As the U.S. gun control debate continues in full force, several authorities are looking for ways to catch people illegally possessing firearms.

The New York Police Department announced today that it will soon adopt portable scanning technology that lets police officers see from a distance whether someone is carrying a concealed weapon, according to the New York Daily News.

The scanner is a device small enough to fit in a police van or set up on a street corner that reads terahertz radiation, which is energy emitted by both humans and inanimate objects. When aimed at a person, it's possible to see anything that is blocking the specific energy coming off the human -- such as a gun.

"If something is obstructing the flow of that radiation, for example a weapon, the device will highlight that object," Police Commissioner Raymond Kelly said, according to the New York Daily News.

Using terahertz machines has been the subject of controversy among civil liberties groups. Not only can authorities "search" individuals without cause, but false positives can also lead to unjustified stops.

The NYPD said it hopes to start testing the device in high-crime areas in the near future, according to the New York Daily News.

"We still have a number of trials to run before we can determine how best to deploy this technology," Kelly said. "We're also talking to our legal staff about this. But we're very pleased with the progress we've made over the past year."