Patent US1072248A successfully refreshed from Google Patents.
Patent US3912943A successfully refreshed from Google Patents.
US3912943A
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Video thresholder
Assignee: International Business Machines Corp
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Filing: 1974-08-09
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Granted: 1975-10-14
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Expires: 1994-08-09
Abstract
Abstract A two-valued digital signal is produced from an analog video signal by taking a fraction of the difference between a white peak signal and a black peak signal. The peak signals decay slowly between video pulses. A jump circuit changes one or both of the peak signals rapidly when the video signal has a certain relation to a delayed and level-shifted replica of the video signal.
Inventors
- 👤 Melvin G Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:07
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/10544; G06K7/10821; G06K7/10851; H; H03; H03K; H03K5/00; H03K5/01; H03K5/08; H03K5/082; H04; H04N; H04N1/00; H04N1/40; H04N1/403
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
144 words
A thresholder for converting an analog video signal into a two-valued digital output signal, comprising: delay means for producing a delayed signal from said video signal; offset means for producing a delayed offset signal having a different absolute amplitude from said delayed signal; follower means for storing a peak signal related to peak excursions of said video signal; divider means for producing a threshold signal from said peak signal; jump means for rapidly changing the amplitude of said threshold signal toward the amplitude of said video signal, when said video signal and said delayed offset signal bear a predetermined relation to each other; discriminating means for producing a first value of said output signal when a signal derived from said video signal exceeds said threshold signal and for producing the other value of said output signal when said threshold signal exceeds said derived signal.
Claim 2
Dependent Claim
144 words
A thresholder for converting an analog video signal into a two-valued digital output signal, comprising: delay means for producing a delayed signal from said video signal; offset means for producing a delayed offset signal having a different absolute amplitude from said delayed signal; follower means for storing a peak signal related to peak excursions of said video signal; divider means for producing a threshold signal from said peak signal; jump means for rapidly changing the amplitude of said threshold signal toward the amplitude of said video signal, when said video signal and said delayed offset signal bear a predetermined relation to each other; discriminating means for producing a first value of said output signal when a signal derived from said video signal exceeds said threshold signal and for producing the other value of said output signal when said threshold signal exceeds said derived signal.
Claim 3
Dependent Claim
20 words
A thresholder according to claim 1, wherein said follower means produces said peak signals from white areas on an article.
Claim 4
Dependent Claim
71 words
A thresholder according to claim 1, wherein said jump means comprises: a first discriminator for comparing said video signal and said delayed offset signal; a second discriminator for comparing said video signal and said peak signal; and a controlled source coupled to said first and second discriminators and to said follower means for rapidly changing said peak signal when said video signal bears a first relation to said delayed offset signal.
Claim 5
Dependent Claim
24 words
A thresholder according to claim 3, wherein said controlled source is enabled when said video signal bears a second relation to said peak signal.
Claim 6
Dependent Claim
49 words
A thresholder according to claim 4, wherein said controlled source comprises: a constant-current source coupled to said follower means; and a control transistor for enabling said constant-current source, said control transistor having a first electrode coupled to said first discriminator and a second electrode coupled to said second discriminator.
Claim 7
Dependent Claim
29 words
A thresholder according to claim 4, wherein said source is enabled when both said video signal exceeds saiD delayed offset signal and said peak signal exceeds said video signal.
Claim 8
Dependent Claim
29 words
A thresholder according to claim 4, wherein said source is enabled when both said delayed offset signal exceeds said video signal and said video signal exceeds said peak signal.
Claim 9
Dependent Claim
14 words
A thresholder according to claim 1, wherein said derived signal is said delayed signal.
Claim 10
Dependent Claim
30 words
A thresholder according to claim 1, wherein said follower means is adapted to change said peak signal slowly when said peak signal bears a predetermined relation to said video signal.
Claim 11
Dependent Claim
46 words
A thresholder according to claim 9, wherein said follower means is further adapted to store a further peak signal related to opposite peak excursions of said video signal and to change said second peak signal slowly when it bears a predetermined relation to said video signal.
Claim 12
Dependent Claim
31 words
A thresholder according to claim 10, wherein said divider means is adapted to produce said threshold signal as a predetermined fraction of a difference between said first and second peak signals.
Claim 13
Dependent Claim
51 words
A thresholder according to claim 10, further comprising: further offset means for producing a further delayed offset signal; further jump means for rapidly changing the amplitude of said further threshold signal toward said video signal when said video signal and said further offset signal bear a predetermined relation to each other.
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) | 1978-10-13 | 1979-04-14 | 1979-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-13 | 1983-04-14 | 1983-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-13 | 1987-04-14 | 1987-10-14 | $7700.00 | Window Closed / Lapsed |