Spread Spectrum Audio Watermarking in Noisy Automotive Environments
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Solution Overview
Problem
Existing audio watermarking techniques face difficulties in noisy environments, such as automobiles, where ambient noise interferes with the detection of embedded watermarks, making it challenging to discern the watermark from noise.
Innovation Solution
The implementation of spread spectrum techniques within automotive systems, including the use of pseudorandom codes and adaptive filtering, allows for the embedding and decoding of watermarks within audio signals, ensuring they remain inaudible while maintaining a constant signal-to-noise ratio, even in noisy conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spread spectrum techniques are used to embed watermarks in audio signals, then the watermark remains inaudible to human listeners, but the watermark becomes difficult to detect in noisy environments such as automobiles
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the watermark amplitude and frequency characteristics based on the ambient noise level detected in the automotive environment. The system modifies the watermark signal parameters in real-time to maintain detectability while remaining inaudible, resolving the contradiction between watermark stealth and detection reliability in noisy conditions
Solution Approach 2:
The system implements feedback mechanisms where the detected ambient noise level is continuously monitored and used to adjust the watermark embedding strength and characteristics. This closed-loop approach allows the system to adapt to changing noise conditions in the automobile environment, maintaining both inaudibility and detectability of the watermark
2Measurement precision
If the watermark amplitude is increased to improve detection in noisy environments, then the watermark becomes more detectable, but it may become audible to listeners
Solution Approach 1:
The patent applies local quality by embedding the watermark in specific frequency regions of the audio signal where the human auditory system is less sensitive. By targeting particular spectral regions rather than distributing the watermark uniformly across all frequencies, the system achieves better detection accuracy while maintaining inaudibility, even in noisy automotive environments
3Object-affected harmful factors
If ambient noise in the automobile is used to mask the watermark, then the watermark remains inaudible, but the watermark becomes indistinguishable from the noise
Solution Approach 1:
The patent introduces an intermediary spread spectrum code that acts as a carrier for the watermark information. This code spreads the watermark signal across a wide frequency spectrum, creating a distinctive pattern that can be correlated at the receiver to extract the embedded information even in the presence of ambient automotive noise, thus maintaining both inaudibility and information integrity
Data Source
AI summary
A method of operating an audio system in an automobile includes identifying a user of the audio system. An audio recording playing on the audio system is identified. An audio setting entered into the audio system by the identified user while the audio recording is being played by the audio system is sensed. The sensed audio setting is stored in memory in association with the identified user and the identified audio recording. The audio recording is retrieved from memory with the sensed audio setting being embedded in the retrieved audio recording as a watermark signal. The retrieved audio recording is played on the audio system with the embedded sensed audio setting being automatically implemented by the audio system during the playing.