7. The method according to claim 6 , wherein the layout information is used to identify underlying PDF or XPS content.
6. The method according to claim 1 , wherein the identification process includes a first step of layout matching, which uses 2D visual fingerprints to identify matching locations in the source document and the revised document, the layout analysis being used to narrow down the candidate matches; and a second step of text scoring to determine a method of highlighting the changes.