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THE MACHINE THAT 'CAUGHT' BABA SUWE

By NBF News
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Operatives of the National Drug Law Enforcement Agency (NDLEA) seem to be at the crossroads after the arrest and detention of popular actor and comedian, Babatunde Omidina alias Baba Suwe over allegation of ingesting hard drug in his system.

The comedian has been subjected to observation by the agency since last week after its scanning machine at the Murtala Muhammed International Airport, Ikeja, allegedly detected 'foreign bodies' inside his body.

Though the story has since changed, as the suspect has not defecated anything close to cocaine since his arrest; but his case has, however, raised a lot of questions about the working of the super machine.

Sky Harbor International Airport was the first in the US that undertook the task of testing a new body-scanning machine to replace the metal detectors passengers walk through at the airports. This new body-scanning machine utilizes radio waves to detect foreign objects, creating an image based on energy reflected from the body. This digitally composed image is then viewed by an operator in a private screening room, where the faces of those being screen are blurred so that their privacy would be preserved.

The 3D images resemble that of a photo negative, where the passenger's body is coloured in silver tones against a black background. A media demonstration showed that a female model displayed nothing but the outline of her clothes, including the brassiere and underwear, but nothing else beyond the body's contours. The operation takes no more than five seconds to scan a whole body, which makes the boarding process much faster.

The devices use a mechanical collimator that moves a pencil-thin beam of x-ray over a person. Elements with low atomic numbers, such as carbon, oxygen, and other materials in the human body, scatter x-rays more, while higher number elements scatter less x-rays. The scattered photons are picked up by a detector next to the x-ray source that contains a scintillating material, which converts the x-rays to visible light. Photomultiplier tubes measure the intensity of the light, showing how strong any given spot on the subject scattered the x-rays. The system notes sharp changes in the scattering and uses that to draw outlines of objects the person is carrying.

The scanner operator sees an outline of the passenger's body, with other outlines around any object on that person, and can react accordingly. The operator gets no more information than the shape of the object. 'You might see a rectangle, for example, and you don't know if it's a wallet or a cellphone or a packet of C-4 (explosives),' Reiss, one of the manufacturers experts, said.

A scan exposes a passenger to a tiny amount of ionizing radiation.

How do the machines work?
There are two kinds of scanning devices - back-scatter and millimeter wave. Back-scatter scanning machines send narrow, low-density x-ray beams over the subject, front and back, at high speed, which just barely penetrates the clothing. The x-ray radiation reflects off the body – and off any objects hidden on that person. The process takes between six and eight seconds.

Millimeter-wave (mmw) machines are typically composed of twin vertical arrays of extremely high-frequency transmitters that circle the passenger and create a three-dimensional image. The transmitters emit beams of radio frequency (RF) energy, which bounces off sub-clothing surfaces and expose hidden items. Like back-scatter machines, the mmw scan requires several seconds before an image is produced.

Where are the machines, and who makes them?
These technologies are now in use at 65 U.S. airports, including all the major ones such as JFK in New York and Chicago's O'Hare, with more on the way. As at October, 189 back-scatter units and 152 mmw scanners are operational, and the Transport Security Administration (TSA), based in U.S., are looking to push the total number of machines to more than 1,000, with the goal to scan two out of every three air travellers before the end of 2011.

What can the machines actually see?
According to TSA, the scanners are only what airports require to keep weapons and explosives off airplanes. Each back-scatter device and the mmw machine produce different kinds of images. While the former creates an almost cartoonish two-dimensional snapshot of the inspection subject, the latter produces a holographic – 3D image.

Conscious of the need for privacy, the TSA has given assurances that every machine used at airports would feature face-and-genitalia-obscuring checks, what is called 'modesty algorithm.' TSA officials also stressed that the body scanners are incapable of data storage and that once an inspection ends and the image cleared, it disappears forever.

And as the controversy over Baba Suwe's case continues, some computer experts have said the possibility of the machine's failure cannot be ruled out since it is being operated by human. Beyond that they argued that because it requires greater expertise to handle the machine, those behind it should also undergo skill development training as regularly as possible.

According to Managing Director/Chief Executive Officer of Datapoint Microsystem, Lucky Uduikhue, the machine can fail, especially when the sensor or signal detector is not working effectively. In this case, he said, it might see a particle and read it as positive or even unable to detect at all in rare cases. He therefore, advised that there should be sufficient training for handlers.

'Human error can also contribute to machine failing to perform accurately, because most of these scanning machines are very effective if the people operating them are well-trained. Most mach