On Tuesdays the USPTO issues new patents. Both of today's Spotlight patents entail the use of watermarking. Assigned to Boeing, the first patent concerns a dynamic wavelet feature-based watermark. Assigned to Digimarc, the second patent concerns digital watermarking with content dependent keys and autocorrelation properties for synchronization
On 7,366,909, "Dynamic wavelet feature-based watermark," assigned to Boeing.
A dynamic wavelet feature-based watermark for use with digital video. Scene change detection separates digital data into one or more scenes, wherein each of the scenes is comprised of one or more frames. A temporal wavelet transformation decomposes the frames of each scene into dynamic frames and static frames. The static frames of each scene are subjected to a spatial wavelet transformation, so that the watermark can be cast into middle frequency sub-bands resulting therefrom. Polyphase-based feature selection or local block-based feature selection is used to select one or more features. The watermark is cast into the selected features by means of either (1) a comparison of energy in polyphase transform components of the selected feature, or (2) a change in value of blocked wavelet coefficients of the selected feature.
7,366,908, "Digital watermarking with content dependent keys and autocorrelation properties for synchronization," assigned to Digimarc.
A digital watermark detection method exploits autocorrelation properties of the watermarked signal that enable synchronization of the digital watermark despite temporal or geometric distortion of the host signal. Other watermark methods employ keys, including a key dependent on the content in which the watermark is embedded and another key that is not dependent on the content.