Watermark Generator Multiplicative Synchronization
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Solution Overview
Problem
Existing watermarking systems face challenges in achieving efficient synchronization between the watermark generator and decoder, often requiring high resource effort and experiencing reliability issues due to difficulties in acquiring appropriate synchronization.
Innovation Solution
A watermark generator that multiplicatively combines a spread information representation with a synchronization sequence, allowing for simultaneous transmission of message data and synchronization information at identical frequencies, ensuring rapid and reliable synchronization without distorting the useful signal content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional watermarking systems use separate transmission of synchronization information and message data, then synchronization reliability can be improved, but device complexity and resource effort increase
Solution Approach 1:
The patent combines synchronization information and message data into a single watermark signal transmission channel. The watermark generator embeds both types of information simultaneously in the audio signal, eliminating the need for separate transmission paths. This merging reduces system complexity while maintaining synchronization reliability through the use of correlation-based detection that can distinguish between synchronization patterns and message data.
Solution Approach 2:
The watermark signal serves multiple functions simultaneously: it carries synchronization information for timing alignment and message data for content identification. The universal watermarking approach allows the same embedded signal to perform both synchronization and data transmission roles, reducing the need for separate dedicated synchronization channels and lowering overall system complexity.
2Loss of information
If watermarking systems embed extra information into audio data, then information capacity increases, but audio signal distortion increases
Solution Approach 1:
The patent employs spread spectrum modulation techniques that distribute the watermark energy across a wide frequency range. By changing the spectral parameters and using pseudo-random sequences, the watermark signal is embedded at low amplitude levels across many frequency bins, making it imperceptible to human hearing while maintaining high information capacity. The correlation-based detection compensates for the low individual amplitude through coherent integration.
3Measurement precision
If synchronization is acquired through traditional methods, then synchronization accuracy can be improved, but time consumption and resource effort increase
Solution Approach 1:
The patent embeds known synchronization patterns at predetermined positions within the watermark signal structure. The decoder uses correlation detection with these pre-known patterns to rapidly acquire synchronization without requiring extensive search or adjustment. This preliminary embedding of synchronization markers enables fast and accurate timing alignment.
Solution Approach 2:
The patent replaces traditional mechanical or sequential synchronization acquisition methods with a correlation-based detection system. Instead of incrementally adjusting timing and checking for alignment, the system uses mathematical correlation between the received signal and expected synchronization patterns to directly determine the correct timing offset, significantly reducing acquisition time and computational resources.
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AI summary
A watermark generator (2400) for providing a watermark signal (2420) in dependence on binary message data (2410), the watermark generator comprises an information spreader (2430) configured to spread an information unit to a plurality of time-frequency-domain values, to obtain a spread information representation (2432). The watermark generator also comprises a synchronization inserter configured to multiplicatively combine the spread information representation (2432) with a synchronization sequence (2442) to obtain a combined information-synchronization representation (304a, So cf . m; 2444). The watermark generator also comprises a watermark signal provider (2450) configured to provide the watermark signal (2420) on the basis of the combined information-synchronization representation (2444). A watermark decoder, methods and computer programs are also described.