Millimeter wave scanner
Encyclopedia
A millimeter wave scanner is a whole–body imaging device used for detecting objects concealed underneath a person’s clothing. Typical uses for this technology include detection of items for commercial loss prevention
Loss prevention
Retail loss prevention is a form of private investigation into larceny or theft. The focus of such investigations generally includes shoplifting, package pilferage, embezzlement, credit fraud, and check fraud...

, smuggling
Smuggling
Smuggling is the clandestine transportation of goods or persons, such as out of a building, into a prison, or across an international border, in violation of applicable laws or other regulations.There are various motivations to smuggle...

 and screening at government buildings and airport security
Airport security
Airport security refers to the techniques and methods used in protecting airports and aircraft from crime.Large numbers of people pass through airports. This presents potential targets for terrorism and other forms of crime due to the number of people located in a particular location...

 checkpoints.

It is one of the common technologies of full body scanner used for body imaging; a competing technology is backscatter X-ray
Backscatter X-ray
Backscatter X-ray is an advanced X-ray imaging technology. Traditional X-ray machines detect hard and soft materials by the variation in transmission through the target. In contrast, backscatter X-ray detects the radiation that reflects from the target...

. 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 read only the raw energy that is naturally emitted from the human body or objects concealed on the body. The key difference is that passive systems direct no energy at the subject being screened and are as safe as a digital camera
Digital camera
A digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...

 for both the screener and the subject.

Several countries employ the scanners for security screening. One of the most publicized millimeter-wave scanner systems is the Tadar system developed by Farran (now owned by Smiths Detection
Smiths Group
Smiths Group plc is a global engineering company headquartered in London, United Kingdom. It has operations in over 50 countries and employs around 23,550 staff....

). The name "Tadar" was inspired by the Brazilian Tadarida
Tadarida
The genus Tadarida has ten or more species of bats divided into two subgenera, with the first of these containing seven species spread across the Old World...

 bat.

Technical details

Clothing and many other materials are translucent in some EHF
Extremely high frequency
Extremely high frequency is the highest radio frequency band. EHF runs the range of frequencies from 30 to 300 gigahertz, above which electromagnetic radiation is considered to be low infrared light, also referred to as terahertz radiation...

 (millimeter wave) radio frequency
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...

 bands. This frequency range is just below the (related) sub-millimeter terahertz radiation
Terahertz radiation
In physics, terahertz radiation refers to electromagnetic waves propagating at frequencies in the terahertz range. It is synonymously termed submillimeter radiation, terahertz waves, terahertz light, T-rays, T-waves, T-light, T-lux, THz...

 (or "T-ray") range.

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.

Privacy concerns

Privacy advocates are concerned about the use of active millimeter wave technology because it effectively implements routine and, in many cases, mandatory virtual strip searches. It allows screeners to see the surface of the skin under clothing, prosthetics including breast prostheses, and other medical equipment normally hidden, such as colostomy bag
Ostomy pouching system
An ostomy pouching system is a medical device prosthetic that provides a means for the collection of waste from a surgically diverted biological system and the creation of a stoma...

s. Passive millimeter wave devices do not have the same privacy concerns because the images produced with passive screening technology expose no anatomical details.

While the radiation itself cannot distinguish between private and non-private areas, software imaging technology can 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 traditional "patdown". In locations such as the UK, the scans are mandatory.

In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, the Transportation Security Administration
Transportation Security Administration
The Transportation Security Administration is an agency of the U.S. Department of Homeland Security that exercises authority over the safety and security of the traveling public in the United States....

 (TSA) claimed to have taken steps to address privacy objections. TSA claimed that the images captured by the machines were not stored. Despite this the U.S. Marshals Service admitted that it had saved thousands of images captured from a Florida checkpoint. The officer sitting at the machine does not see the image; rather that screen shows only whether the viewing officer has confirmed that the passenger has cleared. Conversely, the officer who views the image does not see the person being scanned by the device. In some locations, updated software has removed the necessity of a separate officer in a remote location. These units now generate a generic image of a person, with specific areas of suspicion highlighted by boxes. If no suspicious items are detected by the machine, a green screen instead appears indicating the passenger is cleared.

Concerns remain about alternative ways to capture and disseminate the image. Additionally, the protective steps often do not entirely address the underlying privacy concerns. Subjects may object to anyone viewing them in a state of effective undress, even if it is not the agent next to the machine, or even if the image is not retrievable.

Claims that images are immediately destroyed were questioned after Indian film star Shahrukh Khan
Shahrukh Khan
Shahrukh Khan , often credited as Shah Rukh Khan, is an Indian film actor, as well as a film producer and television host. Often referred to as "the King of Bollywood", Khan has acted in over 70 Hindi films....

 joked that his image was circulated by airport staff at Heathrow in London. This comment appears to be a joke, but reports of full-body scanner images being improperly and perhaps illegally saved and disseminated continue to emerge.

Possible health effects

Millimeter wave radiation is not genotoxic
Genotoxic
In genetics, genotoxicity describes a deleterious action on a cell's genetic material affecting its integrity. This includes both certain chemical compounds and certain types of radiation....

 and cannot initiate cancer, unlike ionizing radiation
Ionizing radiation
Ionizing radiation is radiation composed of particles that individually have sufficient energy to remove an electron from an atom or molecule. This ionization produces free radicals, which are atoms or molecules containing unpaired electrons...

 such as high frequency ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 and x-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

s. While the majority of animal cancer studies show no response to chronic exposure of microwave
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...

 radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...

, some show an increased rate of tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

 growth. The same increase also occurs in chronically–stressed animals not exposed to radiation.

Effectiveness

The efficacy of millimeter wave scanners in detecting threatening objects has been questioned. Formal studies demonstrated the relative inability of these scanners in detecting objects—dangerous or not—on the person being scanned. Additionally, some studies suggested that the cost–benefit ratios of these scanners is poor. As of January 2011, there had been no report of a terrorist capture as a result of a body scanner. In a series of repeated tests, the body scanners were unable to detect a handgun hidden in an undercover agent's undergarments.

Deployment

While airport security may be the most visible and public use of body scanners, companies have opted to deploy passive employee screening to help reduce inventory shrink
Shrinkage (accounting)
In financial accounting the term inventory shrinkage is the loss of products between point of manufacture or purchase from supplier and point of sale. The term shrink relates to the difference in the amount of margin or profit a retailer can obtain...

 from key distribution centers.

The UK Border Agency
UK Border Agency
The UK Border Agency is the border control body of the United Kingdom government and part of the Home Office. It was formed on 1 April 2008 by a merger of the Border and Immigration Agency , UKvisas and the Detection functions of HM Revenue and Customs...

 (UKBA) uses passive sceening technology to detect illicit goods.

As of April 2009, the U.S. Transportation Security Administration
Transportation Security Administration
The Transportation Security Administration is an agency of the U.S. Department of Homeland Security that exercises authority over the safety and security of the traveling public in the United States....

 began deploying scanners at airports, e.g., at the Los Angeles International Airport (LAX). These machines have also been deployed in the Jersey City PATH train system
Port Authority Trans-Hudson
PATH, derived from Port Authority Trans-Hudson, is a rapid transit railroad linking Manhattan, New York City with Newark, Harrison, Hoboken and Jersey City in metropolitan northern New Jersey...

. They have also been deployed at San Francisco International airport (SFO), as well as Salt Lake International Airport (SLC
SLC
SLC may refer to, among other things:* Salt Lake City, Utah* Salt Lake City International Airport, IATA Airport Code* Salt Lake County, Utah* Sounds Like Chicken, a music group* South Lanarkshire Council* Southwestern Lacrosse Conference...

) and Indianapolis International Airport (IND
IND
IND may be:* the IOC country code, and ISO 3166-1 alpha-3 code for , used by the Republic of India* An abbreviation for the Institute of Notre Dame, a high school in Baltimore, Maryland* An abbreviation for Independent...

).

Three security scan
Security scan
A full-body scanner is a device that creates an image of a person's nude body through their clothing to look for hidden objects without physically removing their clothes or making physical contact...

ners using millimeter waves were put into use at Schiphol Airport in Amsterdam on 15 May 2007, with more expected to be installed later. The passenger's head is masked from the view of the security personnel.

One is currently in use in London Luton airport.

Passive scanners are also currently in use at Fiumicino Airport, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

. They will next be deployed in Malpensa Airport
Malpensa Airport
Milano Malpensa Airport "City of Milan" , former "Aeroporto Città di Milano" is Milan's largest airport. It is located 39.97 km northwest of central Milan, Italy...

.

The federal courthouse in Orlando, Florida employs passive screening devices capable of recording and storing images.

Canada

Kelowna International Airport
Kelowna International Airport
Kelowna International Airport is a Canadian airport located approximately 10 minutes or northeast of Kelowna, British Columbia, Canada, on Highway 97....

 in Kelowna
Kelowna
Kelowna is a city on Okanagan Lake in the Okanagan Valley, in the southern interior of British Columbia, Canada. Its name derives from a Okanagan language term for "grizzly bear"...

, British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

 hosted the first such device in a Canadian airport. It was pulled from service in 2008 for undisclosed reasons, but may have simply been a test unit on loan.

Scanners are currently in use at Pearson Airport in Toronto, Ontario (YYZ), Montréal - Pierre Elliott Trudeau International Airport, Quebec (YUL
Yul
YUL or Yul may refer to:*Yul Brynner, Russian-American actor*Yul Kwon, winner of Survivor: Cook Islands*Montréal-Pierre Elliott Trudeau International Airport, an IATA airport code*IATA railway code for Montreal-Dorval passenger rail station...

), Calgary International Airport, Alberta (YYC), Vancouver International Airport, British Columbia (YVR), and Halifax Stanfield International Airport, Nova Scotia (YHZ).

The Canadian Air Transport Security Authority
Canadian Air Transport Security Authority
The Canadian Air Transport Security Authority is a Canadian Crown corporation responsible for the security screening at the 89 designated airports in Canada...

 held a trial of the scanners at Kelowna International Airport in 2008. Before the trial, the Office of the Privacy Commissioner of Canada (OPCC) reviewed a preliminary Privacy Impact Assessment and CATSA accepted recommendations from the OPCC. In October 2009, an Assistant Privacy Commissioner, Chantal Bernier, announced that the OPCC had tested the scanning procedure, and the privacy safeguards that CATSA had agreed to would “meet the test for the proper reconciliation of public safety and privacy”. In January 2010, Transport Canada confirmed that 44 scanners had been ordered, to be used in secondary screening at eight Canadian airports. The announcement resulted in controversies over privacy, effectiveness and whether the exemption for those under 18 would be too large a loophole.

Other applications

Scanners can be used for 3D physical measurement of body shape for applications such as apparel design, prosthetic devices design, ergonomics, entertainment and gaming.

See also

  • Backscatter X-ray
    Backscatter X-ray
    Backscatter X-ray is an advanced X-ray imaging technology. Traditional X-ray machines detect hard and soft materials by the variation in transmission through the target. In contrast, backscatter X-ray detects the radiation that reflects from the target...

     (in security scanning applications)
  • Explosives trace-detection portal machine (puffer machine)
  • Full body scanner
  • Security theater
    Security theater
    Security theater is a term that describes security countermeasures intended to provide the feeling of improved security while doing little or nothing to actually improve security. The term was coined by computer security specialist and writer Bruce Schneier for his book Beyond Fear, but has gained...

  • Electromagnetic radiation
    Electromagnetic radiation
    Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...

  • Extremely high frequency
    Extremely high frequency
    Extremely high frequency is the highest radio frequency band. EHF runs the range of frequencies from 30 to 300 gigahertz, above which electromagnetic radiation is considered to be low infrared light, also referred to as terahertz radiation...

  • Microwave
    Microwave
    Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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