On variance based methods in computer-aided phonocardiography

New trends in cardiosignal processing show that local fluctuations of the signals may reveal important information for computer-aided analysis. Even though the calculation of variance as a global measure is valuable, variation described locally and in one or more scales can represent a convenient way to describe details found in a signal. In this paper, several experimental results obtained using variance based methods, such as local variance estimation and multifractal detrended fluctuation analysis (MF-DFA), are discussed in interpreting phonocardiograms and their content. The experiments show promising results for computer-aided phonocardiography that can be implemented at low cost.