US4989086A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultra wide field-of-regard multispectral imaging radiometer
Assignee: Northrop Grumman Corp
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Filing: 1988-09-29
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Granted: 1991-01-29
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Expires: 2008-09-29
Abstract
Abstract An imaging radiometer for scanning an area of interest from a platform moving in an orbital trajectory comprises at least one moving scanning mirror directed toward the area of interest. The mirror produces a changing scan area image representing a portion of the area of interest within the scan area of the mirror. A fixed optical viewer is mounted on the platform for viewing the scan area image and directing the image along its optical path. A detector in the optical path receives the changing scan area image over a selected time interval and periodically produces an electrical output, each output representing a different scan area image of the mirror over each time interval. In one embodiment the detector has a plurality of areas of different spectral response. Image motion compensation, electronically controlled light intensity gain and electronically controlled image size correction are incorporated in the apparatus.
Inventors
- 👤 Fred L. Schaff
- 👤 Leslie L. Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:50
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/2823; G01C; G01C11/00; G01C11/02; G01J3/30; G01J3/36; H; H04; H04N; H04N23/00; H04N23/20; H04N23/23; H04N25/00; H04N25/20; H04N25/21; H04N3/00; H04N3/02; H04N3/08; H04N3/09
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
260 words
An imaging radiometer mounted on a platform moving in a uniform trajectory in an in-track direction, said radiometer for scanning an area of interest laterally of the in-track direction in a cross-track direction, said area defined by a field-of-view dimension in the in-track direction and a field-of-regard dimension in the cross-track direction, said imaging radiometer comprising: at least one scanning mirror having a viewing area directed toward the area of interest, the mirror being movably mounted on the platform for scanning between extreme ends of the field-of-regard in the cross-track direction of the platform, said mirror producing an image representing a portion of the area of interest within the viewing area of the mirror; means for driving the mirror at near-contant rate relative to the extremes of the field-of-regard and inversely of the in-track direction of the platform, the image produced by the mirror changing with the position of the mirror relative to the portion of the area of the interest within the viewing area of the mirror; an image forming means mounted on the platform in fixed relation with the mirror for viewing the mirror and redirecting the changing image along an optical path; and multi-element detector means mounted in the optical path in fixed relationship with the image forming means for receiving the changing image thereon over a selected time interval and periodically producing an electrical output, each output representing a different image over each time interval, selected elements of the detector means being responsive to receive in successive time intervals, the same portion of the changing image.
Claim 2
Dependent Claim
260 words
An imaging radiometer mounted on a platform moving in a uniform trajectory in an in-track direction, said radiometer for scanning an area of interest laterally of the in-track direction in a cross-track direction, said area defined by a field-of-view dimension in the in-track direction and a field-of-regard dimension in the cross-track direction, said imaging radiometer comprising: at least one scanning mirror having a viewing area directed toward the area of interest, the mirror being movably mounted on the platform for scanning between extreme ends of the field-of-regard in the cross-track direction of the platform, said mirror producing an image representing a portion of the area of interest within the viewing area of the mirror; means for driving the mirror at near-contant rate relative to the extremes of the field-of-regard and inversely of the in-track direction of the platform, the image produced by the mirror changing with the position of the mirror relative to the portion of the area of the interest within the viewing area of the mirror; an image forming means mounted on the platform in fixed relation with the mirror for viewing the mirror and redirecting the changing image along an optical path; and multi-element detector means mounted in the optical path in fixed relationship with the image forming means for receiving the changing image thereon over a selected time interval and periodically producing an electrical output, each output representing a different image over each time interval, selected elements of the detector means being responsive to receive in successive time intervals, the same portion of the changing image.
Claim 3
Dependent Claim
108 words
The radiometer of claim 1, wherein the selected elements of the detector are aligned in a row and each of said elements is responsive to light energy from a portion of the image for producing a signal indicative thereof, and further including storage means for storing the signal of each element corresponding to a particular portion of the image and integrating means for combining the signals corresponding to the particular portion of the image so that each of said particular portions is viewed a multiplicity of times in succession over the selected time interval during a scan across the field-of-regard to increase the signal output of the detector.
Claim 4
Dependent Claim
38 words
The radiometer of claim 2, wherein the storage means includes a register having inputs coupled to selected elements for receiving the output of each element, and the integrating means includes an amplifier for reading out the register sequentially.
Claim 5
Dependent Claim
40 words
The radiometer of claim 3, further including gain control means for modifying the output of the amplifier in accordance with the relative position of the mirror with respect to the extremes of the field-of-regard and illumination conditions over the field-of-regard.
Claim 6
Dependent Claim
78 words
The radiometer of claim 4, wherein the area of interest appears distorted in accordance with changes in slant range across the field-of-regard and the gain control means for modifying the output of the amplifier in accordance with the position of the mirror relative to the field-of-regard includes an algorithm and electronic means to select the effective physical size of the detector to compensate for changing area of interest caused by changes in the slant range across the field-of-regard.
Claim 7
Dependent Claim
26 words
The radiometer of claim 1, wherein the detector comprises a discrete array of k×m discrete elements including a subset of an n×m array of discrete elements.
Claim 8
Dependent Claim
20 words
The radiometer of claim 1, wherein the detector comprises a k×m array of elements in a monolithic integrated circuit device.
Claim 9
Dependent Claim
16 words
The radiometer of claim 1, wherein the mirror scans the field-of-regard in adjacent geometrically contiguous bands.
Claim 10
Dependent Claim
16 words
The radiometer of claim 1, wherein the areas of different spectral response includes separate detection devices.
Claim 11
Dependent Claim
39 words
The radiometer of claim 1, wherein said detector means has multi-element areas of different spectral response, each area being aligned for viewing the changing image at different wavelengths in response to the elements for spatial registration within reach other.
Claim 12
Dependent Claim
30 words
The radiometer of claim 10, wherein the areas of different spectral response are integrated in one device and further includes filter means for each area in integrated overlying relation therewith.
Claim 13
Dependent Claim
19 words
The radiometer of claim 1, wherein the mirror is mounted about a mirror axis aligned with the in-track direction.
Claim 14
Dependent Claim
25 words
The radiometer of claim 12, wherein the mirror is mounted relative to the mirror axis for resetting the mirror at the extremes of the field-of-regard.
Claim 15
Dependent Claim
25 words
The radiometer of claim 1, wherein the mirror is mounted for compound motion in the direction of the field-of-regard and the direction of the field-of-view.
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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) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |