  In this paper, an stereo-based traversability analysis approach for all
terrains in off-road mobile robotics, e.g. Unmanned Ground Vehicles (UGVs) is
proposed. This approach reformulates the problem of terrain traversability
analysis into two main problems: (1) 3D terrain reconstruction and (2) terrain
all surfaces detection and analysis. The proposed approach is using stereo
camera for perception and 3D reconstruction of the terrain. In order to detect
all the existing surfaces in the 3D reconstructed terrain as superpixel
surfaces (i.e. segments), an image segmentation technique is applied using
geometry-based features (pixel-based surface normals). Having detected all the
surfaces, Superpixel Surface Traversability Analysis approach (SSTA) is applied
on all of the detected surfaces (superpixel segments) in order to classify them
based on their traversability index. The proposed SSTA approach is based on:
(1) Superpixel surface normal and plane estimation, (2) Traversability analysis
using superpixel surface planes. Having analyzed all the superpixel surfaces
based on their traversability, these surfaces are finally classified into five
main categories as following: traversable, semi-traversable, non-traversable,
unknown and undecided.
