Seconds after a passenger stepped through an advanced-imaging machine at a BWI Marshall Airport security checkpoint, an image of a human body popped up on a video screen.

It did not show the passenger's body as it appears under his clothing. No physical imperfections or private parts were in sight. And that is the point of the new technology demonstrated Friday at Baltimore-Washington International Thurgood Marshall Airport.

The image, displayed where both the passenger and a security officer could see it, bore little resemblance to the graphic depictions of individuals that have aroused the anger of many fliers. The screen simply showed a cartoonlike depiction of the human form, with a little yellow box superimposed over one of the passenger's legs — an area that needed to be checked further.

BWI is one of about a dozen U.S. airports where the Transportation Security Administration has deployed the new security software, and the agency hopes it will put to rest widespread complaints about a screening regimen that critics have labeled a "virtual strip search."

Among other things, the new software will eliminate the need for a TSA officer to be stationed in a screening room off the checkpoint — much like the Wizard of Oz behind his curtain — scrutinizing images of each person who passes through the machines.

The software was put into operation this week in 10 advanced-imaging machines already installed at BWI, and the rollout is part of an effort by the TSA to eliminate the creepiness factor from the enhanced screening program it adopted to detect explosives. The federal agency is spending $2.7 million to install the new program in 240 machines at 40 airports by this fall.

The "passenger" during Friday's airport demonstration was a TSA employee, and the yellow box told the security officer that the machine had detected something to be checked.

In this case, it turned out to be a penny in the man's pocket.

TSA spokesman Kawika Riley said the new software is just as effective as the version that provided a more graphic image of how people look under their clothes. "It meets the same security standards as it did before," Riley said.

TSA and airport officials invited the news media to the demonstration at the international terminal, letting reporters see how the software reacts when something suspicious is detected on a passenger.

TSA employees went through the imaging machine and held up their hands just as passengers have been doing since the devices were installed at the airport a few years ago.

After being scanned, they stepped through the device and were asked to wait a few seconds while images were processed. If nothing was found, all that showed up on the screen mounted on the outside of the device were the letters "OK" on a green field.

If the device detects what the TSA calls an "anomaly," the image that comes up is worthy of a "G" rating. Unlike the old system, in which the screener in the adjoining room could determine whether the scanned person was fat or thin, tall or short, and endowed with male or female organs, the new software erases all individuality.

"We've gotten rid of that viewing altogether. The software essentially does all the work for us," Riley said.

As the "passengers" moved through the checkpoint, TSA officers who took part in the demonstration confined their pat-downs to areas of the body where concerns were raised. When a woman came through and a yellow box showed up on the image on the screen, the officer performed a pat-down of the area and determined that the anomaly was merely a bra clasp.

"Thank you, sweetheart. Have a nice day," the female officer said.

Riley said the TSA believes the software change will allow passengers to move through security more quickly. One reason, he said, is that the officer at the checkpoint can see precisely where a problem has been detected. With the old software, he said, the officer had to receive verbal instructions from the viewing machine operator about which areas of the passenger's body to check.

In the long run, Riley said, the change probably will save the government money.

"With this technology there's no longer any need to have an officer assigned to a remote viewing room," Riley said. He added that the TSA would save on the costs of building and maintaining such rooms.

BWI Executive Director Paul Wiedefeld said the airport could put any square footage freed up by the elimination of the remote viewing rooms to good use.