Robotics: Science and Systems VIII

FFT-based Terrain Segmentation for Underwater Mapping

Bertrand Douillard, Navid Nourani-Vatani, Matthew Johnson-Roberson, Stefan Williams, Chris Roman, Oscar Pizarro, Ian Vaughn, Gabrielle Inglis


A method for segmenting three-dimensional scans of underwater unstructured terrains is presented. Individual terrain scans are represented as an elevation map and analysed using fast Fourier transform (FFT). The segmentation of the ground surface is performed in the frequency domain. The lower frequency components represent the slower varying undulations of the underlying ground whose segmentation is similar to de-noising / low pass filtering. The cut-off frequency, below which ground frequency components are selected, is automatically determined using peak detection. The user can specify a maximum admissible size of objects (relative to the extent of the scan) to drive the automatic detection of the cut-off frequency. The points above the estimated ground surface are clustered via standard proximity clustering to form object segments. The approach is evaluated using ground truth hand labelled data. It is also evaluated for registration error when the segments are fed as features to an alignment algorithm. In both sets of experiments, the approach is compared to three other segmentation techniques. The results show that the approach is applicable to a range of different terrains and is able to generate features useful for navigation.



    AUTHOR    = {Bertrand Douillard AND Navid Nourani-Vatani AND Matthew Johnson-Roberson AND Stefan Williams AND Chris Roman AND Oscar Pizarro AND Ian  Vaughn AND Gabrielle Inglis}, 
    TITLE     = {FFT-based Terrain Segmentation for Underwater Mapping}, 
    BOOKTITLE = {Proceedings of Robotics: Science and Systems}, 
    YEAR      = {2012}, 
    ADDRESS   = {Sydney, Australia}, 
    MONTH     = {July},
    DOI       = {10.15607/RSS.2012.VIII.009}