Patent ID: 7110621

Claim:
A method for decoding image data for a hardcopy document, comprising: recording a scanned representation of the hardcopy document that includes a primary set of symbol data and a secondary set of encoding data; the primary set of symbol data providing a first channel of human readable information rendered on the hardcopy document; the secondary set of encoding data providing a second channel of machine readable information rendered on the hardcopy document; receiving a decoded form of the scanned representation of the hardcopy document from a decoding module to define a candidate set of symbol data; and rewriting, independent of the decoding module, the candidate set of symbol data using an event library and the secondary set of encoding data; and computing a shortest path of a product graph of the candidate set of symbol data and the secondary set of encoding data; the event library identifying likely failures encountered when the scanned representation of the hardcopy document is decoded; the event library comprising a rule that represents a transformation.