Frequency-Masked Audio Watermarking for Imperceptible Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing media monitoring systems face challenges in efficiently and imperceptibly embedding and extracting audio watermarks to track media consumption and control device behavior, particularly in environments where audio signals are reproduced.
Innovation Solution
The system employs an encoder to insert inaudible audio watermarks into media signals using frequency masking techniques, and a decoder to recover these watermarks for tracking and control purposes, utilizing methods like discrete Fourier transformation and error correction to ensure robust extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If audio watermarks are embedded into media signals using frequency masking techniques, then the tracking and control capability is improved, but the audio signal may become distorted or the watermark may become audible
Solution Approach 1:
The system dynamically adjusts watermark embedding parameters including frequency selection, amplitude modulation depth, and temporal distribution based on the host audio signal characteristics. The encoder analyzes the audio signal in real-time and modifies watermark parameters to ensure imperceptibility while maintaining detectability, resolving the contradiction between reliable tracking and audio quality preservation
Solution Approach 2:
The watermark embedding process is made adaptive and dynamic rather than static. The system continuously monitors audio signal properties and adjusts watermark strength, frequency position, and temporal placement accordingly. This dynamic adaptation allows the system to maintain reliable tracking capability while preventing audible artifacts and distortion across varying audio content
2Reliability
If complex error correction and synchronization techniques are applied to watermark extraction, then the extraction reliability is improved, but the device complexity increases
Solution Approach 1:
Error correction codes and synchronization patterns are pre-encoded into the watermark signal during the embedding process. Synchronization words and error correction data are inserted in advance at known positions, allowing the decoder to quickly acquire and verify watermark presence without complex real-time analysis, thus improving extraction reliability while limiting complexity growth
Solution Approach 2:
The system uses redundant copying of synchronization patterns and error correction data throughout the watermark sequence. Multiple copies of critical information are embedded at different time positions and frequency locations, enabling the decoder to recover the watermark even if some portions are lost or corrupted, thereby improving reliability without requiring overly complex decoding algorithms
3Measurement precision
If audio watermarks are embedded at high amplitude to ensure detectability, then the detection precision is improved, but the watermark becomes audible and distorts the original audio
Solution Approach 1:
The watermark energy is distributed non-uniformly across different frequency bands and time intervals based on the local characteristics of the host audio signal. The system identifies frequency regions and time periods where the audio signal provides natural masking, and concentrates watermark energy in those regions. This local optimization allows detectable watermark levels without creating audible artifacts in critical frequency ranges
Solution Approach 2:
The system exploits the natural masking properties of the host audio signal by embedding watermark energy in frequency and temporal regions where the audio content naturally masks the watermark. What would normally be harmful (watermark energy that could be audible) is converted into a benefit by strategically placing it where the audio signal itself provides camouflage, thereby achieving detectable watermarks without audible distortion
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective tracking of media consumption and control of devices through imperceptible audio watermarks, enhancing data collection and device responsiveness in media monitoring and control systems.
Implementation Method 1
a code may be inserted into the audio or video of media, wherein the code is later detected at monitoring sites
Implementation Method 2
utilizing methods like discrete Fourier transformation and error correction to ensure robust extraction
Data Source
AI summary
Methods and apparatus to perform audio watermarking and watermark detection and extraction are disclosed. Example apparatus disclosed herein are to select frequency components to be used to represent a code, different sets of frequency components to represent respectively different information, respective ones of the frequency components in the sets of frequency components located in respective code bands, there being multiple code bands and spacing between adjacent code bands being equal to or less than the spacing between adjacent frequency components in the code bands. Disclosed example apparatus are also to synthesize the frequency components to be used to represent the code, combine the synthesized frequency components with an audio block of an audio signal, and output the audio signal and a video signal associated with the audio signal.