Micro-spectral sensor
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsMichael Wilson, Thomas G Giallorenzi
Life of this patent
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Abstract
Micro-spectral sensors and methods are presented in which a Fizeau wedge interference filter is disposed between a focal plane array and a visible scene with an increasing wedge filter dimension varying along a scan direction, where the scene is scanned along the FPA to obtain light intensity measurements of a given scene location at different times using different FPA sensor elements through different wedge filter thicknesses, and the measurements correlated to the given scene location are Fourier transform to generate spectral data for the location.
Claims18
A micro-spectral sensor, comprising:
- a focal plane array (FPA) having a plurality of sensor elements with sensing faces formed in a two-dimensional array in a focal plane;
- a wedge interference filter, comprising:
- a first side extending between first and second opposite ends in a first plane generally parallel with the focal plane of the FPA,
- a second side extending between a first end proximate the first end of the first side and a second end proximate to and spaced from the second end of the first side, the second side disposed in a second plane at a nonzero angle relative to the first plane of the first side, the first side extending between the second side and the FPA;
- a lens directing incoming light from a scanned scene toward the FPA through the first and second sides of the wedge interference filter;
- an electronic memory;
- and
- a processor operatively coupled with the FPA and the memory to:
- obtain a plurality of intensity measurement values from the FPA for each of a plurality of sample periods as a scene is scanned across at least a portion of the FPA along a scan direction generally parallel to a line extending between the first and second opposite ends of the first side,
- store the plurality of intensity measurement values in the electronic memory,
- correlate intensity measurement values from multiple sensor elements of the FPA obtained at different sample periods with at least one specific scene location, and
- perform a Fourier transform using intensity measurement values corresponding to the at least one specific scene location to generate spectral data for the at least one specific scene location.
A method of generating spectral data for a scanned scene, the method comprising:
- scanning a scene in a scan direction across at least a portion of a focal plane array (FPA) to direct incoming light from the scene toward the FPA through a wedge interference filter having a thickness that changes along the scan direction;
- obtaining a plurality of intensity measurement values from the FPA for each of a plurality of sample periods as the scene is scanned across the portion of the FPA;
- correlating intensity measurement values from multiple sensor elements of the FPA obtained at different sample periods with at least one specific scene location;
- performing a Fourier transform using intensity measurement values corresponding to the at least one specific scene location;
- and
- generating spectral data for the at least one specific scene location of the scene.
Dependencies are inferred from the claim text.