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  • Blind separation of independent acoustic emission sources
    Kosel, Tadej ; Grabec, Igor
    One non-destructive testing method is acoustic emission analysis, which is used for the characterisation and location of acoustic emission sources. Acoustic emission sources are often a mixture of ... various statistically independent source signals generated in a material. One of the most difficult problems of acoustic emission analysis is the separation and characterisation of the independent acoustic emission sources without knowing source signals and the mixing function. Both the source signals and the way the signals were mixed are unknown. Recently, Blind Source Separation (BSS) by Independent Component Analysis (ICA) has been the focus of attention to solve these problems. Independent Component Analysis is based on neural networks and uses minimisation of mutual information for the cost function. There are two variations of this method. The first deals with the instantaneous mixtures and the second with the convolutive mixtures of the independent sources. The main purpose of this work is to determine if independent component analysis is also useful for separation of independent acoustic emission sources and if it is possible to locate separate sources in laboratory specimens using an adaptive locator which is based on non-parametric regression. Some computer simulated and real experiments were performed on two test specimens and with several different acoustic emission sources. It was found that independent components analysis can be used to separate the independent acoustic emission sources with some limitations which are valid for this kind of method. A negative influence on blind source separation is also exerted by dispersion of acoustic waves, which is a property of the waveguides e.g. plates and ribbons. The majority of acoustic emission test specimens have such properties. It was also found that, with independent component analysis which uses convolutive mixtures, it is possible to locate independent acoustic emission sources.
    Source: Abstract book (Paper E1.05)
    Type of material - conference contribution ; adult, serious
    Publish date - 2001
    Language - english
    COBISS.SI-ID - 4476699

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