A system for document internal localization includes an optical input device for retrieving an observed region of a hardcopy document and a processing component which provides a location identifier for actionable observed regions by matching the retrieved region with a region of an electronically stored version of the hardcopy document. The hardcopy document and electronically stored version of the document include machine readable disambiguating information which has been added to actionable regions of the document which are indistinguishable from other actionable regions, based on their original markings, whereby a region is distinguishable from similar regions of the document. The disambiguating information is localized in regions of the document whose markings are not distinguishable without the disambiguating information.