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US5268575A
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Infrared observing system
Assignee: Fujitsu Ltd
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Filing: 1992-07-28
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Granted: 1993-12-07
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Expires: 2012-07-28
Abstract
Abstract An infrared observing system is provided such that, after an infrared-ray emitted from an optical/scanning system is converted into an infrared-ray image signal by an infrared detector, an unnecessary high frequency component of the infrared image signal is filtered by a lowpass filter to cut off a high frequency region noise and the output thereof is represented on a display unit. Before or after the lowpass filter, a highpass filter is provided that has a reverse frequency transfer characteristic to a first inclination attenuated frequency transfer characteristic.
Inventors
- 👤 Masami Tajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:28
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/20; H04N5/205; H04N23/00; H04N23/80; H04N23/81; H04N23/20
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
85 words
An infrared observing system that, after an infrared-ray emitted from an optical/scanning system is converted into an infrared-ray image signal by an infrared detector, an unnecessary high frequency component of said infrared image signal is filtered by a lowpass filter to cut off a high frequency region noise and the output thereof is represented on a display unit, wherein before or after said lowpass filter, a highpass filter that has a reverse transfer frequency characteristic to a first inclination attenuated transfer frequency characteristic is provided.
Claim 2
Dependent Claim
85 words
An infrared observing system that, after an infrared-ray emitted from an optical/scanning system is converted into an infrared-ray image signal by an infrared detector, an unnecessary high frequency component of said infrared image signal is filtered by a lowpass filter to cut off a high frequency region noise and the output thereof is represented on a display unit, wherein before or after said lowpass filter, a highpass filter that has a reverse transfer frequency characteristic to a first inclination attenuated transfer frequency characteristic is provided.
Claim 3
Dependent Claim
47 words
An infrared observing system according to claim 1, wherein before said lowpass filter a second lowpass filter that has an approximation of a reverse transfer frequency characteristic of SINC function for showing a transfer characteristic of said infrared detector is cascade-connected therewith by at least two stages.
Claim 4
Dependent Claim
25 words
An infrared observing system according to claim 1, wherein after said lowpass filter, a second lowpass filter is cascade-connected therewith in at least two stages.
Claim 5
Dependent Claim
53 words
An infrared observing system according to claim 1, wherein the modulation transfer function of the whole electrical circuit system is represented by ##EQU8## where MTF CCT is a modulation transfer function of the whole electrical circuit system, f s is spatial frequency, Ω is an instantaneous field of view and P o ≈1/(inclination).
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) | 1996-12-06 | 1997-06-07 | 1997-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-12-06 | 2001-06-07 | 2001-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-12-06 | 2005-06-07 | 2005-12-07 | $7700.00 | Window Closed / Lapsed |