Breakthrough in thermal imagers means they can be smaller than ever before
Camera can peer through particles in the air, which would be useful for helicopters landing in brownout conditions
Long-wave infrared (LWIR) cameras are used as thermal imagers to detect people at night, and are typically mounted on vehicles because they are too large to be carried by a single warfighter and are too expensive for individual deployment. However, researchers at the Defense Advanced Research Projects Agency and DRS Technologies recently demonstrated a new five-micron pixel LWIR camera that could make this class of camera smaller and less expensive.
Working as part of the DARPA Advanced Wide FOV Architectures for Image Reconstruction and Exploitation (AWARE) program, DARPA and DRS demonstrated the first LWIR camera that uses pixels only five microns across.
“This is the first IR camera with pixels about half the size of the photons it detects,” stated an article on the DARPA website. “For comparison, each pixel is about one twelfth the size of a human hair, or about one-sixth the area of current state of the art. The pixels are configured in a 1280x720 focal plane array (FPA)—a relatively high resolution for an IR camera.”
DARPA program manager Nibir Dhar said this in the article: “DRS built three fully functional prototypes as part of this DARPA work. The cameras have been tested for various applications, including peering through particles in the air, which would be useful for helicopters landing in brownout conditions. We have found that the image is crisp and the performance of these FPAs is comparable to those with much larger pixel sizes.”
DARPA compares the development of smaller pixels for LWIR cameras to those used in cellphone camera.
“Smaller pixels mean smaller optical components and packaging without forfeiting sensitivity, resolution or field of view,” states DARPA. “A higher density of pixels over a given area makes it easier to capture the photons from, and thus image, a target. The cumulative result is a smaller, lighter and more portable LWIR camera.”
These new LWIR cameras may also be less expensive than current sensors because the cost of FPAs is proportional to chip area. FPAs are processed on a given wafer size. The more FPAs that can be printed on a single wafer, the lower the cost per FPA. Smaller pixels will therefore reduce the size, weight, power and cost.