1. A method of obtaining information included in an image, the image including a plurality of codes, each of the codes comprising a plurality of digits, the method comprising: dividing the image into a plurality of pairs of blocks; determining a digit value of each of the block pairs on the basis of difference of a degree of characteristic value between adjacent blocks in each of the pairs; weighing each digit value of each of the block pairs; deciding a new digit value of associated pairs of blocks on the basis of the majority of the weighed digit values of the associated pairs of the blocks; and repeating the deciding in other associated pairs of the blocks to determine said code.