Audio Watermark Encoding Using Self-Correlation for Reverberation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing audio watermarking technologies face challenges in detecting watermarks in audio data due to reverberation effects, leading to inaccurate detection and inefficient processing, especially when watermarked audio is output by loudspeakers and recaptured by microphones.

Innovation Solution

The system employs a self-correlation algorithm and bi-layer watermark encoding structure using eigenvectors and sign sequences to cancel repetitive portions of the original audio segment, enabling accurate detection of audio watermarks despite reverberation, and allows for embedding multiple watermarks in audio data for parallel decoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If audio watermarking is performed on audio data that will be output by loudspeakers and recaptured by microphones, then the system can enable unique functionality between devices, but reverberation effects cause inaccurate detection of watermarks

Engineering Contradiction:
Improveunique functionality between devicesVSAvoidwatermark detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by embedding watermarks in advance and using self-correlation algorithms to anticipate and compensate for reverberation effects before they interfere with detection accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback mechanisms where the self-correlation algorithm processes the watermarked audio signal to generate corrections that compensate for reverberation, continuously adjusting the detection process to maintain accuracy despite acoustic distortions

Inventive Principle:
Principle #23Feedback

2Ease of manufacture

If existing audio watermarking technologies are used, then the process is simple, but detection becomes inefficient and inaccurate due to reverberation

Engineering Contradiction:
Improvewatermark embedding simplicityVSAvoidwatermark detection efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The self-correlation algorithm performs self-service by processing the watermarked audio signal itself to extract and correct reverberation effects, eliminating the need for complex external processing systems while improving detection efficiency

Inventive Principle:
Principle #25Self-service

3Productivity

If multiple watermarks are embedded in audio data for parallel decoding, then processing complexity is reduced, but the encoding structure becomes more complex

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidencoding structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system segments the watermark embedding process into parallel components, allowing multiple watermarks to be encoded and processed simultaneously, which reduces overall processing complexity while maintaining manageable encoding structure through modular design

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS20210327442A1Audio watermark encoding/decoding
Publication Date: 2021.10.21 AMAZON TECH INC
  • US20210327442A1 patent drawing
  • US20210327442A1 patent drawing
  • US20210327442A1 patent drawing

AI summary

A system may embed audio watermarks in audio data using an Eigenvector matrix. The system may detect audio watermarks in audio data despite the effects of reverberation. For example, the system may embed multiple repetitions of an audio watermark before generating output audio using loudspeaker(s). To detect the audio watermark in audio data generated by a microphone, the system may perform a self-correlation that indicates where the audio watermark is repeated. In some examples, the system may encode the audio watermark using multiple repetitions of a multi-segment Eigenvector. Additionally or alternatively, the system may encode the audio watermark using a binary sequence of positive and negative values, which may be used as a shared key for encoding/decoding the audio watermark. The audio watermark can be embedded in output audio data to enable wakeword suppression (e.g., avoid cross-talk between devices) and/or local signal transmission between devices in proximity to each other.