Methods and Systems for Detecting, Localizing, Imaging and Estimating Ferromagnetic and/or Electrically Conducting Objects

A method for detecting a ferromagnetic or electrically conducting target object, comprising:

• providing one or more magnetic field transmitting devices and one or more magnetic field receiving devices;
• using each of said transmit devices to generate a magnetic field applied to a target according to:
• {right arrow over (B)}({right arrow over (r)})=[Bx({right arrow over (r)}),By({right arrow over (r)}),Bz({right arrow over (r)})]T,
• where {right arrow over (r)} is the position of the target in three dimensions, and x, y and z are three orthogonal directions in space;
• using each of said receiving devices to record the magnetic field that is generated by the target response;
• arranging the set of said recorded magnetic field measurements as a vector Bmeas that lies within a vector space of dimension N;
• selecting a hypothetical dipole source position;
• calculating a set of six orthonormal basis vectors uk that span the subspace of possible calculated data vectors for the selected dipole source position;
• calculating an estimate of the target response vector M as Mn=Σkvnk(uk·Bmeas) where k runs from 1 through 6 and vk=[v1k, . . . , v6k]T are a set of 6 orthogonal or orthonormal basis vectors that span the 6-dimensional subspace of possible solutions to the target response vector M.