(color online) (a) Top side view of the 3-layer agar phantom. The electrical conductivities for the three layers were 0.2 S/m, 0.2 S/m, and 0.4 S/m respectively. Each layer was 10 mm in , and the distance from the transducer to the 1st interface of the agar phantom was 75 mm. (b) Compressed LFEIT pulse signals induced by the 1st, the 3rd and the 4th interfaces of the phantom.