ENHANCED COMPRESSION OF DOCUMENTS

Increased and potentially extreme compression of documents is achieved by reducing/remapping the dynamic range of the document image possibly together with further image analysis and pre-processing and storing the document together with a substituted table of values chosen to restore or enhance the dynamic range of the document image. Increased or extreme compression is provided notwithstanding multiple image tones (e.g. colors or grey scale levels) even at low contrast within a document, such as a personal check. Such increased compression allows document images to be maintained in rapid-access memory for extended periods without increased storage costs.