Window obscuration sensors for mobile gas and chemical imaging cameras
First Claim
1. An infrared (IR) imaging system comprising:
- a housing;
an optical window disposed on the housing;
an optical detector system disposed within the housing; and
a plurality of spatially and spectrally distinct optical channels that transfer incident IR radiation from the optical window to the optical detector system, wherein a first optical channel out of the plurality of optical channels has a focus distance that is closer to the optical window than at least some of the other optical channels of the plurality of optical channels to detect obscuration that may degrade operation of the system.
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Abstract
An infrared (IR) imaging system for determining a concentration of a target species in an object is disclosed. The imaging system can include an optical system including a focal plane array (FPA) unit behind an optical window. The optical system can have components defining at least two optical channels thereof, said at least two optical channels being spatially and spectrally different from one another. Each of the at least two optical channels can be positioned to transfer IR radiation incident on the optical system towards the optical FPA. The system can include a processing unit containing a processor that can be configured to acquire multispectral optical data representing said target species from the IR radiation received at the optical FPA. One or more of the optical channels may be used in detecting objects on or near the optical window, to avoid false detections of said target species.
169 Citations
19 Claims
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1. An infrared (IR) imaging system comprising:
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a housing; an optical window disposed on the housing; an optical detector system disposed within the housing; and a plurality of spatially and spectrally distinct optical channels that transfer incident IR radiation from the optical window to the optical detector system, wherein a first optical channel out of the plurality of optical channels has a focus distance that is closer to the optical window than at least some of the other optical channels of the plurality of optical channels to detect obscuration that may degrade operation of the system. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An infrared (IR) imaging system for imaging a target species in a scene, the IR imaging system comprising:
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an optical window; a first camera system configured to acquire infrared image data of the scene through the optical window; a second camera system focused closer to the optical window than the first camera system; and a processing unit containing a processor configured to; analyze the infrared image data from the first camera system to detect the target species based on the infrared image data; and analyze image data from the second camera system to determine whether obscuration is present that may degrade operation of the system based on the image data from the second camera system. - View Dependent Claims (9, 10, 11)
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12. A method of detecting obscuration of an optical window in an IR imaging system, the IR imaging system comprising processing circuitry and a plurality of spatially and spectrally distinct optical channels, each optical channel including a set of lenses that focus incident IR light on a respective portion of an optical detector system, the method comprising:
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with the processing circuitry, receiving a first image from a first optical channel in the plurality of optical channels; with the processing circuitry, receiving a second image from a second optical channel in the plurality of optical channels; and with the processing circuitry, analyzing the first and second images to detect obscuration that may degrade operation of the system, said analyzing comprising; creating first and second gradient images from the first and second images, respectively; cross-correlating the first and second gradient images; and determining that at least one cross-correlation between the first and second gradient images exceeds a first window obscuration threshold and that the first and second gradient images exceed a second window obscuration threshold and, in response, providing an alert that the optical window is obscured. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification