Electrical impedance tomography measurement system for experimental use

In electrical impedance tomography (EIT) currents are applied into a volume through electrodes and the resulting voltages at the electrodes are measured. The impedance distribution inside the volume can then be calculated by solving the associated inverse problem. Usually the equipment that is needed for the generation of the current patterns and the measurements are large, expensive and tailored to specific situations. In such cases many of the measurement parameters are fixed and the user cannot change these to adapt the equipment to another measurement situation. In this article we present a simple and affordable EIT measurement device that is based on a PC computer, commercial data acquisition board and software and an external current generation and switching board. We also verify the performance and applicability of the system with a phantom measurement and an unusual measurement object for which there is no specific equipment, that is, the measurement of internal impedance distribution of spruce logs. (C) 1996 American Institute of Physics.