Criminals in the Dallas area who rely on the cover of night are no match for local law enforcement's latest weapon. The US Department of Transportation and the Texas Transportation Institute recently employed Raytheon TI Systems' NightSight infrared camera system as part of the ALERT project, a state-of-the-art police communications system. This camera system detects infrared heat, so officers can "see" criminals in the dark.Infrared technology shines a new light on criminals. Police use the mounted IR camera systems in helicopters and on cars, as well as the handheld versions, in fugitive apprehension, search and rescue, vehicle pursuit, building surveillance and other applications. "The car-top systems were a very pleasant surprise," said Charlie Stowell of the Law Enforcement Thermographers Association, who trained Dallas officers on the system. "It allowed for several applications and enhanced officer safety."Stowell was impressed with the Raytheon TI system's flexibility. "Any IR imaging camera turns night into day," he explained. "This system has the versatility to enable several new applications."The imagers detect radiation in the 7.5- to 13.5-µm range, which is the spectrum emitted by people and terrestrial objects. The system measures small temperature differences to create images that the human eye cannot see.Thermal image arrays detect radiation by focusing energy on about 80,000 tiny detectors, which process and display the electronic signals on a standard video monitor. By translating emitted heat energy into a visible image, thermal imaging heightens a user's perception level. It uses a solid-state thermoelectric cooler from Dallas-based Marlowe Industries Inc. to stabilize the detector's temperature.Officers in nearby McKinney, Texas, find the infrared system most valuable for surveillance. For example, NightSight can show officers if parked cars are warm at 2 a.m., indicating recent use, or which section of a building they need not search if the system shows that part of the building is "cold."The camera's use in military technology is an asset to McKinney law enforcement. "We want to see policing get that same technology," said Police Chief Larry Robinson. "We're fighting on the streets in this country." The NightSight infrared system is also valuable in asset seizures. "For asset-seizure cases, these cameras are bringing in the bucks," Stowell said. "These instruments are not a burden on taxpayers."