FIELD: physics.
SUBSTANCE: metal detector (100, 300) comprises at least first coil (102) for generating a first magnetic field (108) along first direction (119). First coil is a divided coil with first (104) and second (106) sections. Source (110) of coils supply separately supplies time-varying power supply to sections of coil. At least one electrical sensor (116, 118) for measuring electrical data (136) represents power supplied to at least a first coil portion and a second coil portion. Memory (130) contains machine executable instructions (140, 142, 340) and metal object search pattern (134), which contains power supply commands for control of power supply for supply of independently varying in time power supply to set of coils. Commands of the power supply source further cause the power supply to supply the time-independent power supply to the first coil portion and the second coil portion to create within the measurement zone an attenuated field area (109) having a time-varying magnetic field component with a value below a predetermined magnetic field intensity. Metal object search pattern further induces the coil power supply to vary the current supplied to the set of coils in order to move the weakened area in preset pattern (322) within the measurement zone. Execution of instructions causes the processor to control (200) the power supply using the metal object search pattern to move the weakened area in the preset pattern, to measure (202) by at least one electrical sensor electrical data during movement of the weakened region in the given pattern, determining (204) the location of at least one metal object within the measurement zone by detecting a change in electrical data when the weakened field area moves in a predetermined pattern.
EFFECT: invention relates to metal detectors used for magnetic resonance imaging.
15 cl, 9 dwg
