US5373151A
Expired / Lapsed
US
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Optical system including focal plane array compensation technique for focusing and periodically defocusing a beam
Assignee: Raytheon Co
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Filing: 1993-10-04
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Granted: 1994-12-13
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Expires: 2013-10-04
Abstract
Abstract An imaging optical system is described including an array of photodetectors, each photodetector having a surface, and a focusing system for focusing a beam of electromagnetic infrared energy on the surface of at least one of the photodetectors. The focusing system further includes a technique for periodically defocusing the beam of electromagnetic infrared energy on the surface of at least one of the photodetectors. With such an arrangement, a scanning and focusing system is provided wherein fixed pattern noise can be decreased.
Inventors
- 👤 Robert A. Eckel, Jr.
- 👤 Gordon C. MacKenzie
- 👤 Joseph C. Ottney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:51
CPC Classifications
F; F41; F41G; F41G7/00; F41G7/20; F41G7/22; F41G7/2213; F41G7/001; F41G7/2253; F41G7/2273; F41G7/2293; G; G02; G02B; G02B13/00; G02B13/14; H; H04; H04N; H04N23/00; H04N23/20; H04N25/00; H04N25/60; H04N25/67; H04N25/671; H04N25/673; H04N25/674
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
97 words
An imaging optical system comprising: (a) an array of photodetectors, each photodetector having a surface; (b) means for focusing and periodically defocussing a beam of electromagnetic energy on the surface of at least one of the photodetectors, said focusing and periodically defocussing means comprising: (i) a primary mirror and a secondary mirror disposed in a catadioptric telescope arrangement and a plurality of relay lenses disposed within the beam of the electromagnetic energy; and (ii) means for dithering the secondary mirror for defocusing the beam of electromagnetic energy upon the surface of at least one of the photodetectors.
Claim 2
Dependent Claim
97 words
An imaging optical system comprising: (a) an array of photodetectors, each photodetector having a surface; (b) means for focusing and periodically defocussing a beam of electromagnetic energy on the surface of at least one of the photodetectors, said focusing and periodically defocussing means comprising: (i) a primary mirror and a secondary mirror disposed in a catadioptric telescope arrangement and a plurality of relay lenses disposed within the beam of the electromagnetic energy; and (ii) means for dithering the secondary mirror for defocusing the beam of electromagnetic energy upon the surface of at least one of the photodetectors.
Claim 3
Dependent Claim
67 words
The optical system as recited in claim 1 further comprising: (a) means, responsive to the array of photodetectors, for providing an in-focus image comprising an array of pixels; (b) means, responsive to the array of photodetectors, for providing an out-of-focus image comprising an array of pixels; and (c) means, responsive to the in-focus image and out-of-focus image, for providing a difference image comprising an array of pixels.
Claim 4
Dependent Claim
66 words
The imaging optical system as recited in claim 2 further comprising: (a) means for providing a single point reference image; (b) means for differencing the single point reference image with the in-focus image and passing the resultant thereof through a low pass digital filter to provide a filtered image; and (c) means for summing the difference image with the filtered image to provide a corrected image.
Claim 5
Dependent Claim
83 words
An imaging optical system for receiving a beam of electromagnetic energy comprising: (a) an optics assembly disposed within the beam of electromagnetic energy comprising a plurality of lenses disposed within the beam of electromagnetic energy to focus an image at an image plane; (b) a detector array disposed within the beam of the electromagnetic energy at the image plane to detect the electromagnetic energy; and (c) means for dithering one of the plurality of lenses for defocusing the image at the image plane.
Claim 6
Dependent Claim
83 words
An imaging optical system for receiving a beam of electromagnetic energy comprising: (a) an optics assembly disposed within the beam of electromagnetic energy comprising a plurality of lenses disposed within the beam of electromagnetic energy to focus an image at an image plane; (b) a detector array disposed within the beam of the electromagnetic energy at the image plane to detect the electromagnetic energy; and (c) means for dithering one of the plurality of lenses for defocusing the image at the image plane.
Claim 7
Dependent Claim
60 words
The imaging optical system as recited in claim 4 further comprising: (a) means, responsive to the detector array, for providing an in-focus image comprising an array of pixels and for providing an out-of-focus image comprising an array of pixels; and (b) means, responsive to the in-focus image and out-of-focus image, for providing a difference image comprising an array of pixels.
Claim 8
Dependent Claim
66 words
The imaging optical system as recited in claim 5 further comprising: (a) means for providing a single point reference image; (b) means for differencing the single point reference image with the in-focus image and passing the resultant thereof through a low pass digital filter to provide a filtered image; and (c) means for summing the difference image with the filtered image to provide a corrected image.
Claim 9
Independent Claim
138 words
A method of operating an imaging optical system comprising the steps of: (a) focusing a beam of infrared energy with a plurality of lenses on an array of photodetectors and forming an in-focus image comprising an array of pixels, each pixel represented by a digital word; (b) periodically defocusing the beam of infrared energy by dithering one of the plurality of lenses on the array of photodetectors and forming an out-of-focus image comprising an array of pixels, each pixel represented by a digital word; and (c) differencing the digital word of each pixel of the out-of-focus image with the digital word of a corresponding pixel of the in-focus image to provide a difference image comprising an array of pixels, each pixel represented by a digital word indicative of a limited field of view of the optical radar system.
Claim 10
Independent Claim
138 words
A method of operating an imaging optical system comprising the steps of: (a) focusing a beam of infrared energy with a plurality of lenses on an array of photodetectors and forming an in-focus image comprising an array of pixels, each pixel represented by a digital word; (b) periodically defocusing the beam of infrared energy by dithering one of the plurality of lenses on the array of photodetectors and forming an out-of-focus image comprising an array of pixels, each pixel represented by a digital word; and (c) differencing the digital word of each pixel of the out-of-focus image with the digital word of a corresponding pixel of the in-focus image to provide a difference image comprising an array of pixels, each pixel represented by a digital word indicative of a limited field of view of the optical radar system.
Claim 11
Dependent Claim
115 words
The method as recited in claim 7 further comprising the steps of: (a) providing a single point reference image comprising an array of pixels, each pixel represented by a digital word; (b) differencing the digital word of each pixel of the single point reference image with the digital word of a corresponding pixel of the in-focus image and passing the resultant thereof through a low pass digital filter to provide a filtered image comprising an array of pixels, each pixel represented by a digital word; and (c) summing the digital word of each pixel of the difference image with the digital word of a corresponding pixel of the filtered image to provide a corrected image.
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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) | 1997-12-12 | 1998-06-13 | 1998-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-12 | 2002-06-13 | 2002-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-12 | 2006-06-13 | 2006-12-13 | $7700.00 | Window Closed / Lapsed |