Image of a passenger appears on the screen as Transportation Safety Administration employees demonstrate new body scanner software in Arlington, Virginia
The image of a passenger appears on the screen as Transportation Safety Administration employees demonstrate new body scanner software that uses a stick figure to represent the passenger being scanned, rather than an actual image of the person, at the TSA Systems Integration Facility at Washington's Reagan National Airport in Arlington, Virginia, February 1, 2011. REUTERS

U.S. aviation security authorities on Tuesday unveiled a new pilot program aimed at quelling an uproar about full-body scanners used to screen air travelers -- the new software will no longer produce an image of the actual person.

The Transportation Security Administration is deploying new software for scanners in three U.S. airports that will show screeners an alert on a generic male or female figure only if an anomaly is detected and highlight the spot of concern.

The agency has been under fire for using the full-body scanners -- designed to detect hidden explosives or other weapons -- because they showed a revealing picture of a person. Travelers and civil liberties advocates argued they were unconstitutional and an invasion of privacy.

We believe it addresses the privacy issues that have been raised since the AIT (advanced imaging technology) equipment has been deployed since the fall of '07, TSA Administrator John Pistole told reporters after a demonstration of the new software at a testing facility at Ronald Reagan Washington National Airport.

TSA has begun using the new software on a scanner at Las Vegas McCarran International Airport and will expand it to one each at Hartsfield-Jackson Atlanta International Airport and National Airport in the coming days.

We have high hopes for it, but obviously we want to make sure that we are getting it right in terms of not only lab testing ... but also operationally tested in these airports, Pistole said.

A few months ago Pistole said that similar software used on body scanners in Europe had too many problems with detecting real threats, but TSA officials said they have worked with the manufacturer and their technology experts to address those issues for the scanners in the United States.

If the tests are successful, TSA plans to use the software in all of the scanner machines in service. There are about 500 full-body machines at 78 U.S. airports.

The new software presently only works with the millimeter wave scanners made by L-3 Communications, about half of the machines in use, but they are working on similar software for the scanners that use backscatter technology.

TSA hopes to double the number of full-body scanners at U.S. airports this year, but that could be difficult because of the current fight between the Congress and the Obama administration over the federal budget.

The administration has raced to use more of the body scanners after the failed attempt on Christmas Day 2009 by a Nigerian man who is accused of trying to ignite a bomb hidden in his underwear aboard a flight from Amsterdam to Detroit.

If passengers decline to go through the body scanners, they have been required to undergo a physical patdown by a TSA officer which includes their groin and chest areas, provoking further backlash about invasion of privacy.

Despite the public uproar in November about the scanners, only about 132 people filed complaints with the TSA about the screening procedures that month, according to figures released by the Department of Transportation.

(Editing by Mohammad Zargham)