Millimeter wave scanner

A millimeter wave scanner is a whole-body imaging device used for detecting objects concealed underneath a person’s clothing using a form of electromagnetic radiation. Typical uses for this technology include detection of items for commercial loss prevention, smuggling and screening at government buildings and airport security checkpoints. Several countries employ the scanners for security screening.

It is one of the common technologies of full body scanner used for body imaging; a competing technology is backscatter X-ray. Millimeter wave scanners themselves come in two varieties: active and passive. Active scanners direct millimeter wave energy at the subject and then interpret the reflected energy. Passive systems create images using only ambient radiation and radiation emitted from the human body or objects.

With active scanners, the millimeter wave is transmitted from two antennas simultaneously as they rotate around the body. The wave energy reflected back from the body or other objects on the body is used to construct a three-dimensional image, which is displayed on a remote monitor for analysis.

Historically, privacy advocates were concerned about the use of full body scanning technology because it used to display a detailed image of the surface of the skin under clothing, prosthetics including breast prostheses, and other medical equipment normally hidden, such as colostomy bags. These privacy advocates called the images "virtual strip searches". However, in 2013 the U.S. Congress prohibited the display of detailed images and required the display of metal and other objects on a generic body outline instead of the person's actual skin. Such generic body outlines can be made by Automatic Target Recognition (ATR) software. As of June 1, 2013, all full body scanners in use at U.S. airports have used ATR.

Software imaging technology can also mask specific body parts. Proposed remedies for privacy concerns include scanning only people who are independently detected to be carrying contraband, or developing technology to mask genitals and other private parts. In some locations, travelers have the choice between the body scan or a "". In Australia, the scans are mandatory however in the UK passengers may opt out of being scanned. In this case the individual must either be screened by an alternative method which includes at least an enhanced hand search in private, as set out on the UK Government website.

...
Wikipedia