Correlation Analysis of Time-Varying Signal Using Wavelets and Its Application to the Ship Interior Noise Analyses
Shunsuke Ishimitsu, Hajime Kitagawa, Satoshi Horihata, Noriyuki HAGINO · TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C · 2003
Generally, a wavelet transform with the analyzing wavelet described by a function, has been applied to time-frequency analyses of experimental data. In this study, measured signal is adopted to analyzing wavelet instead. Applying the proposed system, the correlation between acoustic and vibration signals from a wall and a floor in a mess hall, which is adjacent to an engine room of the training ship, is analyzed. As the traditional calculation of correlation repeats averaging procedure, the original signal must be stationary. To apply the method to time-varying signals, a new concept of instantaneous correlation factor, ICF, is introduced. As a conclusion, it is proved that a dominant feature of the correlation can be estimated by the ICF. The time-varying correlation could be analyzed and the starting point of main engine deceleration can be detected accurately.