BALTIMORE (AP) — A passenger walks up to an airport security checkpoint, slips an ID card into a slot and looks into a camera atop a small screen. The screen flashes “Photo Complete” and the person walks through — all without having to hand over their identification to the TSA officer sitting behind the screen.

It’s all part of a pilot project by the Transportation Security Administration to assess the use of facial recognition technology at a number of airports across the country.

“What we are trying to do with this is aid the officers to actually determine that you are who you say who you are,” said Jason Lim, identity management capabilities manager, during a demonstration of the technology to reporters at Baltimore-Washington International Thurgood Marshall Airport.

The effort comes at a time when the use of various forms of technology to enhance security and streamline procedures is only increasing. TSA says the pilot is voluntary and accurate, but critics have raised concerns about questions of bias in facial recognition technology and possible repercussions for passengers who want to opt out.

The technology is currently in 16 airports. In addition to Baltimore, it’s being used at Reagan National near Washington, DC, airports in Atlanta, Boston, Dallas, Denver, Detroit, Las Vegas, Los Angeles, Miami, Orlando, Phoenix, Salt Lake City, San Jose, and Gulfport-Biloxi and Jackson in Mississippi. However, it’s not at every TSA checkpoint so not every traveller going through those airports would necessarily experience it.

Travellers put their driver’s license into a slot that reads the card or place their passport photo against a card reader. Then they look at a camera on a screen about the size of an iPad, which captures their image and compares it to their ID. The technology is both checking to make sure the people at the airport match the ID they present and that the identification is in fact real. A TSA officer is still there and signs off on the screening.

A small sign alerts travellers that their photo will be taken as part of the pilot and that they can opt out if they’d like. It also includes a QR code for them to get more information.

Since it’s come out the pilot has come under scrutiny by some elected officials and privacy advocates. In a February letter to TSA, five senators — four Democrats and an Independent who is part of the Democratic caucus — demanded the agency stop the program, saying: “Increasing biometric surveillance of Americans by the government represents a risk to civil liberties and privacy rights.”

As various forms of technology that use biometric information like face IDs, retina scans or fingerprint matches have become more pervasive in both the private sector and the federal government, it’s raised concerns among privacy advocates about how this data is collected, who has access to it and what happens if it gets hacked.

TSA says the goal of the pilot is to improve the accuracy of the identity verification without slowing down the speed at which passengers pass through the checkpoints — a key issue for an agency that sees 2.4 million passengers daily. The agency said early results are positive and have shown no discernable difference in the algorithm’s ability to recognise passengers based on things like age, gender, race and ethnicity.