Spectral Well Creation for Audio Watermark Extraction
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Solution Overview
Problem
Existing audio watermarking systems face challenges in decoding watermarks due to insufficient signal-to-noise ratio (S/N) caused by high energy levels in the audio signal at the frequency band where the watermark is inserted, which impairs the decoder's ability to effectively detect the watermark.
Innovation Solution
Creating spectral wells by reducing the energy of the audio signal in the frequency band where the watermark is inserted to enhance the S/N ratio, allowing for better watermark detection by the decoder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the energy of the audio signal is maintained at high levels in the frequency band where the watermark is inserted, then the audio signal quality is preserved, but the signal-to-noise ratio (S/N) becomes insufficient for the decoder to successfully extract the watermark
Solution Approach 1:
The patent applies local quality by creating spectral wells specifically in the frequency bands where watermarks are inserted, while leaving other frequency bands unchanged. This localized energy reduction in specific spectral regions allows the decoder to successfully extract watermarks without degrading the overall audio signal quality, as only targeted frequency regions are modified rather than the entire audio spectrum.
Solution Approach 2:
The patent segments the audio spectrum into different frequency bands and selectively modifies only those bands where watermarks are present. By dividing the frequency spectrum and applying energy reduction only to specific segments containing watermark information, the system improves watermark detectability while preserving the integrity of the rest of the audio signal.
2Measurement precision
If spectral wells are created by reducing audio signal energy in the watermark frequency band, then the signal-to-noise ratio (S/N) is improved for watermark detection, but the audio signal energy is reduced
Solution Approach 1:
The spectral well creation process applies energy reduction locally only in frequency bands containing watermark information, preserving the quality and energy of other audio frequency bands. This localized approach improves watermark detection accuracy in specific regions without causing significant overall energy loss in the audio signal.
Solution Approach 2:
The patent converts the potentially harmful effect of high audio signal energy (which masks watermarks and reduces S/N ratio) into a benefit by strategically reducing energy only in watermark-containing frequency bands. This targeted energy reduction transforms the original problem into a solution, improving watermark detectability while minimizing impact on overall audio quality.
Data Source
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AI summary
A method for a machine or group of machines to watermark an audio signal may include receiving the audio signal, receiving a watermark signal, creating a spectral well on the audio signal by removing a portion of the audio signal corresponding to a frequency range, and inserting the watermark signal in the spectral well.