Combined method of multibeam sonar signal processing and image analysis for seafloor classification

The combined approach to seafloor characterisation was investigated. It relies on calculation of several descriptors (parameters) related to seabed type using three types of multibeam sonar data obtained during seafloor sensing: 1) the grey-level sonar images (echograms) of seabed, 2) the 3^D model of the seabed surface which consists of bathymetric data, 3) the set of time domain bottom echo envelopes received in the consecutive sonar beams. The proposed method has been tested using field data records acquired from several bottom types in the Gulf of Gdańsk and the promising results have been reported. This paper presents and discusses several processing techniques of the calculated descriptors in the context of their use in seafloor classification. In particular, the calculating the standard deviation of the descriptors for small subsets of data and the application of the Principal Component Analysis procedure (PCA) were investigated.