I always wondering how the body scanner works in the airport. How they can scan our body in the split second.
Thus this is the explanation after I google it.
Backscatter X-ray scanners and millimeter wave
scanners are full body scanners used in the screening area of airports
across the world. They functioning by sending low-level waves or rays towards your body and will be detecting the waves which scatter or bounce off the surface of your body as well as any object next to it. The machine will create the image and reveal any objects carrying under clothes such as liquid explosive, weapons and drugs.
Millimeter wave
scanners use
low-level radio frequencies (RF) to image subjects. This insures that
absolutely no radiation dose is given to the person being
screened: the energy that is directed towards the subject is not sufficient to
damage cells, DNA, or other atoms in the body.Millimeter wave scanners produce a 3D image of
the subject, contrary to Backscatter X-rays, which only produce a 2D image.
Backscatter X-ray machines use x-rays to give security personnel an
image of the exterior of a passenger’s entire body. These scanners are similar to medical x-ray machines except that they operate
at a much lower energy. This means that the radiation dose a person would
receive from a backscatter x-ray scan would be much lower than
the dose received from a medical x-ray. Another difference is that in medicine,
the radiation that passes through your body is used to create the picture.
Backscatter technology uses the x-rays that scatter (or “bounce”) off the
surface of your body, as well as any objects next to it, to create the image.
On the machines, the person’s body reads as white and all external items read as black. Here’s what it looks like when the scanner detects someone attempting to smuggle a handgun tucked into the front of his pants
References
Radiation Safety Institute of Canada
http://www.radiationsafety.ca/info-on-full-body-scanners
The daily dot: New study proves just how worthless TSA airport body scanners really are
http://www.dailydot.com/politics/tsa-rapiscan-body-scanner-study/
