CHICAGO (AP) — The federal government is quietly removing full-body X-ray scanners from seven major airports and replacing them with a different type of machine that produces a cartoon-like outline instead of the naked images that have been compared to a virtual strip search.

The Transportation Security Administration says it is making the switch in technology to speed up lines at crowded airports, not to ease passenger privacy concerns. But civil liberties groups hope the change signals that the equipment will eventually go to the scrap heap.

“Hopefully this represents the beginning of a phase-out of the X-ray-type scanners, which are more privacy intrusive and continue to be surrounded by health questions,” said Jay Stanley, a privacy expert at the American Civil Liberties Union.