To provide a variety of methods for extracting digital watermark information from an image as correctly as possible. For example, a first pattern arrangement and a second pattern arrangement which is different from the first pattern arrangement for use in a calculation for extracting the digital watermark information are provided. A state of an original image without the digital watermark information embedded is inferred, using a second pattern arrangement, and a reliability of the digital watermark information to be extracted in accordance with the state is determined. Or to decide the embedding position of the digital watermark information from the image data, the extracting start position is discriminated by detecting the positional information by multiple times at the different extracting start positions. Or to detect a geometrical distortion, a registration signal is embedded on the image.