US4748677A
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Image processing apparatus
Assignee: Canon Inc
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Filing: 1985-10-21
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Granted: 1988-05-31
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Expires: 2005-10-21
Abstract
Abstract An image processing apparatus has analog image signal generator converter for converting an analog image signal generated by said analog image generator to a digital image signal, a comparator for comparing said image signal with a predetermined reference, and a controller for controlling the image signal in accordance with an output of the comparator to maintain a level or again of the image signal at a constant level.
Inventors
- 👤 Yoshikazu Yokomizo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:49
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/401
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
114 words
Signal processing apparatus comprising: an A/D converter for converting an input analog signal to a first digital signal; level control means operable to compare the value of the first digital signal at a first time with a first predetermined digital value to provide a first feedback signal to control the level of the input analog signal; gain control means operable to compare the value of the first digital signal at a second time with a second predetermined digital value to provide a second feedback signal to control gain of the input analog signal; and digital process means for performing a predetermined digital process on said first digital signal to produce a second digital signal.
Claim 2
Dependent Claim
114 words
Signal processing apparatus comprising: an A/D converter for converting an input analog signal to a first digital signal; level control means operable to compare the value of the first digital signal at a first time with a first predetermined digital value to provide a first feedback signal to control the level of the input analog signal; gain control means operable to compare the value of the first digital signal at a second time with a second predetermined digital value to provide a second feedback signal to control gain of the input analog signal; and digital process means for performing a predetermined digital process on said first digital signal to produce a second digital signal.
Claim 3
Dependent Claim
27 words
Signal processing apparatus according to claim 1, wherein said level control means includes an adder circuit for adding said first feedback signal to said input analog signal.
Claim 4
Dependent Claim
29 words
Signal processing apparatus according to claim 1 or 2, wherein said gain control means includes a multiplier circuit for multiplying said input analog signal by said second feedback signal.
Claim 5
Dependent Claim
16 words
Signal processing apparatus according to claim 1, wherein said input analog signal is an image signal.
Claim 6
Dependent Claim
24 words
Signal processing apparatus according to claim 4, wherein the value of the first digital signal at said first time represents a reference black level.
Claim 7
Dependent Claim
23 words
Signal processing apparatus according to claim 4 or 5, wherein the value of the first digital signal at the second time represents white.
Claim 8
Dependent Claim
38 words
Signal processing apparatus according to claim 6, including peak detector means for detecting the peak value of the first digital signal, said gain control means being operable to compare said peak value with said second predetermined digital value.
Claim 9
Dependent Claim
19 words
Signal processing apparatus according to claim 4 or 5, wherein said digital process means includes an outline emphasis circuit.
Claim 10
Dependent Claim
19 words
Signal processing apparatus according to claim 4 or 5, wherein said digital process means includes a dither process circuit.
Claim 11
Dependent Claim
25 words
Signal processing apparatus according to claim 4 or 5, further including reader means for reading an image to be read to generate said image signal.
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) | 1991-05-31 | 1991-11-30 | 1992-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-31 | 1995-11-30 | 1996-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-31 | 1999-11-30 | 2000-05-31 | $7700.00 | Window Closed / Lapsed |