Patent ID: 8107733

Claim:
A system for imaging a coding pattern disposed on a surface of a substrate, said system comprising: (A) said substrate, wherein said coding pattern comprises: a plurality of contiguous square tags of length l, each tag comprising x-coordinate data and y-coordinate data, wherein a y-axis is nominally defined as north-south and an x-axis is nominally defined as east-west; and a plurality of data elements contained in each tag, said x-coordinate data being represented by a respective set of data elements and said y-coordinate data being represented by a respective set of data elements, wherein: said x-coordinate data comprises a replicated part and a non-replicated part, said replicated part having a first replication in a western half of said tag and a second replication in an eastern half of said tag, and said non-replicated part being represented in a central column of said tag, said central column dividing said western half from said eastern half; said y-coordinate data comprises a replicated part and a non-replicated part, said replicated part having a first replication in a northern half of said tag and a second replication in a southern half of said tag, and said non-replicated part being represented in a central row of said tag, said central row dividing said northern half from said southern half; and said central column and said central row each have a width q; and (B) an optical reader comprising: an image sensor for capturing an image of a portion of said coding pattern, said image sensor having a field-of-view of at least (l+q)√2 and less than (2l)√2; and a processor configured for performing the steps of: (i) sampling and decoding x-coordinate data and y-coordinate data contained in an imaged portion; and (ii) determining a position of said optical reader.