Development of electromagnetic tomography system using LCR meter.

Electromagnetic tomography technique has been developed for monitoring the electric conductivity and/or magnetic permeability distributions in industrial applications. It offers some advantages over other tomographic modalities, including low cost, no radiation and non-invasive. Most of the electromagnetic tomography measurement systems are implemented with specifically developed circuits. Generally, it is difficult to achieve high SNR while maintaining a high dynamic measurement range. In this paper, an electromagnetic tomography system based on commercial LCR meter (or impedance analyzer) is presented. The system can achieve multi-channel mutual inductance measurements by incorporating LCR meter with a custom-built programmable analog switch array. The four terminals of the LCR meter, i.e. Hp, Lp, Hc and Lc, can be connected to any transmitter and receiver coils via the switch arrays which is controlled by an Arduino MCU. The system can send the measured data to host PC via USB, thus acquiring the mutual inductance between any pairs of the coils. In this way, the complexity and scale of electromagnetic tomography system are significantly reduced. Preliminary results show the system has the advantages of high measurement accuracy and good data repeatability. The system SNR can achieve 60 dB.