Patent ID: 8023746

Claim:
A method of decoding an image of a pattern on an object to determine a digital identifier, the method comprising: (a) receiving an image of a pattern on the object, the image comprising a plurality of pixels, each of the pixels having an optical attribute with a corresponding value; (b) dividing the image into a plurality of tiles, each of the tiles comprising a contiguous plurality of the pixels of the image; (c) defining a plurality of ranges of the value of the optical attribute; (d) for each of the pixels in each of the tiles: determining the value of the optical attribute of the pixel, and determining which of the ranges corresponds to the value of the optical attribute of the pixel; (e) assigning a digital bit to each of the tiles based on the range corresponding to the largest number of values of the optical attribute of the pixels in the tile; and (f) determining a digital identifier based on the digital bits assigned to the tiles.