A digital watermark embedding apparatus for embedding digital watermark
information by superimposing macroblock patterns on an image is
disclosed. The digital watermark embedding apparatus: spreads input
digital watermark information to obtain an embedding series having a
length corresponding to a number of pixel blocks of a macroblock pattern;
selects at least a frequency from among predetermined plural frequencies
according to a term value of the embedding series corresponding to a
position of a pixel block in the macroblock pattern, and sets a waveform
pattern corresponding to the selected frequency as a pixel of the pixel
block; and amplifies, with an embedding strength value, the macroblock
pattern on which a waveform pattern is superimposed on each pixel block
by the waveform pattern setting unit, and superimposes the macroblock
pattern on an input image like a tile.