In certain situations it is useful to identify an unknown sample of metal without contact or visual inspection. We wish to do this by inducing a current in a coil and placing the sample in the resulting magnetic field. For the special case in which the sample is an infinite slab, we have a model that gives the change in impedance of the coil based on the properties of the sample. In this paper we analyze the inverse problem of finding the metal properties from impedance measurements over a wide range of frequencies.
Mathison, Chase and Booton, Laura, "Determining Properties of Metal by Analyzing Changes in Impedance" (2012). Mathematical Sciences Technical Reports (MSTR). 3.