Extraction of Line Spectrum of Ship Radiated Noise Based on Harmonic Wavelet

Traditional methods can hardly extract the line-spectrum components of ship-radiated noise accurately in low signal to noise ratio.This paper presented a high resolution method of line-spectrum extraction based on harmonic wavelet transform.By using harmonic wavelet transformation,the ship-radiated noise was decomposed into separate orthogonal frequency bands with no leakage,and the harmonic wavelet coefficients of the frequency bands which contain line spectra was extracted while other bands were set to zero.Then,the line spectra signals was reconstructed in time domain,so that the signals were separated from other components.Experimental results showed that the proposed method was effective in the background noise suppression,and its performance of the weak line-spectrum extraction was superior to Fourier analysis and was about 5 dB higher than FIR filter methods.