US Patent 7234645 Document having an encoded data structure

A printed document includes a data structure encoded on a surface of at least one page of the document, the data structure comprising a plurality of block data regions. Each block data region includes: an encoded data region containing data in encoded form; a plurality of clock mark structures located on mutually opposite sides of the encoded data region; and a target structure located adjacent the clock mark structure. Each of the block data regions further includes an orientation data structure indicative of an orientation of the data structure.