Echo Cancellation via Nonlinear Amplitude Detection

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Solution Overview

Problem

Existing echo cancellation systems struggle with nonlinear amplitude processing, such as dynamic range compression, which can lead to echo leaks and residuals, especially in systems without a loopback signal for reference.

Innovation Solution

A computer system with an audio processing module, an echo cancellation module, and a control module that detects nonlinear amplitude processing by analyzing amplitude distributions using histograms, allowing for adaptive echo cancellation tuning to prevent echo leaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If echo cancellation is applied in systems with nonlinear amplitude processing, then echo leakage is reduced, but detection complexity increases

Engineering Contradiction:
Improveecho cancellation performanceVSAvoiddetection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by detecting nonlinear amplitude processing characteristics in advance before echo cancellation is performed. The control module analyzes the processed first audio signal to identify characteristics of nonlinear processing, then uses this detection to adaptively adjust echo cancellation parameters. This preliminary detection enables the system to prepare appropriate cancellation strategies beforehand, improving overall echo cancellation reliability without requiring complex real-time adjustments.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If adaptive echo cancellation tuning is implemented, then echo leakage is eliminated, but processing time increases

Engineering Contradiction:
Improveecho cancellation performanceVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements partial action by selectively applying adaptive echo cancellation tuning only when nonlinear amplitude processing characteristics are detected. The control module compares amplitude distributions and determines whether adaptive tuning is necessary based on the presence of nonlinear processing characteristics. This selective approach avoids the continuous processing overhead of always-applying adaptive tuning, thereby reducing processing time while maintaining effective echo cancellation performance when needed.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If amplitude distribution analysis is performed, then nonlinear processing detection accuracy is improved, but computational load increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidcomputational load
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by focusing amplitude distribution analysis on specific critical regions rather than analyzing the entire amplitude range uniformly. The control module compares amplitude distributions of processed and original audio signals, identifying local deviations that indicate nonlinear processing. This targeted analysis approach improves detection accuracy by concentrating computational resources on the most informative regions of the amplitude distribution, while reducing overall computational load compared to exhaustive analysis of all amplitude values.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3058710B1Detecting nonlinear amplitude processing
Publication Date: 2022.03.30 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3058710B1 patent drawingFigure 1
  • EP3058710B1 patent drawingFigure 2
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AI summary

Disclosed is a computer system comprising an audio processing module, an echo cancellation module and a control module. The audio processing module is configured to process an audio signal and output the processed audio signal to e.g. a speaker (or similar) of the system. The echo cancellation module is configured to cancel echo from an audio signal received via e.g. a microphone (or similar) of the system. The control module is configured to detect a condition indicative of nonlinear amplitude processing by the audio processing module and control said echo cancellation by the echo cancellation module based on the detected condition.