US4841376A
Expired / Lapsed
US
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Shading correcting method enabling prevention of effect of noise and apparatus therefor
Assignee: Konica Minolta Inc
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Filing: 1987-08-03
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Granted: 1989-06-20
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Expires: 2007-08-03
Abstract
Abstract A method of and apparatus for shading correction wherein a reference voltage of an A/D converter converting an image signal into a digital signal is set as a shading correction signal. The image signal and the shading correction signal are designed to be of different level from each other in the timing out of the effective period of the image signal. The shading correction signal is outputted in the timing during the effective period of the image signal and the reference voltage is outputted in the timing out of the effective period of the image signal.
Inventors
- 👤 Hiroyuki Yamamoto
- 👤 Masahiko Matsunawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:38
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/403; H04N1/407; H04N1/4076; H04N1/4078
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
100 words
A shading correcting apparatus comprising an A/D converter which converts an image signal into a digital signal and a reference voltage switching circuit which switches over a shading correction signal set as a first reference voltage of said A/D converter and a reference signal being set as a second reference voltage and different from said correction signal and applies same on said A/D converter, wherein the aforesaid first reference Voltage is outputted during an effective period of an image signal by said reference voltage switching circuit while the aforesaid second reference voltage is outputted thereby out of the effective period.
Claim 2
Dependent Claim
100 words
A shading correcting apparatus comprising an A/D converter which converts an image signal into a digital signal and a reference voltage switching circuit which switches over a shading correction signal set as a first reference voltage of said A/D converter and a reference signal being set as a second reference voltage and different from said correction signal and applies same on said A/D converter, wherein the aforesaid first reference Voltage is outputted during an effective period of an image signal by said reference voltage switching circuit while the aforesaid second reference voltage is outputted thereby out of the effective period.
Claim 3
Dependent Claim
47 words
A shading correcting apparatus comprising means for A/D converting an image signal into a digital signal based on a reference voltage, a first reference voltage generating means, a second reference voltage generating means, and means for switching said reference signal based on an effective signal of image.
Claim 4
Dependent Claim
47 words
A shading correcting apparatus comprising means for A/D converting an image signal into a digital signal based on a reference voltage, a first reference voltage generating means, a second reference voltage generating means, and means for switching said reference signal based on an effective signal of image.
References Cited (Backward Citations)
US4237495A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-19 | 1992-12-19 | 1993-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-19 | 1996-12-19 | 1997-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-19 | 2000-12-19 | 2001-06-20 | $7700.00 | Window Closed / Lapsed |