Scale space and free space topology analysis for omnidirectional images

This work is part of a global framework that aims to build a complete set of algorithms for autonomous robot exploration, navigation and map building using a sole omnidirectional camera. It focuses on topology extraction of navigable free spaces to yield autonomous robot exploration. The paper proposes a new algorithm, the Omnidirectional Delta Medial Axis (ODMA), with linear-time implementation to extract robust topology of the robot's local free space. It first introduces an adapted metric to cope with the deformations involved by the catadioptric sensor, and that is conformal with the ground 2D-metric. Then, it produces a pruned skeleton of the free space, inspired by the delta medial axis. Experimental results validate the approach for both skeleton precision and stability with respect to the robot position and free space topology.