Registration and variability of side scan sonar imagery

Abstract

This thesis presents the results of several experiments performed on side scan sonar equipment and imagery with the aim of characterizing the acoustic variability of side scan sonar imagery and applying this information to image rectification and registration. A static test tank experiment is presented which analyzes the waveform, power spectral density, and temporal variability of the transmitted waveform. The results of a second static experiment conducted from the Woods Hole Oceanographic Institution Pier in Woods Hole, Massachusetts permit determination of the distribution and moments of intensity fluctuations of echoes from objects imaged in side scan sonograms. This experiment also characterizes temporal and spatial coherence of intensity fluctuations. A third experiment is presented in which a side scan sonar towfish images the bottom adjacent to the pier while running along an underwater track which reduces towfish instability. Imagery from this experiment is used to develop a rectification and registration algorithm for side scan sonat images. Preliminary image processing is described and examples presented, followed by favorable results for automated image rectification and registration.