Acoustic emission transient detection based on linear model residuals

Acoustic emissions (AE), which are ultrasonic waves created by the formation/propagation of a crack in a material, provide a possible avenue for automatic fault monitoring in machinery. In metal components, these AE signals are very complex transients that exhibit rapid time-varying behaviour due to multiple modes and multipath propagation. We present a scheme for the detection of AE transients that requires minimal a priori assumptions on the signal model. The technique, that is amenable to both adaptive and block implementations, is based on the thresholding of the ratio of the residual energy in fitting the transient to a linear model, to the signal energy. The method works well in detecting transients even at low SNR.