Side-scan sonar mapping and computer-aided interpretation in the Santa Barbara Channel, California

The authors have experimented with digital processing of side scan sonar data taken in a 14 sp-km area of continental shelf offshore Southern California. The data were FM tape recorded during the survey and digitized and processed later in the laboratory. The digital image processing included both image correction and image enhancement. Geometric corrections were applied to correct for image distortions due to variable ship position and speed and sonar slant range. Enhancements that were tried included contrast stretching, band-pass filtering, image restoration (inverse filtering), and various edge enhancements such as density slicing and standard deviation filters. Interpretive procedures were also attempted and included digital mosaicing, stereoscopic viewing, and false-color display.