Grammars and Discourse Theory to Describe and Recognize Mechanical Assemblies

In recent years numerous approaches to automatic reasoning about mechanical assemblies have been published. CAD techniques, graph-based approaches and semantic methods to model assembled objects were proposed. However, all these methods are difficult to employ for visually supervising assembly processes since they lack the flexibility, generality or ease required in practice. This paper presents the idea of using syntactic methods known from discourse theory in order to model classes of mechanical assemblies. Moreover, a criterion to derive recursive grammatical production rules is introduced so that the representation of a class of assemblies becomes especially compact. This general representation scheme allows to automatically derive hierarchical structural descriptions of individual assemblies by means of computer vision.