1. A system that recognizes embedded interaction code (EIC) symbols, the system comprising: an EIC-dot-detection module that takes effective EIC symbols, which have been generated by processing an image containing the EIC symbols, as input and produces EIC dots as output by obtaining graylevels of selected positions of the EIC symbols; an EIC-symbol-orientation-determination module that takes the EIC dots as input and produces rotated EIC dots as output by determining which grid cells correspond to the EIC symbols and by determining which direction is a correct orientation of the EIC symbols; and an EIC-bit-extraction module that takes the rotated EIC dots as input and produces EIC bits as output based on graylevels of selected positions of the rotated EIC dots.