Building qualitative elevation maps from side scan sonar data for autonomous underwater navigation

Deriving a terrain model from sensor data is an important task for the autonomous navigation of a mobile robot. An approach is presented for autonomous underwater vehicles using a side scan sonar system. Some general aspects of the type of data and filtering techniques to improve it are discussed. An estimated bottom contour is derived using a geometric reflection model and information about shadows and highlights. Several techniques of surface reconstruction and their limitations are presented. A method is presented for feature extraction which is important for future data matching/fusion procedures