Based on analyzing the distributions of equipotential lines and capacitance sensitivity fields

this paper discusses the "soft fields" characteristics of electric field distributions for electrical capacitance tomography. The mechanism leading their inversions to nonlinear ill-posed problems is also studied.We employ a three-layer B-P neural network to reconstruct images. The input vector of the network is the preprocessed capacitance measurements and the output corresponds to the spatial image. Experimental results illustrate that this method is fast and accurate for image reconstruction.