Patent ID: 8280690
Filing Date: 2012-10-02
Classification: G01B

Abstract:
1. A signal processing method to determine at least one dimension of a nonferrous, electrically conducting object by measuring the reaction of a magnetic field to a change in excitation, where the magnetic field is being applied to the object, comprising the steps of: acquiring multiple samples of the time-dependent reaction of the magnetic field, obtaining from the multiple samples a measured field Laplace transform transfer function which represents actual dynamic behaviour between the excitation and the measured field reaction, and determining, via software executing on a signal processing unit, the at least one dimension of the object by fitting the measured field Laplace transform transfer function to a predetermined field Laplace transform transfer function, where the predetermined field Laplace transform transfer function represents the dynamic behaviour between the excitation and the measured field reaction with the at least one dimension as a parameter; and a part of the predetermined field Laplace transform transfer function represents the transmission behavior of the object for a magnetic field and another part of the predetermined field Laplace transform transfer function represents the reflection behavior of the object for a magnetic field.