I. Introduction
Electrical impedance tomography (EIT) mounts electrodes at the periphery of the imaging domain. Through an electronic data acquisition system, the low-frequency currents are applied at some of the electrodes, and the resulting voltage responses are measured at the rest of the electrodes. Then, the conductivity distribution inside the observation domain is recovered from the voltage measurements through some kind of reconstruction algorithm. Due to the advantages of noninvasion, nonradiation, low cost, and high portability, EIT has attracted much attention in the last two decades and owns many biomedical applications, e.g., brain function monitoring [1], microfluidic detection [2], and long-term and real-time bedside monitoring of human lungs [3], [4].