Warm filter configuration for reducing effects of reflected infrared radiation systems and methods
AssigneeFLIR Systems, Inc.
InventorsSten Lindau, Austin A. Richards
Life of this patent
Estimating the term…
Abstract
Various techniques are disclosed to reduce the effect of reflected infrared radiation on cooled thermal imaging systems. In one example, a system includes an integrated dewar cooler assembly (IDCA) configured to maintain an interior volume at a constant temperature. The system also includes a thermal imager disposed within the interior volume and configured to capture thermal images. The system also includes an optical element external to the IDCA and configured to provide reflected infrared radiation in a uniform distribution over a field of view of the thermal imager in response to emitted infrared radiation from the thermal imager. Additional methods, devices, and systems are also provided.
Claims20
A system comprising:
- an integrated dewar cooler assembly (IDCA) configured to maintain an interior volume at a constant temperature;
- a thermal imager disposed within the interior volume and configured to capture thermal images;
- and
- an optical element external to the IDCA and configured to provide reflected infrared radiation in response to emitted infrared radiation from the thermal imager;
- wherein the IDCA further comprises a coldshield comprising a coldstop configured to define the interior volume and a field of view of the thermal imager;
- and
- wherein for each sensor of the thermal imager, within a solid angle viewed by the sensor through the coldstop, any ray reflected by the optical element returns back to the thermal imager through the coldstop;
- wherein rays emitted by the thermal imager within the field of view of the thermal imager and reflected and provided by the optical element are received by the thermal imager.
A system comprising:
- an integrated dewar cooler assembly (IDCA) configured to maintain an interior volume at a constant temperature;
- a thermal imager disposed within the interior volume and configured to capture thermal images;
- and
- a lens external to the IDCA and configured to provide reflected infrared radiation in response to emitted infrared radiation from the thermal imager;
- wherein:
- the IDCA comprises a coldshield comprising a coldstop configured to define the interior volume and a field of view of the thermal imager;
- the system further comprises a filter external to the IDCA and configured to pass filtered infrared radiation from an external scene to the lens;
- the lens is configured to pass the filtered infrared radiation to the thermal imager to be captured in the thermal images;
- the filter comprises a flat surface facing the lens and configured to reflect the emitted infrared radiation to provide the reflected infrared radiation to the lens;
- and
- corner rays emitted by a corner portion of the thermal imager pass through the lens and are reflected by the flat surface of the filter to provide reflected rays that pass back through the lens toward the thermal imager and are shaped by the lens to provide a uniform distribution over the thermal imager.
A method comprising:
- operating an integrated dewar cooler assembly (IDCA) of an imaging system to maintain an interior volume at a constant temperature, wherein the IDCA comprises a coldshield comprising a coldstop configured to define the interior volume and a field of view of the thermal imager;
- operating a thermal imager disposed within the interior volume to capture thermal images;
- and
- providing, by an optical element external to the IDCA, reflected infrared radiation in a uniform distribution over a field of view of the thermal imager in response to emitted infrared radiation from the thermal imager;
- wherein for each sensor of the thermal imager, within a solid angle viewed by the sensor through the coldstop, any ray in the reflected infrared radiation returns back to the thermal imager through the coldstop;
- wherein the interior volume and the field of view of the thermal imager are defined by the coldstop of the coldshield disposed within the IDCA;
- and
- wherein the thermal imager does not receive extraneous infrared radiation emitted by portions of the imaging system external to the coldshield.
Dependencies are inferred from the claim text.