Watermark Signal Provider Using Temporal Overlap
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Solution Overview
Problem
Existing watermarking systems face challenges in maintaining robustness and detectability due to low energy waveforms, leading to bit errors and reduced reliability, especially in noisy environments.
Innovation Solution
A watermark signal provider that utilizes a time-frequency domain representation to create a waveform with temporal overlap between bit shaped functions for the same frequency subband, increasing redundancy and robustness without increasing the energy of the watermark signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If low energy waveforms are used in watermarking systems, then the watermark signal remains inaudible and imperceptible, but the detectability and robustness of the watermark signal deteriorate, leading to bit errors
Solution Approach 1:
The patent applies periodic action by using overlapping bit-shaped functions that extend beyond individual bit intervals. Each bit-shaped function has a temporal extension longer than the bit interval, creating periodic overlaps between consecutive bits. This periodic overlapping structure allows the signal to maintain low energy levels while improving detectability through correlation between overlapping portions, thereby resolving the contradiction between inaudibility and robustness.
Solution Approach 2:
The patent implements preliminary action by pre-defining the temporal overlap structure of bit-shaped functions before signal generation. The bit-shaped functions are designed with predetermined temporal extensions that create overlapping regions, allowing the decoder to anticipate and correlate these overlaps. This preliminary structuring enables robust detection without requiring higher energy levels, thus maintaining both inaudibility and reliability.
2Reliability
If bit shaped functions have temporal extension longer than bit interval, then redundancy and robustness increase, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the watermark signal into discrete bit-shaped functions, each corresponding to a specific bit interval. Each segment (bit-shaped function) is independently generated and then overlapped with adjacent segments. This segmentation allows for modular processing and simplifies the generation process, as each bit-shaped function can be created using standard modulation techniques, thereby reducing overall device complexity while maintaining robustness through the overlapping structure.
Solution Approach 2:
The patent implements dynamics by making the bit-shaped functions adaptable to different bit intervals and frequency subbands. The temporal extension of each bit-shaped function is dynamically adjusted based on the bit interval and frequency characteristics. This dynamic adjustment allows the system to optimize robustness for different conditions without requiring a completely complex fixed structure, thus balancing reliability improvement with device complexity management.
Data Source
AI summary
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.