US4514059A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Incoherent optical heterodyne Fourier transformer
Assignee: United States Department of the Army
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Filing: 1982-09-15
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Granted: 1985-04-30
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Expires: 2002-09-15
Abstract
Abstract An apparatus for performing an incoherent optical Fourier transform inclu a source of incoherent light, means for generating and phase modulating a first zone plate, a second zone plate, means for detecting incoherent light processed by the apparatus, and means for filtering the output signal, thereby discriminating between the Fourier transform signal and background constant or bias signals. A method for performing incoherent optical Fourier transform is also disclosed.
Inventors
- 👤 Michael M. McDonnell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:20
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/42; G02B27/4233; G02B27/4255; G06; G06E; G06E3/00; G06E3/001; G06E3/003
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
101 words
A method for performing a Fourier transform of a transparent image, comprising: providing a first zone plate comprising alternating transparent and opaque zones; providing a second zone plate comprising alternating transparent and opaque zones; positioning the image between said first and second zone plates; passing incoherent light through said first zone plate, the image, and said second zone plate; phase modulating said first zone plate at a known rate; detecting the output from said second zone plate and generating a signal representative of the output; and filtering said signal to isolate therefrom signals of a frequency equal to said known rate.
Claim 2
Independent Claim
101 words
A method for performing a Fourier transform of a transparent image, comprising: providing a first zone plate comprising alternating transparent and opaque zones; providing a second zone plate comprising alternating transparent and opaque zones; positioning the image between said first and second zone plates; passing incoherent light through said first zone plate, the image, and said second zone plate; phase modulating said first zone plate at a known rate; detecting the output from said second zone plate and generating a signal representative of the output; and filtering said signal to isolate therefrom signals of a frequency equal to said known rate.
Claim 3
Independent Claim
95 words
A method for performing a Fourier transform of an opaque image, comprising: projecting a first zone plate comprising alternating light and dark zones onto the image; providing a second zone plate comprising alternating transparent and opaque zones; reflecting incoherent light from the image and passing the reflected light through said second zone plate; phase modulating said first zone plate at a known rate; detecting the output from said second zone plate and generating a signal representative of the output; and filtering said signal to isolate therefrom signals of a frequency equal to said known rate.
Claim 4
Independent Claim
95 words
A method for performing a Fourier transform of an opaque image, comprising: projecting a first zone plate comprising alternating light and dark zones onto the image; providing a second zone plate comprising alternating transparent and opaque zones; reflecting incoherent light from the image and passing the reflected light through said second zone plate; phase modulating said first zone plate at a known rate; detecting the output from said second zone plate and generating a signal representative of the output; and filtering said signal to isolate therefrom signals of a frequency equal to said known rate.
Claim 5
Dependent Claim
19 words
A method as set forth in claim 1 or 2, comprising projecting said first zone plate from an interferometer.
Claim 6
Dependent Claim
21 words
A method as set forth in claim 1, comprising projecting said first zone plate from an interferometer onto a transparent screen.
Claim 7
Dependent Claim
37 words
A method as set forth in claim 1 or 2, wherein: said first zone plate is projected from an interferometer; and said first zone plate is modulated by varying the frequency of light emitted from said interferometer.
Claim 8
Dependent Claim
47 words
A method as set forth in claim 1 or 2, wherein: said first zone plate is projected from an interferometer, said interferometer comprising means defining separate paths for light emitted therefrom; and said first zone plate is modulated by varying the length of one of said paths.
Claim 9
Dependent Claim
56 words
A method as set forth in claim 1 or 2 wherein: said alternating zones of said first zone plate are concentrically arranged at respective radial distances from the center of said first zone plate; and said phase modulation comprises varying the radial distances of the respective alternating zones from the center of the first zone plate.
Claim 10
Dependent Claim
64 words
Apparatus for performing an incoherent optical Fourier transform of an image, comprising: a source of incoherent light; means for generating and for phase modulating a first zone plate; a second zone plate spaced from said first zone plate; means for detecting incoherent light and generating a signal spaced from said second zone plate; and means for filtering the signal generated by said detecting means.
Claim 11
Dependent Claim
64 words
Apparatus for performing an incoherent optical Fourier transform of an image, comprising: a source of incoherent light; means for generating and for phase modulating a first zone plate; a second zone plate spaced from said first zone plate; means for detecting incoherent light and generating a signal spaced from said second zone plate; and means for filtering the signal generated by said detecting means.
Claim 12
Dependent Claim
36 words
Apparatus as set forth in claim 8, wherein said generating and phase modulating means modulates said first zone plate at a known rate, and said filtering means isolates signals of a frequency equal to said rate.
Claim 13
Dependent Claim
37 words
Apparatus as set forth in claim 8, wherein said generating and modulating means comprises an interferometer including means for defining separate light paths through said interferometer, and means for varying the length of one of said paths.
Claim 14
Dependent Claim
28 words
Apparatus as set forth in claim 8, wherein said generating and modulating means comprises an interferometer including means for varying the frequency of light emitted by said source.
Claim 15
Dependent Claim
35 words
Apparatus as set forth in claim 8, wherein each of said first and second zone plates comprises alternating concentric transparent and opaque zones spaced at respective radial distances from the center of each zone plate.
Claim 16
Dependent Claim
36 words
Apparatus as set forth in claim 12, wherein said means for phase modulating said first zone plate comprises means for varying the radial distances of said alternating zones from the center of said first zone plate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-04-29 | 1988-10-29 | 1989-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-29 | 1992-10-29 | 1993-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-29 | 1996-10-29 | 1997-04-30 | $7700.00 | Window Closed / Lapsed |