The New York Police Department is developing a new way to seek people toting guns on the street with radiation scanners that can detect those packing heat, says the New York Daily News. The technology, which works like infrared imaging, includes a mechanism that can detect a natural energy, known as terahertz radiation, that emits from a person's body, said Police Commissioner Raymond Kelly.
Because the radiation waves cannot travel through metal, a concealed gun can be detected from the image captured by the lens of the detector, Kelly said. “This technology has shown a great deal of promise as a way of detecting weapons without a physical search,” he said. However, the technology, which has been undergoing testing for three years, can be used only at a distance of 3 to 4 feet. Civil liberties lawyer Norman Siegel said he hopes the scanning devices will be able to distinguish between a gun and other harmless metal objects, such as an iPod.