Enriching a document collection by integrating information extraction and PDF annotation

Modern digital libraries oer all the hyperlinking possibilities of the World Wide Web: when a reader nds a citation of interest, in many cases she can now click on a link to be taken to the cited work. This paper presents work aimed at providing the same ease of navigation for legacy pdf document collections that were created before the possibility of integrating hyperlinks into documents was ever considered. To achieve our goal, we need to carry out two tasks: rst, we need to identify and link citations and references in the text with high reliability; and second, we need the ability to determine physical pdf page locations for these elements. We demonstrate the use of a high-accuracy citation extraction algorithm which signicantly improves on earlier reported techniques, and a technique for integrating pdf processing with a conventional text-stream based information extraction pipeline. We demonstrate these techniques in the context of a particular document collection, this being the acl Anthology; but the same approach can be applied to other document sets.