NYPD Commissioner Raymond W. Kelly said the new technology can reveal a firearm concealed under clothing, the New York Daily News reported Wednesday.
The technology, similar to infrared imaging, can detect a natural energy known as terahertz radiation emitted by the human body, Kelly said during his State of the NYPD address Tuesday.
Because that energy cannot travel through metal, a concealed gun can be detected from the image captured by 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.
The technology has been undergoing testing by the NYPD and the U.S. Department of Defense for the past three years.
The NYPD hopes to install the heat-seeking devices on police vehicles in the near future, Kelly said.
"We want to use new technology to protect the public and police officers from illegal guns," he said.
But civil libertarians say they worry the scanning devices will be unable to distinguish between a gun and other harmless metal objects such as an iPod.
If the technology only picks up only fuzzy images of possible guns, civil liberties lawyer Norman Siegel said, it could prompt police to make unwarranted stops.
"It will make an already aggressive policy of stop, question and frisk seem tame," he said.