US4468703A
Expired / Lapsed
US
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Image signal processing device
Assignee: Fujifilm Business Innovation Corp
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Filing: 1982-05-14
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Granted: 1984-08-28
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Expires: 2002-05-14
Abstract
Abstract An image signal processing device uses an automatically varied threshold value calculated from the average density and the density distribution of an original (document, etc). The threshold value is periodically updated at predetermined intervals, so that the overall image may be reproduced with high fidelity.
Inventors
- 👤 Fukumi Fujiwara
- 👤 Yoshio Arai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:58
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/403
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
77 words
An image signal processing device, comprising: means for determining an average value x of an image signal over a predetermined period of time; means for determining a density distribution g(y) of said image signal over said predetermined period of time; means for calculating a threshold value α from said average value x and said density distribution g(y); and voltage comparator means for comparing said image signal with said threshold value α, to output a binary-coded image signal.
Claim 2
Dependent Claim
77 words
An image signal processing device, comprising: means for determining an average value x of an image signal over a predetermined period of time; means for determining a density distribution g(y) of said image signal over said predetermined period of time; means for calculating a threshold value α from said average value x and said density distribution g(y); and voltage comparator means for comparing said image signal with said threshold value α, to output a binary-coded image signal.
Claim 3
Dependent Claim
22 words
A device as claimed in claim 1, said calculating means comprising a threshold value calculation circuit, said threshold value α satisfying: ##EQU8##
Claim 4
Independent Claim
29 words
A device as claimed in claims 1 or 2, further comprising means for delaying said image signal, said voltage comparator means operating to binarily encode said delayed image signal.
Claim 5
Independent Claim
41 words
A device as claimed in claims 1 or 2, including integrating circuit means for integrating said image signal over said predetermined period of time, said average value determining means determining said average value from an output of said integrating circuit means.
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) | 1987-08-28 | 1988-02-27 | 1988-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-28 | 1992-02-27 | 1992-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-28 | 1996-02-27 | 1996-08-28 | $7700.00 | Window Closed / Lapsed |