Data acquisition system for impedance tomography for measuring the distribution of moisture in walls

The suggested project presents a new method for assessing the degree of moisture in buildings, basing on the distribution of conductivity inside the examined object. The image is obtained by processing numerically the measurements of potentials at the surface of the object by an impedance tomography method. In the paper a multi-port measuring data acquisition system for impedance tomography has been presented. The functional structure of the measuring system of the impedance tomography for measuring the distribution of moisture in walls is shown. The measuring system is equipped with current and voltage electrodes of a special design adapted for different construction materials, with an automatic switch-over of measuring channels and with an analog-to-digital converter. Uncertainty estimation of conductivity spatial distribution measurement requires the function of probability density to be determined for the conductivity value in the space considered. The research has been carried out as a part of the Ministry of National Education research project no. 4T07E 045 29.