Implementation of data embedding to printing images for information retrieving by cellular phones considering lens distortion

Recently, several data extraction methods from data embedding printing images by using cellular phones with a camera have been proposed. In these techniques, consideration for geometrical deformation and lens distortion in the data extraction process is essential. This paper proposes new correction algorithm based on line based correction (LBR) and projective transformation to the scanning of the printing images for reduction of the geometrical deformation by the camera. This method can be applied to both of barrel distortion and pincushion one. To increase the amount of embedding data, a new data embedding method in which the codes for data embedding are changed according to the embedding data is also proposed. From experimental results, effectiveness of the proposed method for the color image is shown.