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The regular striations exhibited in broadband noise spectrogram due to a moving ship have been exploited for inverse problems in underwater acoustics, e.g., sediment geoacoustic characterization and source ranging. The enhancement of the underlying interference structure for striation extraction has been a hot topic for relative applications. In this paper, a straightforward method based on the low-frequency...
This paper presents our preliminary geoacoustic inversion results of the ship noise data collected by a vector sensor in 2008, Dalian, China. For the at-sea measurement, a fishing boat was served as a passive source passed by the receiver boat deploying a vector sensor, which collected the pressure field and particle velocity components at three orthogonal directions of X, Y and Z. A batch inversion...
An uniform distribution often appears in the space-frequency plane for broad-band, low-frequency sound intensity generated by a moving source in a shallow water environment. Waveguide invariant theory is used to interpret this phenomenon, and it has been applied for inverse problems in underwater acoustics. A vector sensor has advantages in providing both pressure and particle velocity information...
The Hilbert-Huang transform (HHT) has the advantage in dealing with non-stationary signals, for its data driving. However there are some limitations of the original HHT. For getting more benefits in frequency resolution, an improved HHT is applied in this paper. In the improved version, the instantaneous harmonic retrieval method is applied to calculate the instantaneous frequencies of the intrinsic...
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