Magnetic induction tomography: Comparison of the image quality using different types of receivers

Magnetic induction tomography is used to image the electrical properties inside a region of interest. The systems differ in the construction of the receiver channels which can be composed of coils or gradiometers. We will compare and discuss the image quality subject to two different types of receivers, different arrangements for the exciters and receivers and different signal-to-noise ratios. In order to evaluate the image quality, the point-spread function (PSF) was determined which is used for the calculation of the resolution and the correctness of the location of a perturbation. The results show that the PSF depends on (a) the location inside the object, (b) the type of receivers and (c) the configuration used, especially the location of the receiving and excitation channels. According to this, the local resolution is changed and has the maximum near the border of the object and decreases towards the centre of the object. In addition, the evaluation of the PSF shows a dislocation with respect to the underlying point-source position.