The Bathymetry Assessment System: Efficient depth mapping in shallow seas using radar images

With the operation of the European Remote Sensing (ERS) satellites and RADARSAT, radar images are now readily available. One of the new applications of radar images is their use for bathymetric mapping in shallow seas. The Bathymetry Assessment System (BAS), described in detail in this paper, constructs accurate depth maps from radar images and a limited number of echo soundings. The BAS consists of a forward imaging model and an inversion part. The system needs a first guess depth map that may be derived from echo soundings or an old map of the area. The forward model calculates a simulated radar image. This is compared with the actual radar image by evaluating a penalty function. The penalty function also contains a term that compares model depths with measured depths and a term that contains a smoothness criterion, prohibiting speckle noise to be interpreted as depth variations. The inversion part of the system consists of optimization of the penalty function. This leads to an iterative procedure in wh...