Correlation analysis of time-varying signals using wavelets

In this study, we proposed a new method to extract the components of target signals from the sound produced by a motorcycle and from the noise in the interior of a ship using an instantaneous correlation function based on wavelets. We also introduced the concept of using filters to limit the bandwidth of the observed signal to improve the accuracy of our method. We were thus able to observe the running conditions of the motorcycle and ship engine based on sounds that were produced within a noisy environment. This method may be useful in the sound design of engines, separation of sound sources and active noise control.