Relational skeletons for retrieval in patent drawings

This paper presents the evaluation of a number of algorithm alternatives for content based retrieval from a database of technical drawings representing patents. The objective is to help patent evaluators in their quest for a possible patent bearing too much similarity with the one under investigation. To achieve this, we have devised a system where images (drawings) are represented using attributed graphs based on the extracted line-patterns or histograms of attributes computed from the graphs. Retrieval is either performed using histogram comparison (see Huet, B. and Hancock, E.R., PAMI, vol.21, no.12, p.1363-70, 1999) or thanks to a graph similarity measure (see Huet and Hancock, CVPR, p.138-43, 1998). Promising results are presented along with possible work extension.