Patent US5216484A successfully refreshed from Google Patents.
US5216484A
Expired / Lapsed
US
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Real-time imaging spectrometer
Assignee: National Aeronautics and Space Administration
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Filing: 1991-12-09
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Granted: 1993-06-01
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Expires: 2011-12-09
Abstract
Abstract An improved AOTF-based imaging spectrometer that has ability to electronically set the bandpass wavelength of an AOTF to any desired value in its wide tuning range, provides significant observational flexibility. This allows observations to be tailored in real-time and enables the spectrometer to address a wide range of objectives and permits real-time modification of the observational parameters, such as in flight or in other situations in which only remote control is possible. Various improvements in optical architecture provide simplified magnification variability, improved image resolution and light throughput efficiency and reduced sensitivity to ambient light. A preferred embodiment employs a camera zoom lens as the input lens. A TeO 2 AOTF and a relay lens are placed at selected distances behind the back focal plane of the input lens, respectively. A charge coupled device (CCD) camera, which comprises a camera, camera zoom lens and a CCD detector is placed at a selected distance behind the relay lens. An RF signal generator is used to drive the AOTF. Two embodiments of the invention are disclosed herein. One operates in the visible/near-infrared domain, in the wavelength range of 0.48 to 0.76 microns. The other operates in the infrared wavelength range of 1.2 to 2.5 microns.
Inventors
- 👤 Tien-Hsin Chao
- 👤 Li-Jen Cheng Cheng
- 👤 Jeffrey W. Yu
- 👤 James L. Lambert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:28
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/12; G01J3/1256; G01J3/28; G01J3/2823; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/3563; G01N21/359
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
129 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said filter optical wavelength passband is in the range of 0.4 to 5.0 microns.
Claim 2
Dependent Claim
129 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said filter optical wavelength passband is in the range of 0.4 to 5.0 microns.
Claim 3
Dependent Claim
131 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said selected frequency of said RF signal is in the range of 50 to 90 MHz.
Claim 4
Dependent Claim
131 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said selected frequency of said RF signal is in the range of 50 to 90 MHz.
Claim 5
Dependent Claim
121 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said controlling means comprises a computer.
Claim 6
Dependent Claim
121 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said controlling means comprises a computer.
Claim 7
Dependent Claim
121 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said detector comprises a charge-coupled device.
Claim 8
Dependent Claim
121 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said detector comprises a charge-coupled device.
Claim 9
Dependent Claim
126 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said detector comprises a charge-coupled device detector within a CCD camera.
Claim 10
Dependent Claim
126 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said detector comprises a charge-coupled device detector within a CCD camera.
Claim 11
Dependent Claim
122 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said detector comprises a HgCdTe detector array.
Claim 12
Dependent Claim
122 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said detector comprises a HgCdTe detector array.
Claim 13
Dependent Claim
142 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said output optics are positioned relative to said filter to receive only one polarization of light therefrom without the use of a spatial filter at said detector.
Claim 14
Dependent Claim
142 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said output optics are positioned relative to said filter to receive only one polarization of light therefrom without the use of a spatial filter at said detector.
Claim 15
Dependent Claim
127 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said output optics comprises a zoom lens mounted directly on said detector.
Claim 16
Dependent Claim
127 words
An imaging spectrometer comprising an acousto-optic tunable filter of the type having an optical wavelength passband which is dependent on the selected frequency of an RF signal applied to said filter; input optics forming an intermediate image plane for directing incident image light into said filter within a field of view of said filter; a detector having an image plane for receiving image light passed by said filter; output optics positioned between said filter and said detector for producing a focussed image on said detector image plane; an RF signal source for applying said RF signal to said filter; and means for controlling said source for generating an RF signal having said selected frequency; wherein said output optics comprises a zoom lens mounted directly on said detector.
Claim 17
Dependent Claim
95 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof, and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said AOTF optical wavelength passband is in the range of 0.4 to 5.0 microns.
Claim 18
Dependent Claim
95 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof, and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said AOTF optical wavelength passband is in the range of 0.4 to 5.0 microns.
Claim 19
Dependent Claim
96 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said frequency of said RF signal is in the range of 50 to 90 MHz.
Claim 20
Dependent Claim
96 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said frequency of said RF signal is in the range of 50 to 90 MHz.
Claim 21
Dependent Claim
87 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said controlling means comprises a computer.
Claim 22
Dependent Claim
87 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said controlling means comprises a computer.
Claim 23
Dependent Claim
87 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said detector comprises a charge-coupled device.
Claim 24
Dependent Claim
87 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said detector comprises a charge-coupled device.
Claim 25
Dependent Claim
92 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said detector comprises a charge-coupled device detector within a CCD camera.
Claim 26
Dependent Claim
92 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said detector comprises a charge-coupled device detector within a CCD camera.
Claim 27
Dependent Claim
88 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said detector comprises a HgCdTe detector array.
Claim 28
Dependent Claim
88 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said detector comprises a HgCdTe detector array.
Claim 29
Dependent Claim
108 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said imaging lenses are positioned relative to said AOTF to receive only one polarization of light therefrom without the use of a spatial filter at said detector.
Claim 30
Dependent Claim
108 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said imaging lenses are positioned relative to said AOTF to receive only one polarization of light therefrom without the use of a spatial filter at said detector.
Claim 31
Dependent Claim
93 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said imaging lenses comprise a zoom lens mounted directly to said detector.
Claim 32
Dependent Claim
93 words
An imaging spectrometer comprising foreoptics for collecting light incident on said spectrometer; an AOTF positioned substantially at an intermediate imaging plane relative to said foreoptics for receiving said collected light; imaging lenses for focussing an image passed by said AOTF; a detector for detecting said focussed image; an RF signal generator connected to said AOTF for altering the optical passband thereof; and means for controlling the frequency of said RF signal generator for selecting the optical wavelength of said AOTF; wherein said imaging lenses comprise a zoom lens mounted directly to said detector.
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