Study on Metal Detection with Electromagnetic Induction Probe Utilizing Rotating Magnetic Field

The present paper describes an investigation conducted on metal detection with a scanning probe. The authors applied a rotating magnetic field probe to metal detection. The rotating magnetic field probe was composed of two vertically placed rectangular exciting coils and a circular detecting coil. The experimental results confirmed that the probe could detect metal objects and provide more information about their shape, direction, and electromagnetic characteristics than conventional metal detector probes. A two-dimensional signal display shows a blurred image of the metal object and the signal phase indicates the object's direction and electromagnetic characteristics. The experimental results showed that excellent restoration of the surface shapes of metal objects can be obtained for both magnetic and nonmagnetic metals under present conditions. There is also a possibility that the rough shape of a metal object can be estimated from the restored image. (C) 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(4): 1-11, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21178