Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Reinhard Zitzmann

Giovanni Del Galdo

Tobias Bliem

Juliane Borsum

Bert Greevenbosch

Stefan Kraegeloh

Joerg Pickel

Bernhard Grill

Ernst Eberlein

Stefan Wabnik

Marco Breiling

Stefan Krägeloh

Jörg Pickel

Giovanni Del Gardo

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.

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

A watermark generator for providing a watermark signal in dependence on binary message data includes an information processor configured to provide, in dependence on information units of the binary message data, a first time-frequency domain representation, values of which represent the binary message data. The watermark generator also includes a differential encoder configured to derive a second time-frequency domain representation from the first time-frequency-domain representation, such that the second time-frequency-domain representation includes a plurality of values, wherein a difference between two values of the second time-frequency-domain representation represents a corresponding value of the first time-frequency-domain representation, in order to obtain a differential encoding of the values of the first time-frequency-domain representation. The watermark generator also includes a watermark signal provider configured to provide the watermark signal on the basis of the second time-frequency-domain representation.

Watermark generator, watermark decoder, method for providing a watermark signal in dependence on binary message data, method for providing binary message data in dependence on a watermarked signal and computer program using a differential encoding

A watermark decoder includes a time-frequency-domain representation provider, a memory unit, a synchronization determiner and a watermark extractor. The time-frequency-domain representation provider provides a frequency-domain representation of the watermarked signal for a plurality of time blocks. The memory unit stores the frequency-domain representation of the watermarked signal for a plurality of time blocks. Further, the synchronization determiner identifies an alignment time block based on the frequency-domain representation of the watermarked signal of a plurality of time blocks. The watermark extractor provides binary message data based on stored frequency-domain representations of the watermarked signal of time blocks temporally preceding the identified alignment time block considering a distance to the identified alignment time block.

Watermark decoder and method for providing binary message data

A watermark signal provider comprises a time-frequency-domain waveform provider to provide time-domain waveforms for a plurality of frequency subbands. The time-frequency-domain waveform provider is configured to map a given value of a time-frequency-domain representation onto a bit shaping function, a temporal extension of which is longer than a bit interval, such that there is a temporal overlap between bit shaped functions provided for temporally subsequent values of the time-frequency-domain representation of the same frequency subband. A time-domain waveform of a given frequency subband contains a plurality of bit shaped functions provided for temporally subsequent values of the time-frequency-domain representation. The water mark signal provider further has a time-domain waveform combiner.

Watermark signal provider and method for providing a watermark signal

A watermark generator for providing a watermark signal in dependence on binary message data includes an information processor configured to provide, in dependence on a single message bit of the binary message data, a 2-dimensional spread information representing the message bit in the form of a set of time-frequency-domain values. The watermark generator also includes a watermark signal provider configured to provide the watermark signal on the basis of the 2-dimensional spread information. A watermark detector, methods and computer programs are also described.

Watermark generator, watermark decoder, method for providing a watermark signal in dependence on binary message data, method for providing binary message data in dependence on a watermarked signal and computer program using a two-dimensional bit spreading

A watermark signal provider provides a watermark signal suitable for being hidden in an audio signal when the watermark signal is added to the audio signal, such that the watermark signal represents watermark data. The watermark signal provider includes a psychoacoustical processor for determining a masking threshold of the audio signal; and a modulator for generating the watermark signal from a superposition of sample-shaping functions spaced apart from each other at a sample time interval of a time-discrete representation of the watermark data, each sample-shaping function being amplitude-weighted with a respective sample of the time-discrete representation, multiplied by a respective amplitude weight depending on the masking threshold, the modulator being configured such that the sample time interval is shorter than a time extension of the sample-shaping functions; and the respective amplitude weight also depends on samples of the time-discrete representation neighboring the respective sample in time.

Watermark signal provision and watermark embedding

A watermark generator for providing a watermark signal in dependence on binary message data, the watermark generator has an information spreader configured to spread an information unit to a plurality of time-frequency-domain values, to obtain a spread information representation. The watermark generator also has a synchronization inserter configured to multiplicatively combine the spread information representation with a synchronization sequence to obtain a combined information-synchronization representation. The watermark generator also has a watermark signal provider configured to provide the watermark signal on the basis of the combined information-synchronization representation. A watermark decoder, methods and computer programs are also described.

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Baiersdorf, Germany

Reinhard Zitzmann