Imager optical systems and methods
Imager optical systems and methods are provided. In one example, an imaging device includes a window configured to transmit electromagnetic radiation associated with a scene. The imaging device further includes a lens system. The lens system includes a first lens element configured to receive the electromagnetic radiation from the window and transmit the electromagnetic radiation. An aperture stop is positioned between the window and a surface of the first lens element adjacent to the window. The lens system further includes a second lens element adjacent to the first lens element and configured to receive the electromagnetic radiation and direct the electromagnetic radiation to the detector array. The imaging device further includes a detector array including detectors. Each detector is configured to receive the electromagnetic radiation from the lens system and generate a thermal image based on the electromagnetic radiation. Related methods and systems are also provided.
1. An imaging device comprising:
a window configured to transmit electromagnetic radiation associated with a scene;
a lens system comprising:
a first lens element configured to receive the electromagnetic radiation from the window and transmit the electromagnetic radiation, wherein the first lens element comprises a first concave surface and a first convex surface opposite the first concave surface, wherein the first concave surface is adjacent to and facing the window, and wherein an aperture stop is positioned between the window and the first concave surface of the first lens element; and
a second lens element adjacent to the first lens element and configured to receive the electromagnetic radiation and transmit the electromagnetic radiation; and
a detector array comprising a plurality of detectors, wherein each of the plurality of detectors is configured to receive the electromagnetic radiation from the lens system and generate a thermal image based on the electromagnetic radiation.
2. The imaging device of claim 1 , further comprising a lens barrel configured to receive the window, the first lens element, and the second lens element, wherein the second lens element comprises a second concave surface and a second convex surface opposite the second concave surface, and wherein the second concave surface faces the first convex surface of the first lens element.
3. The imaging device of claim 1 , further comprising one or more coatings disposed on the first lens element and/or the second lens element, wherein each of the one or more coatings is an anti-reflective coating, a filter coating, and/or a polarization coating.
4. The imaging device of claim 1 , further comprising a third lens element adjacent to the second lens element and configured to receive the electromagnetic radiation from the second lens element and direct the electromagnetic radiation to the detector array.
5. The imaging device of claim 4 , further comprising a lens barrel configured to receive the window, the first lens element, the second lens element, and the third lens element, wherein the first lens element, the second lens element, and the third lens element are the only lens elements disposed between the window and the detector array.
6. The imaging device of claim 5 , further comprising a housing, wherein the lens barrel is coupled to the housing.
7. The imaging device of claim 2 , wherein:
the second convex surface of the second lens element faces the detector array; and
the first lens element and the second lens element are the only lens elements disposed between the window and the detector array.
8. The imaging device of claim 1 , wherein a surface of the window faces the scene, and wherein the first lens element and the second lens element are associated with parameters according to Table 1.
9. The imaging device of claim 1 , wherein the electromagnetic radiation comprises mid-wave infrared light and/or long-wave infrared light.
10. The imaging device of claim 1 , further comprising a processor configured to process the thermal image to obtain a processed image, wherein the detector array comprises an array of microbolometers, and wherein the window comprises silicon and/or zinc blende.
11. A method of manufacturing the imaging device of claim 1 , the method comprising:
providing the detector array;
disposing the first and second lens elements at least partially within a lens barrel of the imaging device;
disposing the window at least partially within the lens barrel; and
disposing the detector array within a housing.
12. A method of manufacturing the imaging device of claim 1 , the method comprising performing calibration in relation to an optical path including the window, the first lens element, the second lens element, and the detector array.
13. A vehicle comprising the imaging device of claim 1 , wherein the imaging device is configured to be replaceable with a manufacturer calibrated imaging device and usable without recalibration.
14. A method for providing imaging functionality to a vehicle comprising the imaging device of claim 1 , the method comprising:
mounting the imaging device onto the vehicle;
operating the imaging device to generate thermal images;
replacing the imaging device with a manufacturer calibrated imaging device usable without recalibration.
15. A method comprising:
transmitting, by a window, electromagnetic radiation associated with a scene;
directing, by a lens system comprising a first lens element adjacent to the window and a second lens element adjacent to the first lens element, the electromagnetic radiation to a detector array, wherein the first lens element comprises a first concave surface and a first convex surface opposite the first concave surface, wherein the first concave surface is adjacent to and facing the window, and wherein an aperture stop is positioned between the window and the first concave surface of the first lens element;
receiving, by the detector array, the electromagnetic radiation; and
generating, by the detector array, a thermal image based on the electromagnetic radiation.
16. The method of claim 15 , wherein the directing comprises:
directing, by the first lens element, the electromagnetic radiation from the window to the second lens element; and
directing, by the second lens element, the electromagnetic radiation to the detector array, wherein the second lens element comprises a second concave surface and a second convex surface opposite the second concave surface, and wherein the second concave surface faces the first convex surface of the first lens element.
17. The method of claim 15 , wherein the directing further comprises directing, by a third lens element of the lens system, the electromagnetic radiation from the second lens element to the detector array.
18. The method of claim 17 , wherein the directing further comprises directing, by a fourth lens element of the lens system, the electromagnetic radiation from the third lens element to the detector array, and wherein the electromagnetic radiation comprises mid-wave infrared light and/or long-wave infrared light.
19. The imaging device of claim 2 , wherein a curvature associated with the second concave surface is substantially equal to a curvature associated with the second convex surface.
20. The imaging device of claim 19 , wherein the curvature associated with the second concave surface of the second lens element is substantially equal to a curvature associated with the first convex surface of the first lens element.