| 摘要 |
A method of detecting contraband about a person is disclosed, and a security screening installation system, for use in detecting contraband. The system comprises: a detector apparatus which includes at least one magnetic sensor arranged to produce a signal indicative of an ambient magnetic field or gradient over a zone of sensitivity around the sensor, the zone being large enough to contain the whole body of the person, and a signal processing circuit which receives as an input the signal from the magnetic sensor and which, in response to a change in the signal produces an alert signal; and a wall or other object behind which the detector apparatus is hidden, the detector apparatus being positioned so that at least part of the zone of sensitivity extends in front of the wall or other object and is large enough for a person to fit wholly within the zone. The method may alternatively comprise setting up a particle detector apparatus in a chosen location and moving people past the detector. |
