Patent US3848129A successfully refreshed from Google Patents.
US3848129A
Expired / Lapsed
US
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Spectral discriminating radiation detection apparatus
Assignee: Lockheed Martin Corp
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Filing: 1973-08-24
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Granted: 1974-11-12
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Expires: 1993-08-24
Abstract
Abstract Radiation detection apparatus which is capable of discriminating between radiations having different spectral characteristics such as between an aircraft or missile and a cloud or a flare. A spinning reticle carrying a pair of spectral filters is arranged in the path of incident radiation upon a detector cell such that during each reticle revolution, the detector cell is illuminated by radiation which passes through one of the filters and then through the other of the filters. One of the spectral filters is given a passband which matches the wavelength band in which the true target radiation is maximum (infrared region) and the other spectral filter is given a passband in the wavelength band (near visible infrared region) where the false target radiation is much more intense than that of the true target. The infrared or long wavelength filtered signal sample and near visible or short wavelength filtered signal sample are then separated from one another temporarily stored and compared with one another to detect true targets as distinguished from false targets.
Inventors
- 👤 B Figler
- 👤 T Nussdorfer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:17
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/314; G01S; G01S3/00; G01S3/78; G01S3/781; G01S3/782; G01S3/783; G06; G06V; G06V10/00; G06V10/20; G06V10/255
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
207 words
Radiation detection apparatus for discriminating between radiations which have different spectral distributions; said apparatus comprising: an optical device for collecting incident radiations and focusing same; a filter for filtering the collected and focused radiations; a detector element for converting the filtered radiations into an electrical signal; said filter including a. a revolving reticle for spatially filtering the collected radiations; b. first and second bandpass spectral filters which pass radiations of long and relatively short wavelength, respectively, said spectral filters being so arranged on said reticle and said detector element being so located that the detector element receives filtered radiation from the first and second filters during first and second portions, respectively, of a reticle revolution; means for producing first and second sampling signals during said first and second reticle revolution portions, respectively; means responsive to the first and second sampling signals to convert said electrical signal produced by the detector element into first and second sequences of signal samples indicative of long and short wavelength filtered radiation, respectively; means for comparing the first and second sequences of signal samples with one another to produce a comparison signal; and means for producing a target signal when the amplitude of said comparison signal at least equals a predetermined value.
Claim 2
Dependent Claim
207 words
Radiation detection apparatus for discriminating between radiations which have different spectral distributions; said apparatus comprising: an optical device for collecting incident radiations and focusing same; a filter for filtering the collected and focused radiations; a detector element for converting the filtered radiations into an electrical signal; said filter including a. a revolving reticle for spatially filtering the collected radiations; b. first and second bandpass spectral filters which pass radiations of long and relatively short wavelength, respectively, said spectral filters being so arranged on said reticle and said detector element being so located that the detector element receives filtered radiation from the first and second filters during first and second portions, respectively, of a reticle revolution; means for producing first and second sampling signals during said first and second reticle revolution portions, respectively; means responsive to the first and second sampling signals to convert said electrical signal produced by the detector element into first and second sequences of signal samples indicative of long and short wavelength filtered radiation, respectively; means for comparing the first and second sequences of signal samples with one another to produce a comparison signal; and means for producing a target signal when the amplitude of said comparison signal at least equals a predetermined value.
Claim 3
Dependent Claim
37 words
Radiation detection apparatus as claimed in claim 1 and further including means for enabling and inhibiting said target signal producing means whenever said long wavelength filtered signal is greater than and less than, respectively, a reference value.
Claim 4
Dependent Claim
65 words
Radiation detection apparatus as set forth in claim 2 wherein said comparison means includes amplifier means for multiplying the second signal sample sequence by a constant K and difference amplifier means for taking the difference between the first sequence of signal samples and the second sequence of signal samples multiplied by K so as to produce a difference signal which corresponds to said comparison signal.
Claim 5
Dependent Claim
60 words
Radiation detection apparatus as set forth in claim 3 wherein said signal conversion means includes first and second analog switches responsive to the first and second sampling signals to convert the electrical signal into said first and second sequences and signal storage means for storing each said signal sample during the revolution portion when its associated switch is turned off.
Claim 6
Dependent Claim
102 words
Radiation detection apparatus as set forth in claim 4 wherein said sampling signal producing means includes a narrow annular band of mirrorlike material disposed upon one of said spectral filters near the outer circumference of the reticle, a light storage and light sensing unit disposed adjacent said annular band with the light source emitting light directed towards said annular band and the light sensor producing an output signal having first and second values corresponding to the presence and absence of said mirrorlike band, and signal processing means responsive to the light sensor output signal to produce said first and second sampling signals.
Claim 7
Dependent Claim
44 words
Radiation detection apparatus as set forth in claim 5 wherein said target signal producing means comprises a coincidence gate having a first input coupled to receive said comparison signal and a second input coupled to receive the output of said enabling and inhibiting 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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |