A knowledge-based graphic description tool for understanding engineering drawings

A knowledge-based graphic description tool (KGDT) that is used to recognize and understand engineering drawings is described. This tool basically consists of a concept description network, a graphic description language, a physical description framework, a set of image processing modules, a matcher, a rule-based inference engine, an interpreter, and a blackboard control architecture. The matcher recognizes all graphic symbols and characters in the engineering drawing based on the various properties of the different graphic symbols and characters that are extracted by the low-level image processing routines. The rule-based inference engine is built to infer possible relations among graphic symbols and generate a relational graph. The interpreter is used to generate an acceptable explanation in terms of traversal of the relational graph. The interactions among the interpreter, the matcher, the inference engine, and the image processing routines are controlled by the blackboard control architecture