A similarity retrieval method of drawings based on graph representation

An efficient method to retrieve necessary information from drawings for plant diagrams, logic circuit diagrams, etc. stored in a database is presented. In the image information retrieval systems currently in use, a keyword is assigned to each diagram and information is retrieved by the user by giving the keyword. When the features of the desired image are not registered as a keyword, however, its retrieval becomes difficult. In this paper a method is proposed in which the user shows features of the desired diagram using a sample diagram and a section similar to the sample diagram is retrieved. In this research, diagrams consisting mainly of symbols and connecting lines are considered. This kind of diagram is represented by a graph and similarities in topological features between the sample graph and graph representations of the diagrams in the database are evaluated. The retrieval is then performed based on the value obtained. The results of an experiment conducted using plant diagrams show that similar diagrams can be retrieved using this method.