By printing documents and other objects with machine readable indicia, such as
steganographic digital watermarks or barcodes, a great variety of document management
functions can be enabled. The indicia can be added as part of the printing process
(after document data has been output by an originating application program), such
as by printer driver software, by a Postscript engine in a printer, etc. The indicia
can encode data about the document, or can encode an identifier that references
a database record containing such data. By showing the printed document to a computer
device with a suitable optical input device (e.g., a webcam), an electronic version
of the document can be recalled for editing, or other responsive action can be taken.
