Electromagnetic Induction Spectroscopy

摘要

An object, made partly or wholly of metals, has a distinct combination of electrical conductivity, magnetic permeability, and geometrical shape and size. When the object is exposed to a low-frequency electromagnetic field, it produces a secondary magnetic field. By measuring the broadband spectrum of the secondary field, we obtain a distinct spectral signature that may uniquely identify the object. Based on the response spectrum, we attempt to “fingerprint” the object. This is the basic concept of Electromagnetic Induction Spectroscopy (EMIS). EMIS technology can be particularly useful for detecting buried landmines and unexploded ordnance. By fully characterizing and identifying an object without excavation, we should be able to reduce significantly the number of false targets. EMIS is applicable to many other problems where target identification and recognition (without intrusive search) are important. For instance, an advanced EMIS device at an airport security gate may be able to identify a particular weapon according to its maker and type. Other potential applications may include industrial sorting processes and robotics.