Watermark generator, watermark decoder, method for providing a watermarked signal based on discrete valued data and method for providing discrete valued data in dependence on a watermarked signal

US9514500B2 · kind B2 · utility

Assignee

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE

Inventors

• Reinhard Zitzmann · Effeltrich, DE
• Giovanni Del Galdo · Martinroda, DE
• Tobias Bliem · Erlangen, DE
• Juliane Borsum · Erlangen, DE
• Bert Greevenbosch · Rotterdam, NL
• Stefan Kraegeloh · Erlangen, DE
• Joerg Pickel · Happurg, DE

Key dates

• Filing date: Mar 21, 2013
• Grant date: Dec 6, 2016
• Expiry date: May 24, 2034

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N21/8358
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

A watermark generator for providing a watermark signal as a sequence of subsequent watermark coefficients based on a stream of subsequent stream values representing discrete valued data includes a differential encoder. The differential encoder is configured to apply a phase rotation to a current stream value of the stream values representing the discrete valued data or to a current watermark symbol, the current watermark symbol corresponding to a current stream value of the stream values representing the discrete valued data, to obtain a current watermark coefficient of the watermark signal. The differential encoder is configured to derive a phase of a previous spectral coefficient of a watermarked signal which is a combination of the host signal and the watermark signal, and to provide the watermark signal such that a phase angle of the phase rotation applied to the current stream value or the current watermark symbol is dependent on the phase of the previous spectral coefficient of the watermarked signal.