Thermal imaging system and method using scene-average radiation as a thermal reference
First Claim
1. A DCR method, used in a thermal imaging system with an optical path that includes an array of thermal image detectors, for providing a passive source of thermal reference radiation to the thermal image detector array;
- comprising the steps;
during selected DCR intervals, redirecting the optical path for the thermal imaging system to include a DCR imaging path such that a redirected optical bundle is introduced into the DCR imaging path as a DCR imaging bundle; and
in the DCR imaging path, performing optical operations on the DCR imaging bundle and then reintroducing the DCR imaging bundle back into the optical path of the thermal imaging system to form a pupil onto an image of a thermal scene;
such that scene-average radiation is provided to the thermal image detector array as a thermal reference.
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Accused Products
Abstract
A pupil/image reversal prism (FIG. 2) forms a pupil at an image location. Such a prism has specific applicability in a DCR scheme for a thermal imaging system (FIG. 3a, 31 and 32) in which a passive DCR source is implemented by a pupil imager that forms a pupil onto the image of a thermal scene, thereby providing scene-average radiation to a thermal detector array. The pupil/image reversal prism including an input reflective surface (A), an output reflective surface (B), a positive reflective surface (C) and an intermediate folding reflective surface (D). The reflective surfaces A and B use total internal reflection to provide both transmissive and reflective operation.
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Citations
19 Claims
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1. A DCR method, used in a thermal imaging system with an optical path that includes an array of thermal image detectors, for providing a passive source of thermal reference radiation to the thermal image detector array;
- comprising the steps;
during selected DCR intervals, redirecting the optical path for the thermal imaging system to include a DCR imaging path such that a redirected optical bundle is introduced into the DCR imaging path as a DCR imaging bundle; and in the DCR imaging path, performing optical operations on the DCR imaging bundle and then reintroducing the DCR imaging bundle back into the optical path of the thermal imaging system to form a pupil onto an image of a thermal scene; such that scene-average radiation is provided to the thermal image detector array as a thermal reference. - View Dependent Claims (2, 3, 4, 15, 16)
- comprising the steps;
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5. A thermal imaging system including DCR pupil imaging optics for providing a passive DCR thermal reference source, comprising:
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a thermal detector array; imaging optics for imaging a thermal scene onto said detector array; and DCR pupil imaging optics for forming a pupil on an image of the scene, such that the detector receives scene-average radiation as a thermal reference; during selected DCR intervals, said imaging optics redirects the optical path for the detector array to include the DCR pupil imaging optics. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 17, 18, 19)
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Specification