Locating indexing structures in engineering drawing databases using location hashing

Fast and robust localization of image regions that are likely to come from a query object is a critical operation needed in several image database applications. In this paper, we address this problem in the context of locating indexing structures in engineering drawing databases. Specifically, we present a general 2d pattern localization technique called location hashing and apply it to the problem of localizing title block structures in engineering drawings. Location hashing is a variation of geometric hashing that directly identifies locations in images of a database that are likely to contain a query object, possibly depicted under different imaging conditions. We also describe an engineering drawing indexing system that combines title block localization with text recognition to enable automatic index creation of engineering drawing databases.