A method and apparatus for encoding and detecting data which can be represented in a physical array of modules recorded on a medium. Information is encoded in "image-blocks". An image-block comprises a plurality of "sub-blocks". Sub-blocks comprise a plurality of "modules". A module is...http://www.google.com.au/patents/US5778011?utm_source=gb-gplus-sharePatent US5778011 - Method and apparatus for writing and protecting against random and cluster errors in image blocks 
