Offset compensation scheduling algorithm for infrared imagers
First Claim
Patent Images
1. A method of scheduling offset compensation for an infrared (IR) imaging apparatus comprising:
- a) temporarily providing one or more generally uniform IR energy scenes onto a focal plane array (FPA) of the IR imaging apparatus, the FPA comprising a plurality of IR detector elements, each provision of the generally uniform IR energy scene being part of an offset compensation routine;
b) measuring one or more outputs of the FPA from each of the one or more generally uniform IR energy scenes over time;
c) determining a FPA output drift based on two or more of the FPA outputs; and
d) scheduling a next offset compensation routine based on the drift.
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Abstract
A method of scheduling offset compensation for an infrared (IR) imaging system to maintain good image quality. The method includes a scheduling algorithm for automatic offset compensation. The scheduling algorithm automatically adjusts periods between offset compensations based on the measurement of drift of the focal plane array (FPA) pixel levels. As a result, the periods are adjusted both when the camera is thermally stable and when the camera is undergoing an internal thermal change.
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Citations
29 Claims
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1. A method of scheduling offset compensation for an infrared (IR) imaging apparatus comprising:
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a) temporarily providing one or more generally uniform IR energy scenes onto a focal plane array (FPA) of the IR imaging apparatus, the FPA comprising a plurality of IR detector elements, each provision of the generally uniform IR energy scene being part of an offset compensation routine; b) measuring one or more outputs of the FPA from each of the one or more generally uniform IR energy scenes over time; c) determining a FPA output drift based on two or more of the FPA outputs; and d) scheduling a next offset compensation routine based on the drift. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A computer-readable medium programmed with instructions for scheduling offset compensation for an infrared (IR) imaging system, the medium comprising instructions for causing a programmable processor to:
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a) receive measurements of one or more outputs of a focal plane array (FPA) temporarily exposed to one or more generally uniform IR energy scenes over time, the FPA comprising a plurality of IR detector elements, each exposure of the generally uniform IR energy scene being part of an offset compensation routine; b) determine an FPA output drift based on two or more of the FPA outputs; and c) schedule a next offset compensation routine based on the drift. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. An infrared (IR) imaging apparatus comprising:
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a lens for focusing IR energy from a target scene; a focal plane array (FPA) paired with the lens adapted to receive the IR energy from the target scene via the lens, the FPA comprising a plurality of IR detector elements; means for temporarily exposing the FPA to one or more generally uniform IR energy scenes, each exposure of the generally uniform IR energy scene being part of an offset compensation routine; a processor operatively coupled to the FPA and for receiving measurements of one or more outputs of the FPA corresponding to each of the one or more generally uniform IR energy scenes over time, the processor determining an FPA output drift of two or more of the FPA outputs over time, and the processor using the drift to predict when the change in output of the FPA should equal a predetermined threshold change in the output of the FPA and scheduling a next offset compensation routine based on the prediction. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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Specification