Sensitivity of metal detectors to spheroidal targets

Author

Silvester, Peter P. ; Omeragic, D.

Author_Institution

Dept. of Electr. Eng., McGill Univ., Montreal, Que., Canada

Volume

33

Issue

6

fYear

1995

fDate

11/1/1995 12:00:00 AM

Firstpage

1331

Lastpage

1335

Abstract

The sensitivity of magnetic metal detectors to prolate or oblate spheroidal targets depends both on the semiaxis ratio and on the orientation of the spheroid polar axis relative to the local magnetic field. A spherical target produces null response only if the generator and detector coil magnetic fields are orthogonal, but the spheroid possesses a null direction for a large range of magnetic field orientations. A spheroid can therefore be made undetectable by rotating it into a particular orientation. The existence of such blind-position angles is investigated theoretically in detail and families of curves are given to illustrate them in a particular case

Keywords

geophysical prospecting; geophysical techniques; terrestrial electricity; blind-position angle; buried object detection; curve; geoelectric; geology; geophysical measurement technique; magnetic metal detector; null response; orientation; sensitivity; spheroid polar axis; spheroidal target; terrestrial electricity; theory; Coils; Detectors; Food industry; Magnetic fields; Metals industry; Nails; Object detection; Shape; Signal processing; Voltage;

fLanguage

English

Journal_Title

Geoscience and Remote Sensing, IEEE Transactions on

Publisher

ieee

ISSN

0196-2892

Type

jour

DOI

10.1109/36.477191

Filename

477191