Apparatus, method, and program product for detecting digital watermark

A digital watermark detection apparatus detects a watermark value from a motion image in which a topological invariant is embedded as the watermark value. The digital watermark detection apparatus includes a watermark component extracting unit which extracts each watermark component from the motion image; an average value computing unit which computes an average value of component values of pixels included in the watermark component; an identified watermark component determination unit which determines whether or not the watermark component is an identified watermark component to be utilized in identifying an arrangement unit of a plurality of watermark components based on the average value; a watermark component identifying unit which identifies the watermark component except for the identified watermark component; and a watermark value computing unit which computes the watermark value based on the identified watermark component and the watermark components except for the identified watermark component.