Patent ID: 7187782

Claim:
A digital watermark-embedding apparatus comprising: a characteristic amount-calculating unit operable to calculate a characteristic amount of a digital image; an embedment intensity-determining unit operable to determine an embedment intensity using the characteristic amount calculated by said characteristic amount-calculating unit and a compression bit rate for use in encoding; a digital watermark-embedding unit operable to embed a digital watermark into the digital image at the embedment intensity determined by said embedment intensity-determining unit; and an image-encoding unit operable to encode, by using the compression bit rate, the digital image having the digital watermark embedded therein by said digital watermark-embedding unit, so as to provide a compressed bit stream, wherein: said characteristic amount-calculating unit is operable to calculate a characteristic amount for each local region, respectively, that forms part of the digital image; and the characteristic amount for each local region is a sum of an average value of luminance components over the local region and differential absolute values of horizontally neighboring pixels and differential absolute values of vertically neighboring pixels over the same local region.