Postprocessing and Corrections of Bathymetry Derived from Sidscan Sonar Systems: Application with SeaMARC II
Abstract
A procedure for postprocessing bathymetry data provided by a phase-measuring sidescan sonarsystem is presented. The data were collected with the SeaMARC II system, and are generally characterized by a high level of noise and uneven spatial sampling. Before any spatial filtering is applied, data are selected to remove most of the obvious artifacts and to retain instantaneous depth profiles whose slant ranges increase monotonically from a central location to the edges of the swath. An extrapolation scheme, patterned after a potential field, is proposed to fill gaps in the coverage or to extend the bathymetric swath to that of the corresponding sidescan image when regridding the data to a rectangular frame. To fill the near nadir gap typically found in these data, a specific interpolation methodology is developed that takes into account the slant range of the first bottom return as received by the sidescan sonar itself or by a shipboard echo-sounder. Spatial low-pass filtering is applied through convolutions with parabolic windows whose width is proportional to the footprint of the acoustic beam along track and roughly 1/8 of the swath width across track. Mismatches of contour lines between adjacent tracks are reduced through a statistical method design to correct systematic profile errors.
Department
Center for Coastal and Ocean Mapping
Publication Date
10-1994
Volume
19, Issue 4
Journal Title
IEEE Journal of Oceanic Engineering
Pages
619-629
Publisher Place
Washington DC, USA
Publisher
IEEE
Digital Object Identifier (DOI)
10.1109/48.338398
Document Type
Journal Article
Recommended Citation
P. Cervenka and C. de Moustier, "Postprocessing and corrections of bathymetry derived from sidescan sonar systems: Application with SeaMARC II," IEEE Journal of Oceanic Engineering, vol. 19, no. 4, pp. 619–629, 1994.