Patent ID: 7900848

Claim:
A process for tag imaging and decoding of machine readable coded data which comprises a plurality of layouts, each layout having at least order n rotational symmetry, where n is at least two, the layout encoding a first codeword comprising a sequence of at least n first symbols, the first symbols being distributed at n locations about a center of rotational symmetry of the layout such that decoding the first symbols at each of the n orientations of the layout produces n representations of the first codeword, each representation comprising a different cyclic shift of the first codeword and being indicative of the degree of rotation of the layout, and a second codeword comprising a number of second symbols, the second codeword being indicative of information regarding the respective layout, said process comprising: acquiring an image which includes said coded data; identifying at least one layout; decoding the layout to determine at least a representation of the first codeword; and determining a degree of rotation of the layout from the decoded representation.