Methods, systems, and apparatus for imaging spectroscopy
First Claim
1. A system for imaging spectroscopy of an object, the system comprising:
- an interferometer, in optical communication with the object, to delay a first portion of an object beam from the object with respect to a second portion of the object beam by a delay period, the delay period proportional to an optical path length difference defined by a first optical element and a second optical element;
a first detector array, in optical communication with the interferometer, to sense at least one object interference pattern between the first portion of the object beam and the second portion of the object beam, the at least one object interference pattern representing a spectroscopic image of at least a portion of the object;
a reference beam source, in optical communication with the interferometer, to illuminate the first optical element with a first portion of a reference beam and the second optical element with a second portion of the reference beam; and
a second detector array, in optical communication with the interferometer, to sense a reference interference pattern between the first portion of the reference beam and the second portion of the reference beam, the reference interference pattern representing a position of the first optical element with respect to the second optical element.
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Accused Products
Abstract
Imaging spectrometers can be used to generate hyperspectral images for medical diagnoses, contaminant detection, and food safety inspections, among other applications. An exemplary imaging spectrometer includes an integrated position sensing array that measures the relative positions of the interferometer components based on an interference pattern generated by illuminating the interferometer with a reference beam. Such an imaging spectrometer includes a processor that controls the interferometer component position by actuating a voice coil and several piezo-electric elements to align the components with respect to each other and to provide a desired optical path length mismatch between the interferometer arms. In some cases, the processor may use feedback and feed forward control, possibly based on the actuators'"'"' transfer functions, for more precise positioning. The processor may also implement adaptive and recursive spectral sampling to reduce the image acquisition period.
25 Citations
27 Claims
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1. A system for imaging spectroscopy of an object, the system comprising:
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an interferometer, in optical communication with the object, to delay a first portion of an object beam from the object with respect to a second portion of the object beam by a delay period, the delay period proportional to an optical path length difference defined by a first optical element and a second optical element; a first detector array, in optical communication with the interferometer, to sense at least one object interference pattern between the first portion of the object beam and the second portion of the object beam, the at least one object interference pattern representing a spectroscopic image of at least a portion of the object; a reference beam source, in optical communication with the interferometer, to illuminate the first optical element with a first portion of a reference beam and the second optical element with a second portion of the reference beam; and a second detector array, in optical communication with the interferometer, to sense a reference interference pattern between the first portion of the reference beam and the second portion of the reference beam, the reference interference pattern representing a position of the first optical element with respect to the second optical element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of imaging spectroscopy, the method comprising:
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(A) receiving an object beam from an object; (B) delaying, with an interferometer including a first optical element and a second optical element, a first portion of the object beam with respect to a second portion of the object beam by a delay period, the delay period proportional to an optical path length difference defined by the first optical element and the second optical element; (C) sensing, with a first detector array, at least one object interference pattern between the first portion of the object beam and the second portion of the object beam, the at least one object interference pattern representing a spectroscopic image of at least a portion of the object; (D) illuminating the first optical element with a first portion of a reference beam and the second optical element with a second portion of the reference beam; and (E) sensing a reference interference pattern between the first portion of the reference beam and the second portion of the reference beam, the reference interference pattern representing a position of the first optical element with respect to the second optical element. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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26. An imaging spectrometer comprising:
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a beamsplitter, to split light from an object into a first object beam and a second object beam; at least one optical element, in optical communication with the beamsplitter, to delay the first object beam with respect to the second object beam by a plurality of delay periods; at least one actuator, in mechanical communication with the at least one optical element, to move the at least one optical element to each of a plurality of positions so as to produce the plurality of delay periods, the at least one actuator being further configured to tip and/or tilt the at least one optical element; a detector array, in optical communication with the at least one optical element, to sense a plurality of interference periods, the plurality of interference periods comprising at least one interference pattern between the first object beam and the second object beam at each delay period in the plurality of delay periods; and a processor, operably coupled to the detector array, to determine a spectroscopic image of the object based at least in part on the plurality of interference patterns and to determine at least one position in the plurality of positions based at least in part on the spectroscopic image and a transfer function of the at least one actuator. - View Dependent Claims (27)
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Specification