoring screen an image of the object being scanned by said television camera and two sample marks, each of said sample marks having a distinguishable brightness and being shiftable to an arbitrary point on said screen; shifting one of said two sample marks into a high image intensity region and the other into a low image intensity region on said screen; sampling said video signal at those points of time corresponding to said two sample marks; and averaging the sampled values of said video signals to provide said reference threshold.
Claim 6
Independent Claim
123 words
A method of determining a reference threshold against which a video signal derived from a television camera is compared to provide a corresponding binary video signal, comprising the steps of: displaying on a monitoring screen an image of the object being scanned by said television camera and two sample marks, each of said sample marks having a distinguishable brightness and being shiftable to an arbitrary point on said screen; shifting one of said two sample marks into a high image intensity region and the other into a low image intensity region on said screen; sampling said video signal at those points of time corresponding to said two sample marks; and averaging the sampled values of said video signals to provide said reference threshold.
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) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |