Patent ID: 7032823

Claim:
A two-dimensional code comprising: a plurality of unit cells arranged in two-dimension, each of said unit cells indicating one of at least three colors, each color of each of said unit cells being optically readable and representing a data value set to each of the unit cells; and a specifying pattern portion including a plurality of color reference cells and configured to specify positions of the unit cells, said color reference cells indicating all of the at least three colors, wherein said unit cells and color reference cells are arranged substantially in a matrix configuration, said plurality of color reference cells include first color reference cells, said specifying pattern portion includes a first specifying pattern that includes the first color reference cells, said first specifying pattern is disposed to one of peripheries of the matrix configuration, said at least three colors include a first color and a second color having a predetermined contrast level to be optically identifiable between each other, said first and second colors are individually assigned to the first color reference cells in accordance with a predetermined ratio between the first color and second color, and said predetermined ratio is optically readable independent of reading directions along the two-dimension.