Security system and method of detecting contraband items

Abstract

A method of detecting contraband about a person using a portable detector apparatus having an elongate housing that supports at least one magnetic sensor, which is arranged to produce a signal indicative of an ambient magnetic field or gradient over a zone of sensitivity which extends away from the housing, the size of the zone large enough to contain the whole body of the person, and a signal processing circuit that receives as an input the signal from the magnetic sensor and which, in response to a change in the signal, produces an alert signal includes setting up the portable detector apparatus in a chosen location, causing the person to pass alongside the housing from outside of the zone of sensitivity into the zone of sensitivity, and monitoring for the issue of an alert by the device which is indicative of the possible presence of contraband.

1 . A method of detecting contraband about a person using a portable detector apparatus comprising an elongate housing that supports at least one magnetic sensor which is arranged to produce a signal indicative of an ambient magnetic field or gradient over a zone of sensitivity which extends away from the housing, the size of 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; the method comprising:
 setting up the portable detector apparatus in a chosen location; and   causing the person to pass alongside the housing from outside of the zone of sensitivity into the zone of sensitivity, monitoring for the issue of an alert by the device which is indicative of the possible presence of contraband.   
     
     
         2 . A method according to  claim 1  which comprises, in the event of an alert being issued, performing additional security screening of the person to locate the possible contraband. 
     
     
         3 . A method according to  claim 2  in which the step of additional screening comprises at least one of: sweeping the person with a hand held metal detector, performing a pat down, and a cavity search. 
     
     
         4 . A method according to  claim 1  which comprises locating the apparatus in any one of: a constricted area such as in a corridor, and or just before or after a doorway. 
     
     
         5 . A method according to  claim 1  which comprises employing at least one screening strategy. 
     
     
         6 . A method according to  claim 5  in which the strategy comprises at least one of a surprise strategy, a semi-surprise strategy, and a covert strategy. 
     
     
         7 . A method according to  claim 6  in which the covert strategy comprises positioning the detector apparatus on a first side of a wall or other obstacle such that the zone of sensitivity covers a region on the second, opposing, side of the wall or obstacle, the second side comprising the chosen location for the screening, a person within the chosen location being unable to see the apparatus. 
     
     
         8 . A method according to  claim 7  in which the apparatus includes a remote alarm unit, which can be located away from the housing on the second side of the wall. 
     
     
         9 . A method according to  claim 1  which comprises providing an apparatus having a housing where the zone of sensitivity is defined by a region bounded at single edge by the housing and in which all other points within the zone of sensitivity are further away from the housing, the zones of sensitivity extending on two opposing sides of the housing, and causing at least one person to move into a zone on one side and another person to move into the zone on the other side. 
     
     
         10 . A method according to  claim 9  which comprises causing a plurality of people to form two lines, and to file past each side of the apparatus substantially in parallel. 
     
     
         11 . A method according to  claim 1  in which the detector apparatus includes a carry case into which the detector can be packed. 
     
     
         12 . A method according to  claim 11  in which the apparatus is operable between a packed state inside the carry case to a ready to use state outside of the case in less than 30 seconds. 
     
     
         13 . A method according to  claim 1  in which the apparatus includes a stand which enables it to be quickly and easily erected at any point where contraband detection is required. 
     
     
         14 . A method according to  claim 1  in which the detector apparatus is ruggedized so that it is capable of withstanding being pushed or pulled over in use without causing any damage to the operation of the device. 
     
     
         15 . A security screening installation system comprising:
 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.   
     
     
         16 . A security screening installation according to  claim 15  in which the wall comprises a material through which a magnetic field will pass relatively unimpeded. 
     
     
         17 . A security screening installation according to  claim 16  in which the wall or object is located within a controlled environment such as a prison. 
     
     
         18 . A security screening installation according to  claim 15  or  claim 16  which further includes a remote alarm unit, which can be located away from the housing on the second side of the wall. 
     
     
         19 . A method of making safe an object which may be concealing contraband comprising:
 setting up in a fixed location a portable detector apparatus comprising a single elongate pole housing 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;   causing the object to move from outside of the zone of sensitivity past the chosen location into the zone of sensitivity; and   monitoring for the issue of an alert by the device which is indicative of the possible presence of contraband.   
     
     
         20 . A method according to  claim 19  in which the object comprises a laundry bag which contains laundry. 
     
     
         21 . A method according to  claim 20  in which the object comprises bedding from an inmate's cell. 
     
     
         22 . A method according to  claim 20  in which the object comprises a food or beverage can, such as aluminium cans. 
     
     
         23 . A method of increasing safety in a controlled environment, such as a prison, comprising carrying out a series of screenings at locations within the controlled environment, the method comprising using a portable detection apparatus which includes at least one magnetic sensor that is sensitive to the ambient magnetic field to detect contraband, and subsequently performing additional searching of any person or object which is suspected to have contraband.