New patents are issued by the USPTO on Tuesdays. Both of today's Spotlight Patents concern aspects of digital watermarking. Assigned to Digimarc, the first of today's patents addresses techniques for multi-mode audio recognition and auxiliary data encoding and decoding. Assigned to CNRS and the Universite De Nantes (FR), the second patent concerns techniques for inserting, in the fourier domain, a digital watermark in an image and corresponding method for detecting a digital watermark in an image to be analyzed.
9,401,153, "Multi-mode audio recognition and auxiliary data encoding and decoding," assigned to Digimarc.
Abstract
Audio signal processing enhances audio watermark embedding and detecting processes. Audio signal processes include audio classification and adapting watermark embedding and detecting based on classification. Advances in audio watermark design include adaptive watermark signal structure data protocols, perceptual models, and insertion methods. Perceptual and robustness evaluation is integrated into audio watermark embedding to optimize audio quality relative the original signal, and to optimize robustness or data capacity. These methods are applied to audio segments in audio embedder and detector configurations to support real time operation. Feature extraction and matching are also used to adapt audio watermark embedding and detecting.9,401,002, "Method for inserting, in the fourier domain, a digital watermark in an image and corresponding method for detecting a digital watermark in an image to be analyzed," assigned to the Centre National De La Recherche Scientifique--CNRS (FR) and the Universite De Nantes (FR).
Abstract
A method is provided for inserting a digital watermark in an image by an insertion device. Inserting includes: applying a Fourier transform to the image, delivering a 2D Fourier spectrum; inserting the watermark in the Fourier spectrum delivering a modified Fourier spectrum; and applying an inverse Fourier transform to the modified Fourier spectrum delivering a watermarked image. The watermark includes a set of watermarking coefficients each associated with a distinct determined position of a given quadrant among the quadrants of the Fourier domain, the spectral coordinates u and v of which, measured along the two axes of coordinates of the given quadrant and starting from the continuous component and expressed in percentage of the dimensions U and V of the given quadrant, are such that: u>66%.times.U and v>66%.times.V. The set of positions associated with the watermarking coefficients defines a convex pattern in the given quadrant.
