Patent ID: 8204271

Claim:
A digital watermark detecting apparatus comprising: a scaling unit configured to enlarge or contract an input image signal having N kinds of embedded information embedded therein at N kinds of different enlargement ratios or contracting ratios to generate N kinds of scaled images, wherein N>1; an extractor configured to generate N kinds of extracting signals by extracting specific frequency component signals respectively from the N kinds of scaled images; a first orthogonal transformer configured to perform an orthogonal transform on the input image signal to generate a first transforming signal; a second orthogonal transformer configured to perform the orthogonal transform on the N kinds of extracted signals respectively to generate N kinds of second transforming signals; a synthesizer configured to synthesize the first transforming signals and the N kinds of second transforming signals respectively to generate N kinds of synthesized images; a third orthogonal transformer configured to perform the orthogonal transform or inverted orthogonal transform on the N kinds of synthesized images respectively to generate N kinds of third transforming signals; and an estimator configured to estimate the N kinds of embedded information from peaks appearing in the N kinds of third transforming signals.