A New Algorithm to Reconstruct EIT Images: Node-Back-Projection Algorithm

The approximately closed formula of voltage distribution on the boundary was resulted from those discrete data measured from electrodes by polynomial curve fitting method (PCFM). In addition, an assumption of equivalent potential distribution was proposed according to equivalent potential relation between the boundary voltage and inner node. Then, the correlation between the variation of inner node impedance and that of boundary voltage, node-back-projection algorithm (NBPA) was put forward accordingly. So the variation of inner node impedance was directly obtained from the variation of boundary voltage measured and electrical impedance tomography (EIT) was reconstructed by the interpolated algorithm, the resolution of image was improved. In this algorithm, the calculation of impedance for surface and volume was not needed, neither is iterative calculation. With the features of fewer calculations and quickly imaging, the new algorithm is suitable for the reconstruction of 3D EIT. In the meantime, a simple and feasible method was put to realize the real time inspection and measurement.