3D VISUALIZATION OF SEABED FROM MULTIBEAM SONAR RECORDS USING TRIANGULAR IRREGULAR MESH. PACS REFERENCE: 43.58.Ta

Application of 3D imaging has been finding its place in many fields of marine science and technology and it has become almost indispensable tool in such areas like hydrography, marine navigation, seafloor mapping and characterization, marine GIS, ECDIS etc. Contemporary seabed mapping/imaging systems employing processed bottom echo records, acquired by a multibeam sonar, can map the bottom with the meter resolution. However, despite these advantages, even after employing data preprocessing, the method results in the excessive amount of data and the warehouse of petabytes. To address the problem of a compact representation of the huge amount of these raw data and an accurate seabed surface reconstruction from the multibeam sonar records, the paper proposes the data reduction algorithms developed for this purpose. The first one represents the smoothing procedure using B-spline surface obtained from a set of bathymetric 3D data retrieved from the sonar echoes. Whereas, the second one transforms the echo records to the discrete wavelet coefficients domain, and subsequently uses the wavelet shrinkage theory. The second stage in both methods consists of decimation procedure, which reduces the number of polygons in the mesh, while maintaining the sufficient resolution and accuracy of the reconstructed seabed surfaces. Both investigated methods seems to be quite promising tools for significant data reduction and compact representation of seabed 3D images retrieved from the sonar echoes