U.S. soldiers performing dark, dangerous worklike searching Afghanistan's cavesmay soon benefit from the smallest-ever infrared cameras unveiled this week at the International Society for Optical Engineering in Orlando, FL.

The camerasSanta-Barbara, CA-based Indigo Systems' Omega and Costa Mesa, CA-based Irvine Sensors Corporation's Cam-Noirare rivals to the claim of the world's smallest infrared camera. Each measures a few centimeters on a sidesmall enough to fit in a heads-up-display worn by, say, a soldier or firefighter. And unlike most infrared cameras, which take time to adjust to their environment, the new generation turns on instantly.

"It's revolutionary," says Roy Malmberg, an Indigo engineer. "You put it in your hand and say 'holy smokeslook at how tiny that is.'"

Infraredalso known as thermalcameras detect the heat radiated from objects. Most modern thermal cameras rely on a sensor called a microbolometer that absorbs heat from its environment. A microprocessor converts the microbolometer's measurements into a black-and-white picture, which the cameras can transmit to either a remote viewer or an attached display. Unlike night-vision goggles, which amplify low levels of light, thermal cameras can function in complete darkness. That makes them especially useful indoors, underground and in occluded-vision situations, such as a smoky fire.

Traditionally, microbolometer cameras had to operate at a specific temperature, which required an internal heating or cooling device. This so-called "thermostabilization" not only added weight, but also created a delay as the camera warms up, according to Irvine Sensors chief technical officer John Carson.

"We took an entirely different approach," says Irvine vice president John Stuart. Instead of cooling their camera to a specific temperature, researchers at the company calibrated its sensors to a wide range of temperatures, "from arctic to desert," he says. The camera stores the settings in a memory chip and selects the best one using a thermometera smaller, faster solution that allows the camera to take pictures as soon as it is turned on.

"That kind of instant-on capability opens up a lot of field applications that weren't before possible," Stuart says. Examples include remote cameras activated by the noise or vibration of passing vehicles, gun-sight cameras ready at the flick of a switch and night-vision headgear that allow soldiers to see in complete darkness.

Research at both firms was funded by the Defense Advanced Projects Research Agency and the U.S. Army's Night Vision Laboratory. While the U.S. military will be the first customer, both companies intend to target civilian customers, including fire departments, security services, and eventually automobiles (Virginia firefighters used infrared cameras in the aftermath of the terrorist attack on the Pentagon; the 2000 Cadillac Deville was the first automobile to incorporate them).

Irvine Sensors' long-range goal, Carson says, is to incorporate image recognition into their cameras. "There's a revolution underway in intelligent machines," he says. And a camera that knows what it's looking at may one day protect soldiers by keeping them from ever having to go into a cave in the first place.