TexAn: textural analysis of sidescan sonar imagery and generic seafloor characterisation

Geophysical and environmental seafloor surveys make an extensive use of sidescan sonar imagery. Most of it is still interpreted visually and qualitatively. We are presenting here a method of textural analysis, with supplements the interpreter with reliable quantitative results. The TexAn technique has been extensively ground-truthed in complex mid-ocean ridge terrains, using submersible and ROV observations, and in-situ sampling. The frequencies used so far range from 6.5 kHz to 500 kHz; all applications have been validated and ground-checked. Current applications cover very different environments, from mid-ocean ridges to continental margins and coastal waters. TexAn enables quantitative assessments of sidescan sonar imagery, at all stages of processing and in all conditions. TexAn also reveals details hitherto invisible to the human eye, however experienced