Patent ID: 7408461

Claim:
A method for detecting ferromagnetic objects within a sensing region of an array of magnetic field fluxgate sensors, the method comprising: receiving a signal to initiate a data acquisition and image acquisition cycle; generating a plurality of first output signals, each first output signal having a frequency that is substantially proportional to a magnetic field detected by a corresponding magnetic field fluxgate sensor; generating a plurality of second output signals, each second output signal having a frequency that substantially comprises an absolute difference between the frequency of a first output signal and the frequency of a corresponding background reference signal; converting the frequency of each second output signal to a corresponding voltage level; acquiring an image of a person within the sensing region of the array of magnetic field fluxgate sensors; and displaying the image of the person, overlaid with data representing the voltage levels corresponding to the frequencies of the plurality of second output signals, wherein the overlaid data indicates the magnitude and location of magnetic moments surrounding ferromagnetic objects within the sensing region.