On Tuesdays the USPTO issues new patents. Both of today's Spotlight Patents concern aspects of digital watermarking. Assigned to Purdue Research Foundation, the first patent addresses techniques for the synchronization of digital watermarks. Assigned to IBM, the second patent addresses techniques for watermark hiding in designated applications.
8,370,635, "Synchronization of digital watermarks," assigned to Purdue Research Foundation
A method for synchronization of a digital watermark generates a digital watermark based on feature extraction and a key generator. The synchronization method is adapted for both temporal and spatial synchronization. Statistical features of the watermarked signal along with key generators are used to compute keys used to detect embedded digital watermarks that vary over time or space. For spatial synchronization, spatial redundancy is used to detect geometric distortion of a signal in which the watermark is embedded using an autocorrelation method to detect peaks caused by the redundancy of the watermark structure. These peaks are then analyzed with a histogram method to detect rotation and scaling of the host media signal. The spatial synchronization process is applied to watermarks for both intra-coded frames of video (I-frames) as well as still images.
8,363,884, "Watermark hiding in designated applications," assigned to IBM.
A method, service, and product for hiding a watermark existing in a digital media within a software application, comprising creating a set pattern of pixels represented by coordinates which represent a red, a green, a blue, and an alpha level of color, where the set pattern of pixels covers a set of original pixels within the digital media. The method including determining whether the transparency level of color should be removed from the set pattern of pixels based on a known pixel transparency removal parameter; and modifying the set pattern of pixels to remove the transparency level of color coordinates, wherein an original pixel color can be seen because the set pattern of pixels are made transparent; or not modifying the set of pixels to remove the transparency level of color coordinates, wherein the original pixel color cannot be seen because the set of original pixels is made transparent.