Cepstrum technique for multilayer structure characterization

The triple cepstrum, the third power of the inverse Fourier transform (IFT) of the logarithm of signal power spectrum, is used to characterize two-layer structures. The thickness of each layer can be found from the positions of the peaks in the triple cepstrum. Simulations and preliminary experiments have shown that the relative reflection coefficients can be reconstructed, in the ideal and lossless case, from the polarity and the amplitude of these peaks, as predicted by theory. The impedance pattern can be predicted even at low signal to noise ratio. A potential application of this method is to characterize blood vessel walls. The resulting thickness and impedance pattern could be useful in detecting and classifying plaques, particularly in the early stages.