Evaluation of Coil Location of TMR-based Electromagnetic Tomography Sensor

The application of TMR (Tunneling Magneto Resistance) sensor in Electromagnetic Tomography (EMT) system provides a novel idea for the improvement of system performance. In order to increase the number of independent measurement, the number of TMRs needs to be increased accordingly, and the coil location is an important parameter to be optimized. In this paper, an 8TMRs-8coils EMT sensor model and a 12TMRs-12coils EMT sensor model are built using finite element software. The image correlation coefficient is used as a quantitative evaluation index. The effect of the normalization method of measurement data, the step size of the Landweber iterative algorithm, and the coil location on the reconstructed image quality is investigated systematically. Based on the simulation results, the optimal step of the Landweber iteration algorithm and the normalization method are determined. The influence of the location of coils are qualitatively compared based on the reconstructed images and quantitatively evaluated according to the correlation coefficient between the reconstructed image and the ground truth. Based on the quantitative analysis, the optimal location of the coils are suggested.