Latest trends in Security Scanners
A full-body scanner is a device that detects objects on or inside a person’s body for security screening purposes, without physically removing clothes or making physical contact. Depending on the technology used, the operator may see an alternate wavelength image of the person’s naked body, merely a cartoon-like representation of the person with an indicator showing where any suspicious items were detected or full X-ray image of the person. For privacy and security reasons, the display is generally not visible to other passengers, and in some cases is located in a separate room where the operator cannot see the face of the person being screened. Unlike metal detectors, full-body scanners can detect non-metal objects, which became an increasing concern after various airliner bombing attempts in the 2000s. Transmission X-ray body scanners can also detect swallowed items or hidden in body cavities of a person.
Security Scanners come in all shapes and sizes to meet the needs of a client ranging from hand-held scanners to mantrap cubicles, we take a few of some of these options that are becoming essential aspects of any buildings fittings.
Hand-Held metal detectors
Hand-held metal detectors are portable light weight devices and can be carried in the hand comfortably. They are mainly used at check points to detect metal targets in items that people may be carrying such as handbags or even pockets of various clothing. They are readily available and highly used in many of the buildings in commercial centers by security personnel as the first line of defense.
Walk through metal detectors
Walk through or portal detectors are common in public buildings, airports and military installations. Their portals are bracketed with two large coils or loop type antennae, one a source and the other a detector. Electromagnetic waves are emitted by the source coil into the detection space. When the electromagnetic field of the transmitted wave impinges on a conducting object, it induces transient currents on the surface of the object; these currents, in turn, radiate electromagnetic waves. These secondary waves are sensed by the detector coil.
Magnetic imaging portals
The magnetic imaging portal is a relatively new technology. Like walk-through metal detectors, it illuminates its detection space with radio-frequency electromagnetic waves. However, it does so using a number of small antennas arranged ring-like around its portal, pointing inward. Each of these antennas transmits in turn to the antennas on the far side of the array; each antenna acts as a receiver whenever it is not transmitting. A complete scan of the detection space can take place in the time it takes a person to walk through the portal. Using computational techniques adapted from computed axial tomography (CAT) scanning, a crude image of the person (or other object) inside the portal is calculated and displayed. The magnetic imaging portal may for some purposes be classed as a metal detector rather than as an imaging system because it does not produce a detailed image of the metal object detected, but only reveals its location and approximate size.
Man-trap cubicles
A man trap, or a security booth, is a security device that monitors and controls two interlocking doors. Many banks are fitted with these devices. Interlocking doors are doors that can never be open simultaneously. Either one of the doors can be unlocked and opened, as long as the other door is locked and closed. Between these interlocking doors is a small, secure space, which only admits one person at a time. These access control booths effectively separate a non-secured area from a secured area. Man traps are ideal in high value or critical security areas, like cash handling depots, sensitive data processing areas, critical research labs, security control rooms, jewelry stores and vaults.
Full Body Scanner
A full body scanner is used to reveal objects, including explosives and weapons that could be hidden under clothing. The technology, widely used in airports, is safe and effective and provides an alternative between full body scanning and a physical search in case selected for additional screening.
Back scatter
Back scatter radiation is the radiation that is reflected (scattered) from a material back towards the X-ray radiation source. X-ray security units using back scatter radiation operate by exposing the subject to low energy X-radiation. This low energy radiation passes through clothing but is readily scattered by dense objects. Some of the radiation is scattered back into a series of radiation detectors, and creates an image of the subject’s body, showing any items concealed under the clothing.
The person stands in front of the enclosure and is scanned by the X-ray beam, which has a typical cross-sectional area of approx. 25 mm2. Usually the person is scanned twice, once from the front and then from the back.
Transmission
Transmission radiation is the radiation that passes directly through the person being examined. This radiation can be measured by a detection system placed on the side of the person opposite to the X-ray source. Transmission X-ray security units use significantly higher X-ray energies than back scatter units to create a radio graphic image of the subject. The image is similar to those used for medical purposes and shows the skeletal structure of the subject, on which can be seen any contraband items, with sufficient X-ray absorption contrast, which the subject has swallowed as well as any weapons hidden on the body beneath the clothing. The person stands between the X-ray tube and the detector array and is scanned by an X-ray beam having a typical width of approx. 2 mm. The limiting quantity for the spatial resolution is the size of the detector elements.