A first instance of a digital watermark may be embedded into an image. The first instance may encode information. A second instance of the digital watermark may be embedded into the image. The second instance may encode the information of the first instance. The second instance may be a sized differently or may be larger than the first instance.

One aspect of the present invention discloses a watermark embedding method in a watermark embedding apparatus. The method includes inputting a video frame, generating at least two tiles by spatially dividing the video frame, and embedding watermark information to each of the at least two tiles.

An example implementation includes an apparatus including a processor to divide a digital image into a grid including a first grid region and a second grid region. The processor is also to generate a first grid-based watermark using shared watermark information and a first set of grid coordinates associated with the first grid region. The processor is further to generate a second grid-based watermark using the shared watermark information and a second set of grid coordinates associated with the second grid region. The processor is further to embed the first grid-based watermark into a first region of the digital image corresponding to the first grid region and to embed the second grid-based watermark into a second region of the digital image corresponding to the second grid region. The processor is further to generate a machine-readable digital image including the embedded first grid-based watermark and the embedded second grid-based watermark.

An identification document including a multilayer laminate having a core layer defining an opening therethrough, and a dynamic window in the opening. The dynamic window includes an optically variable coating on at least a front or a back of the dynamic window. The optically variable coating appears transparent when viewed from the front of the identification document in light transmitted through the dynamic window from the back of the identification document toward the front of the identification document, and appears nontransparent when viewed from the front of the identification document in light reflected from the front of the identification document. Fabricating an identification document with a dynamic window includes forming an opening in a core layer, positioning a dynamic window in the opening, and plate laminating the core layer and the dynamic window between at least one outer layer on each side of the core layer.

Some implementations may include a computer-implemented method for applying at least two digital watermarks to a digital document, the method including: receiving a digital document comprising visual contents; generating a first digital watermark to be visually presented at a first time point; generating a second digital watermark to be visually presented at a second time point, the second digital watermark being different from the first digital watermark and the second time point being different from the first time point; and applying both the first digital watermark and second digital watermark to the digital document t.

An image processing method determines a geometric transform of a suspect image by efficiently evaluating a large number of geometric transform candidates in environments with limited processing resources. Processing resources are conserved by using configurations of dot product operations to produce both least squares mappings for each candidate and an error metric. Geometric transform candidates are rapidly winnowed to a smaller number of promising candidates based on the error metric and the promising candidates are refined further in subsequent iterations. An optimized method for determining updated coordinates for potential reference signal components in the suspect image evaluates a suspect image block at plural neighborhoods and builds a look up table that provides updated coordinates for each of the neighborhoods.

This application relates to the field of digital watermark technologies and discloses a digital watermark embedding method and extraction method, a digital watermark embedding apparatus and extraction apparatus, and a digital watermark system. The method includes obtaining a digital watermark of a composite file, splitting the digital watermark into N sub-watermarks according to a carrier quantity N of the composite file, each sub-watermark being corresponding to partial content of the digital watermark, embedding an i.sup.th sub-watermark in an i.sup.th carrier of the composite file, to obtain an i.sup.th target carrier, and integrating N target carriers into a target file. This application resolves a problem in the related technology that a digital watermark technology cannot ensure integrity of an order file, and protects carriers of a composite file, thereby ensuring security and integrity of the composite file.

Example systems disclosed herein to detect watermark modifications include a watermark encoder to encode a second watermark in a sampled media signal obtained from a received broadcast signal, the sampled media signal already encoded with a first watermark that was included in the received broadcast signal. Disclosed example systems also include a watermark decoder to detect the first watermark and the second watermark in the sampled media signal, and a watermark modification evaluator to compare a first metric determined for the first watermark and a second metric determined for the second watermark to determine whether the first watermark was modified prior to being included in the received broadcast signal. Disclosed example systems further include a ratings server to revise ratings data corresponding to the received broadcast signal when the first watermark is determined to have been modified prior to being included in the received broadcast signal.

Some implementations may include a method for watermarking an identification document, the method including: modulating a spatial luminance pattern associated with a first digital watermark to encode a first portion of personally identifiable information; modulating a spatial chrominance distribution associated with a second digital watermark to encode a second portion of the personally identifiable information; and applying the first digital watermark and the second digital watermark to the identification document.

A method and computer product for inserting additional frames into a .GIF file or modifying existing frames that can only be visible by recipients of the .GIF file satisfying a certain criteria are provided. A proprietary applications extension for .GIF file format allows for playing different images sequences within the same .GIF file to a recipient using a proprietary viewer application. The proprietary viewer application extension for .GIF file format allows for playing different image sequences in the .GIF viewer. A frame modification extension module contains sequence of images (in a binary form) and identifications that the proprietary .GIF viewer (with special extension logic) can substitute some of the GIF's image data while playing the file. Thus, the .GIF viewer is able to play different images (i.e., hidden embedded frames) than the ones played by a standard .GIF viewer to a certain recipient.