The Transportation Security Administration (TSA) began testing a new, more modest body scanning system at three airports. They hope it will assuage critics' concerns that the nearly 500 full-body scanners at 78 airports reveal too much.

"We believe it addresses the privacy issues that have been raised," TSA chief John Pistole said at a news conference at Reagan National Airport in Washington, one of the airports testing the technology.

The system does not involve new machines. Instead, it relies on new software.

The software discards the x-ray-style image that revealed the contours of the traveler's body — the one that left many uncomfortable at the thought of screeners being able to see them with the rough outlines of their undergarments.

Now, there is just a generic image — like the chalk outline of a body at a crime scene.

"One of the things this does is give greater confidence to the traveling public, because they are seeing the image also. They are seeing exactly what the security officer is seeing, that they can say 'Oh, yeah, I forgot to take that piece of paper out of my pocket,'" Pistole said. "And hopefully it provides a greater deterrent to possible terrorists, who may realize 'Ok, they're going to see it right there. If that shows up, and I'm here, then I'm going to be caught,'" he added.

In addition to Reagan National airport, the new machines will be tested at McCarran International Airport in Las Vegas and Hartsfield-Jackson International Airport in Atlanta.

If all goes well for two months, TSA said it can install the software to 250 of the scanners nationwide at a cost of $2.7 million.