Purdue Research Foundation

Digimarc Corporation

Eugene Ted Lin

Edward John Delp

Adnan M Alattar

Mehmet Utku Celik

Jordan J Glogau

Raymond B Wolfgang

Methods for embedding digital watermarks in compressed video include perceptual adapting a digital watermark in predicted and non-predicted data based on block activity derived from the compressed video stream, embedding in predicted objects in a video stream having separately compressed video objects, and bit rate control of watermarked video.

Digital watermarking of low bit rate video

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.

Synchronization of digital watermarks

A protocol for temporal synchronization of media signals with temporal components is used for digital watermarking and other applications. The synchronization protocol achieves initial synchronization by finding an initial synchronization key through analysis of a temporal media signal stream. It then uses features of the stream and a queue of one or more keys from previous frames to derive subsequent keys to maintain synchronization. If synchronization is lost due to channel errors or attacks, for example, the protocol uses the initial synchronization key to re-establish synchronization. In digital watermarking applications, the synchronization protocol is agnostic to the watermark embedding and reading functions.

Temporal synchronization of video and audio signals

A method for synchronization of a media signal computes features of the media signal and determines redundancy of the features to establish synchronization. The synchronization method is adapted for both temporal and spatial synchronization. For spatial synchronization, spatial redundancy is used to detect geometric distortion of a signal using an autocorrelation method to detect peaks caused by the redundancy of features of the signal. 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 for both intra-coded frames of video (I-frames) as well as still images.

Synchronization of media signals

A method of data hiding includes providing a message (), providing an encrypting sequence (), and generating an encrypted message () based on the message and the encrypting sequence. A carrier signal () that conveys information unrelated to the encrypted message is provided, and the encrypted message is embedded () into the carrier signal by performing an exclusive-OR of the encrypted message with a first portion of the carrier signal.

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West Lafayette, IN, United States of America

Eugene Ted Lin