Seabed Characterisation Using Spectral Moments of the Echo Signal

The paper presents the analysis of suitability of use the spectral moments of the single beam echo envelope for seafloor characterisation and classification. For approximately 15000 averaged echo pulses acquired in the southern Baltic Sea area, the calculations of spectral moments were performed and the correlation of the results with bottom characteristic features in different sites was evaluated. The obtained results revealed that some spectral moments carry very useful information for the seafloor characterisation. Namely, it was shown that the spectral width, which measures the spectral power density concentration around the dominant frequency, might well describe the structure of sediment layers. In addition, the suitability of fractal dimension calculated using continuous wavelet coefficients is also presented. The chosen set of spectral echo parameters was used in a classification procedure based on the applied cluster analysis, giving the percentage of correct results near 90%.