Underwater Mapping Using Gloria and MIPS

Advances in digital image processing of Geological Long Range Inclined ASDIC (GLORIA) sidescan sonar image data have made it technically and economically possible to map large areas of the ocean floor including the Exclusive Economic Zone. Software was written to correct both geometric and radiometric distortions that exist in the original "raw" GLORIA data. Preprocessing GLORIA-specific algorithms include correctlons for slant-range geometry, water column offset, aspect ratio distortion, ship\´s velocity changes, speckle noise, and shading due to signal dropoff as a function of range. A digital mosaicking technique was developed enabling 2- by 2-degree quadrangles to be generated. This operational software package is part of the U.S. Geological Survey\´s Mini Image Processing System.