Knowledge-based understanding of road maps and other line images

It is shown that the understanding of documents in general and of line drawings in particular can be seen as a first step towards the the understanding of arbitrary scenes by making effective use of methods from artificial intelligence. The starting point is a set of domain-independent linear image primitives which define a line graph. After the removal of artifacts the recognition of meaningful complex structures is accomplished in several steps with the aid of a growing amount of domain-specific knowledge. Further scene knowledge controls the deployment of the various operators to arrive at a consistent interpretation throughout the scene. The selection of the object-oriented programming paradigm proved to be very effective.<>