The method of electrical impedance tomography, which calculates images of the electrical conductivity inside the body based on surface measurements is considered. The basis of the method is an alternating electric current, which is supplied to various configurations of injecting and detecting electrodes located on the body surface and the potential field that arises in its volume is measured. It is shown that each link of the hardware that implements the electrical impedance tomography method has an impact on the final visualization. The implementation essence of the software part of the method based on the Laplace equation is stated. It is advisable to use the results of the work when monitoring the respiratory and cardiovascular systems using a chest belt with electrodes.