Patent ID: 6275030
Filing Date: 2001-08-14
Classification: G01N

Abstract:
A method for determining properties of an electrically conductive object to be measured, comprising the steps of:transmitting a time varying electromagnetic field from a transmit antenna to said object for generating eddy currents in said object;detecting an electromagnetic signal S(t) generated by said eddy currents using a receiving antenna; anddetermining properties of said object from said signal S(t) by selecting certain .tau..sub.i and ##EQU19##such that ##EQU20##i=1, 2, . . . n (4)and ##EQU21##wherein .alpha., .beta., .gamma., .delta., and m are real numbers dependent on geometry of said object, of said transmitting antenna and of said receiving antenna;wherein said real numbers are further dependent on relative positions of said object, said transmitting antenna and said receiving antenna;wherein .mu..sub.i represents magnetic permeability of an area i of said object and .sigma..sub.i represents electrical conductivity of an area i of said object; andwherein said areas i (i=1, 2, . . . n) together generate said electromagnetic S(t).