Patent ID: 7047412

Claim:
A digital watermark embedding method for embedding digital watermark data to content data, comprising: a preliminary process step for applying an embeddability analyzing process to content data before embedding digital watermark data to the content data, compiling an embedding strength map for each part of the content data, and storing said embedding strength map with correlation to the content data, said embedding strength map indicating, for each said part of the content data, an allowed change in a feature value of said part, said allowed change being the change in the feature value allowed for embedding a bit of a bit sequence representing the digital watermark data in said part; and a main process for embedding the digital watermark data in the content data by, for each bit of the bit sequence representing the digital watermark data, changing the feature value of a part in the content data determined according to predetermined rules by an amount determined according to the bit value of said bit and the allowed change in the feature value of said part indicated by the embedding strength map stored for the particular content data; wherein the main process is accomplished separately from the preliminary process for each of plural different digital watermark data.