Transition Cells for Navigation and Planning in an Unknown Environment

We present a navigation and planning system using vision for extracting non predefined landmarks, a dead-reckoning system generating the integrated movement and a topological map. Localisation and planning remain possible even if the map is partially unknown. An omnidirectional camera gives a panoramic images from which unpredefined landmarks are extracted. The set of landmarks and their azimuths relative to a fixed orientation defines a particular location without any need of an external environment map. Transitions between two locations recognized at time t and t-1 are explicitly coded, and define spatio-temporal transitions. These transitions are the sensory-motor unit chosen to support planning. During exploration, a topological map (our cognitive map) is learned on-line from these transitions without any cartesian coordinates nor occupancy grids. The edges of this map may be modified in order to take into account dynamical changes of the environment. The transitions are linked with the integrated movement used for moving from one place to the others. When planning is required, the activities of transitions coding for the required goal in the cognitive map are enough to bias predicted transitions and to obtain the required movement.