NEWARK, N.J. — Newark Liberty International Airport became the first New York-area airport to install body scanning technology that will replace a system that was harshly criticized for invading travelers’ privacy by displaying naked images.

Transportation Security Administration officials u

nveiled the software at the airport on Friday, where more than 8 million passengers boarded planes last year. The technology was originally tested in February at Atlanta, Las Vegas, and Washington, D.C., and rolled out in July.

In all, the technology will be installed in 241 security machines at 40 airports around the country over the next few months at a cost of $2.7 million that includes research and development, according to the TSA. The agency plans to install it in all airports eventually.

The new system uses a screen that displays a gray silhouette of a generic body. The screen is placed at security checkpoints in a spot where both the traveler and the security agent can see it.

In demonstrations Friday using TSA employees as travelers, yellow boxes appeared on the silhouette denoting items that needed to be removed such as cellphones or keys.

Under the previous system, the images of travelers’ bodies were displayed in a separate room, where a TSA officer would radio the officer at the checkpoint that a traveler was carrying an item that needed to be scanned. The new system speeds that process by using the yellow boxes to display the exact locations of the offending items, according to Donald Drummer, the airport’s federal security director.

“In the past there was an image viewing room that was remote that looked at a body-specific image,” Drummer said. “In this case we will have a silhouette on the screen that both the passenger and our officer will see and they will know where to target.”

TSA employees currently assigned to image viewing rooms will be shifted to other positions within the agency, a TSA spokeswoman said.

The body scanners’ debuted last fall sparked a heated debate over security concerns versus travelers’ privacy.

Some called the scans — and the enhanced pat-downs given to people who opted not to be scanned — violations of the Fourth Amendment right against unreasonable searches. The system also created concerns that the naked images could be downloaded and distributed.

According to TSA statistics, about 2 percent of travelers have opted out of the scans and submitted to pat-downs. The new, generic body scans could lower that number, though some travelers may opt out due to concerns over exposure to radiation.

Deborah Jacobs, executive director of ACLU New Jersey, which also has been critical of the security procedures, said privacy concerns remain for people who use colostomy bags or wear adult diapers, for instance. She also said it was unclear whether the nude images already taken of travelers are accessible to TSA employees.