Wide field of view imaging systems and methods
Techniques for facilitating wide field of view (FOV) imaging systems and methods are provided. In one example, an imaging device includes a lens system including a first lens group and a second lens group. The first lens group includes at least one spherical lens element and is associated with a first FOV. The first lens group is configured to transmit electromagnetic radiation associated with a scene. The second lens group includes wafer level optics aspherical lens elements and is associated with a second FOV narrower than the first FOV. The second lens group is configured to transmit the electromagnetic radiation received from the first lens group. The imaging device further includes a detector array including detectors. Each detector is configured to receive a portion of 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 lens system comprising:
a first lens comprises a first spherical surface and a second spherical surface opposite the first spherical surface, wherein the first lens is configured to transmit electromagnetic radiation associated with a scene, wherein the first lens is associated with a first field of view;
a second lens comprises a first wafer level optics (WLO) aspherical lens element, wherein the second lens is configured to receive the electromagnetic radiation from the first lens and transmit the electromagnetic radiation, and wherein the second lens is spaced apart from the first lens by a first lens-free gap; and
a third lens comprises a second WLO aspherical lens element, wherein the third lens is configured to receive the electromagnetic radiation from the second lens and transmit the electromagnetic radiation, wherein the third lens is spaced apart from the second lens by a second lens-free gap, and wherein the second lens and the third lens are collectively associated with a second field of view narrower than the first field of view;
a window configured to receive the electromagnetic radiation from the third lens and transmit the electromagnetic radiation, wherein the window is spaced apart from the third lens by a third lens-free gap; and
a detector array comprising a plurality of detectors, wherein the detector array is spaced apart from the window by a fourth lens-free gap, and wherein each of the plurality of detectors is configured to receive a portion of the electromagnetic radiation from the lens system and generate a thermal image based on the received portion of the electromagnetic radiation.
2. The imaging device of claim 1 , wherein the first field of view is between around 110° and around 220°.
3. The imaging device of claim 2 , wherein the first field of view is between around 120° and around 160°.
4. The imaging device of claim 2 , wherein the second field of view is between around 50° and around 70°.
5. The imaging device of claim 1 , further comprising a shutter configured to be selectively inserted between the first lens and the second lens.
6. The imaging device of claim 1 , further comprising:
a lens barrel configured to receive the first lens, the second lens, and the third lens; and
a housing, wherein the lens barrel is coupled to the housing.
7. The imaging device of claim 6 , wherein the lens barrel comprises:
a first lens barrel portion configured to receive the first lens; and
a second lens barrel portion configured to couple to the first lens barrel portion and receive the second and third lenses.
8. The imaging device of claim 1 , wherein the electromagnetic radiation comprises long-wave infrared light.
9. The imaging device of claim 1 , further comprising:
a logic device configured to process the thermal image to obtain a processed image; and
a display device configured to display the thermal image and/or the processed image, wherein the detector array comprises an array of microbolometers.
10. A method of manufacturing the imaging device of claim 1 , the method comprising:
providing the detector array;
disposing the detector array within a housing;
disposing the second and third lenses within a first portion of a lens barrel;
coupling the first portion of the lens barrel to the housing;
performing a calibration of the second and third lenses to obtain a gain map;
disposing the first lens within a second portion of the lens barrel; and
after the calibration, coupling the second portion of the lens barrel to the first portion of the lens barrel.
11. The method of claim 10 , further comprising:
forming the second and third lenses using one or more WLO manufacturing processes; and/or
forming the first lens using one or more grinding processes and/or one or more polishing processes.
12. The method of claim 10 , wherein the first field of view is between around 110° and around 220°.
13. The method of claim 10 , wherein the performing the calibration comprises:
positioning a reference object in the second field of view;
capturing, using the second and third lenses, image data of the reference object; and
determining the gain map based on the image data.
14. The method of claim 10 , further comprising:
positioning a front lens element in the second field of view;
focusing the front lens element and the second and third lenses relative to the detector array; and
removing the front lens element,
wherein the calibration is performed after the removing and with the second and third lenses positioned according to the focusing.
15. The imaging device of claim 1 , wherein the second WLO aspherical lens element has a planar surface facing the detector array.
16. The imaging device of claim 15 , wherein the second WLO aspherical lens element has a convex surface opposite the planar surface.
17. The imaging device of claim 1 , wherein the first WLO aspherical lens element is a plano-convex lens element having a planar surface facing the second spherical surface and a convex surface opposite the planar surface.
18. A method comprising:
directing, by a window and a lens system comprising a first lens, a second lens, and a third lens, electromagnetic radiation associated with a scene to a detector array, wherein the first lens is associated with a first field of view and comprises a first spherical surface and a second spherical surface opposite the first spherical surface, wherein the second lens comprises a first wafer level optics (WLO) aspherical lens element, wherein the third lens comprises a second WLO aspherical lens element, wherein the second lens and the third lens are collectively associated with a second field of view narrower than the first field of view, wherein the second lens is spaced apart from the first lens by a first lens-free gap, wherein the third lens is spaced apart from the second lens by a second lens-free gap, and wherein the window is spaced apart from the third lens by a third lens-free gap;
receiving, by the detector array, the electromagnetic radiation from the lens system, wherein the detector array is spaced apart from the window by a fourth lens-free gap; and
generating, by the detector array, a thermal image based on the received electromagnetic radiation and a gain map, wherein the gain map is based on a collective calibration of the second and third lenses.
19. The method of claim 18 , wherein the directing comprises:
directing, by the first lens, the electromagnetic radiation to the second lens;
directing, by the second lens, the electromagnetic radiation to the third lens;
directing, by the third lens, the electromagnetic radiation to the window; and
directing, by the window, the electromagnetic radiation to the detector array, wherein the gain map is based on the calibration of the second and third lenses by inserting a shutter between the first lens and the second lens.
20. The method of claim 18 , further comprising displaying, by a display device, the thermal image, wherein the electromagnetic radiation comprises long-wave infrared light, and wherein the first field of view is between around 110° and around 220°.