Patent ID: 7724917

Claim:
A digital watermark detection apparatus, which detects a watermark value from a motion image in which a topological invariant is embedded as the watermark value, the apparatus comprising: a watermark component extracting unit which extracts each watermark component from the motion image in which the watermark value is embedded, where the watermark value includes a plurality of different watermark components arranged according to a predetermined arrangement regularity; an average value computing unit which computes an average value of component values of each pixel included in the watermark component; an identified watermark component determination unit which determines, based on the average value, whether or not the watermark component is a determined identified watermark component which is to be utilized in identifying an arrangement unit of a plurality of watermark components included in the same watermark value within the plurality of watermark components included in the watermark value; a watermark component identifying unit which identifies each watermark component except for the determined identified watermark component based on the identified watermark component and the arrangement regularity, where the each watermark component is included in the watermark value; and a watermark value computing unit which computes a watermark value based on the determined identified watermark component and the watermark components identified by the watermark component identifying unit.