Patent ID: 8498443

Claim:
A watermark information embedding device, comprising: a color component separator for separating an original image of a two-dimensional code into color components; a first wavelet transformer for performing, for each of the color components separated by the color component separator, a wavelet transform on the original image of the two-dimensional code to decompose this image into various frequency components; a watermark information embedder for embedding watermark information, as a high-frequency component in an oblique direction, in a high-frequency component in the oblique direction of the each of the color components out of the various frequency components decomposed by the first wavelet transformer with an embedding strength weighted in accordance with a usage frequency of the each of the color components in the original image of the two-dimensional code; an inverse wavelet transformer recomposing the two-dimensional code containing watermark information by performing an inverse wavelet transform on frequency components other than the high-frequency component in the oblique direction, out of the various frequency components decomposed by the first wavelet transformer, and the high-frequency component in the oblique direction in which the watermark information is embedded by the watermark information embedder; and a color component integrator for integrating the two-dimensional code containing watermark information for the each of the color components recomposed by the inverse wavelet transformer.