Scene Understanding of Urban Road Intersections with Description Logic

Road recognition from video sequences has been solved robustly only for small, often simplified subsets of possible road configurations. A massive augmentation of the amount of prior knowledge may pave the way towards a generation of estimators of more general applicability. This contribution introduces Description Logic extended by rules as a promising knowledge representation formalism for road and intersection understanding. We have set up a Description Logic knowledge base for arbitrary road and intersection geometries and configurations. Logically stated geometric constraints and road building regulations constrain the hypothesis space. Sensor data from an in-vehicle vision sensor and from a digital map provide evidence for a particular intersection. Partial observability and different abstraction layers of the input data are naturally handled by the representation formalism. Deductive inference services – namely satisfiability, classification, entailment, and consistency – are then used to narrow down the intersection hypothesis space based on the evidence and the background knowledge, and to retrieve intersection information relevant to a user, i.e. a human or a driver assistance system. We conclude with an outlook towards non-deductive reasoning, namely model construction under the answer set semantics.